Sexy!
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Sexy!
Has there been any talk about possibly using a Jerico trans?
Nope. Jerico race transmissions use straight cut gears with no synchros. We are building this kit around more of a dual-purpose street/track car, with a synchromesh transmission.Quote:
Originally Posted by vejatabul
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But our LS1 kits are often used with major changes like this. Our E36 LS1 customer above used a Jerico in his BMW with our kit - just made his own driveshaft. It was a competition only hillclimb car.
With enough effort anything is possible. :D
Sweet, when do I get to drive it?
I have been on the lookout for a good used Jerico for one of my project cars for a while. I am certainly interested in the straight cut gears, and after driving a Jerico equipped car a few years ago, I was hooked.
Project Update for January 4, 2014: Wow, over a year without an update? Yikes. While it looks like I have been avoiding this build thread, we have been plenty busy working on this project and many others over the past 14 months. Most of the work we have been doing on this project over the early part of 2013 had to do with upgrades to the shop and building fixtures we needed to delve further down the rabbit hole on the Miata LSx swap. Later in 2013 we also tried a number of oil pans, designed and built a new tubular front crossmember, did all of the geometry calculations then mounted the new front suspension bits, and then we finalized the wheel and tire package. We also worked on a lot of other customer cars in that period, built a few race cars, developed our BMW E36 LS1 swap kit extensively, released our BMW E46 LS1 kit, and a number of suspension development projects in the same time period.
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All pictures in my posts can be clicked for higher rez versions
We also had a very busy racing schedule in 2013, running 15 events with NASA (among many other groups' track and autocross events) in our TT3 prepped Mustang, shown below. We won 13 of those, got one 2nd and one 3rd, setting 8 track records along the way, while testing all sorts of aero and suspension work (we race to test, and test to race). Another project that kept us busy was developing a new set of NA/NB Miata shocks shown below. These are custom built with Bilstein Motorsports components, using massive 46mm monotube pistons, machined and assembled at Vorshlag, then custom valved by Maxcyspeed & Co. We just finished our final round of track testing last weekend, testing the latest valving package for a dual purpose street/track set-up. I had a blast hooning around in the tester's 2001 Miata below at Eagles Canyon Raceway. These dampers should be in production in Q1-2014 and we will have more information about these in the New Damper Offerings forum thread.
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One thing to note about this post: starting in early 2013, I started making ALL of the pictures in all of my forum posts click-able for larger sizes. With a photographer like Brandon on staff it is a shame to only show the little "small" versions in our posts. So if you see an image you like, click it for a higher resolution version of the same image.
Before I get going on this update I wanted to shout out to V8Miatas.net - Just found this forum recently, which looks to be a great resource for all sorts of V8 Miata swaps, as the name suggests. Our Alpha LS1 build thread was added there today at this location. I have already learned a few things reading other threads there, so if you have plans for any sort of V8 swap in any generation of the MX5 chassis, you should head over there and sign up.
Shop Upgrades Lead To LSx Swap Progress
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So one of the things we needed to work on this Miata LS1 car was a 4 post lift, which we finally ordered and installed in early 2013. This made it easier to do drivetrain mockups. We quickly realized that we also needed a chassis dolly to make the Miata easier to move around once the subframes were out. So we built that in summer 2013, and soon modified it to fit two other chassis. Now that dolly thing gets used on a daily basis (should have built one of these sooner) to move a car around the shop that has no suspension, crossmembers, or wheels.
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Believe it or not, the lack of the 4 post lift and chassis dolly were big impediments to this Miata LSx project. Since we are still in a somewhat small shop space we couldn't afford to have the Miata stuck on one of our lifts for more than a day or two, which kept us from pulling the front subframe out for more drivetrain mockup (ever try to move a car around without even subframes in it?).
The Real Engine Swap Work Begins
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Once the lift and chassis dolly were built we rounded up the hardware needed to get the TKO-600 transmission mounted to another LS1 block we have, then put that mockup drivetrain in the car for some testing with the REAL transmission. Before we had eyeballed the TKO in the tunnel but not while attached to the block. This helped us see what the next piece was in the way...
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After we did that round of LS1+TKO mockups we quickly realized that the OEM front crossmember was a HUGE hindrance to this swap, as even heavily modified and hacked up it would be in the way of the engine, oil pan and exhaust headers. We refuse to accept the huge compromises that come with "block header" exhaust headers on any of our swaps, so a new tubular front crossmember was going to be required.
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You can see above some of the structure of the frame fixture that bolts to the body dolly, which Ryan built for the NB Miata. There's actually a lot of steel rectangular tubing you cannot see in this pic. The rolling cart attaches to this frame fixture from underneath the lift. This fixture was built to allow the car to sit at the desired ride height w/o suspension while sitting directly on the lift, with the rectangular tubing setting the chassis height. He then mocked up some 265/35/18 tires at both ends for a quick look. If you shove them in hard enough they almost fit under the fenders, heh.
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Choosing Tires and Suspension To Build Around
We knew early on that we wanted to upgrade all of the factory (and very weak) 4 x 100mm NA/NB hubs hubs to 5 x 114.3mm RX8/NC hubs. The 4 x 100 hubs are a common failure point up front on Miatas that see any track time, and keeping the rear 4 x 100 hubs would limit the halfshaft strength greatly. Going to 5 x 114.3 bolt pattern opened up a lot more wheel and brake choices as well. Doing this "hub upgrade" is more work than you might think - this meant new uprights and control arms, so the NB suspension pick-up points on the crossmember were no longer sacred... so we might as well ditch it, right? Well we tried to keep the stock crossmember, probably far too long into the swap development. We tried cutting it to make room for this or that (like some of the kits are fond of doing), modifying the pick-up points, but it was getting weaker and more customized.
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Meanwhile we had been mocking up this RX8 front control arms and uprights and even tried an 18x10" wheel and later a wheel and tire. Ryan put in several days of work, and with Jason's help, they did a lot of measurements and calculations and got the front suspension sorted out fairly well. At this point we knew we would be able to re-use the RX8 front spindles, brakes, and control arms. I was worried we would need to fabricate control arms, but it all fit very well with the forged aluminum RX8 arms. Small victory.
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Video we made for the customer, showing the RX8 suspension and 18x10" wheel in action
In the video linked above we were showing the customer the current location of the wheel and suspension with the big 18x10" wheel, to which we later mounted a 285/30/18 tire. This video shows the front 18x10" wheel turning at ride height, and we later made some adjustments to clear that wheel at full lock, inboard (obviously the fenders will need to be cut and flares added to cover the tire). Our customer has had regular e-mail updates every 2-4 weeks, showing all of what you see here and more. We send these email updates with pictures and videos to all of our long term project customers - basically anyone that has their car in our shop for anything more than just "day work".
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Later a set of 18x8" Mustang wheels (from my 2013 Mustang GT) were installed, shown above left. We noted that these barely fit under the stock fenders, but they didn't have enough positive offset. We might pick up some higher offset RX8 18x8" wheels (above right) and tires, which would sit farther inboard. This could possibly avoid the need for cutting and flares for some folks. Luckily, our Alpha customer is going with the 285mm tire option. Why so much tire? Well the LS1-based 5.7L motor that was built for this car will make 425-450 whp, and in a 2600 pound car with a short wheelbase, that is downright hair raising... we felt that a 285mm tire (Hoosier!) was going to be barely enough to keep it on track when the loud pedal is cranked up to 11.
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One thing that had me a little worried during our wheel and tire mock-up was tire height. Most NA/NB Miatas are using a 23" tall tire, which is SUPER SHORT and only come in sizes out to about 215mm or the occasional 225mm. We went away from the typical 14-15" wheels to clear larger RX8 front "sport" rotors, which at over 324mm diameter are too big to fit inside a 15" or 16" wheel. Then tire width choices started to come into the picture... there just wasn't anything wide enough in 14, 15, 16" or even 17" diameters (the last two diameters tend to top out at a 255mm tire width for most brands), so we jumped straight to 18" - which currently has the most options for wider tires in both street and race compounds, covering widths including 275, 285, 295, 315 and beyond.
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We're building our TT3 Mustang around a 345/45/18 in the 2014 season, for instance. You can almost never have too much tire width on a race car...
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Turns out there wasn't any tire anywhere near 23" tall once you left the skinny options in the 14-15" wheels, so we chose the shortest tire that is also wide that we knew of - the 285/30/18. This tire is normally the magic solution to "going wide" on track or autocross cars, and we've used this 24.9" tall monster tire on lots of BMWs (see above right, which has a bit more tire height room), EVOs, Subarus, and more. They even are used on RX8s and NC MX5s, but those cars have a lot more "wheelhouse" room than the NA/NB chassis. So we will likely cut the front upper frame horns for more clearance at full bump travel (then add back more structure with welded steel tubing). The above left picture shows the suspension at about 1.5" of bump, which isn't enough. Oh well, using a 2" taller than stock tire causes some problems we will have to overcome, but they aren't anything we haven't tackled before on other chassis.
New Crossmember Development
Once the tire was chosen and the front hubs and suspension components were tested and mocked up, we were ready to start burning in the pick-up points onto some sort of crossmember - either the stock piece or a custom design. At this point it was obvious that the OEM front crossmember was the next big stumbling block and it had to come out, once and for all. We just couldn't save it (it was already cut-up so much to clear the engine that it would need major reconstructive surgery), we didn't need it (we were changing all of the suspension pick-up points), and it was just in the way. So first the Vorshlag crew fabricated a crossbar that held the front of the engine from the top, which rested on a part of the upper chassis that wasn't going anywhere. Then they made a similar and also temporary rear transmission crossmember that was bolted in place, so the driveline position and angles were set. In the step above you can see the OEM crossmember out of the car for a bit, but now it was time to be fully replaced.
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Now that the drivetrain was where it needed to be we connected the dots to build our new front crossmember. Using lengths of 1.75" diameter x .120" wall DOM steel tubing, Ryan measured then mandrel bent the new fore-aft frame members. These tubes were spaced inboard enough to maximize exhaust header space as well as set the final lateral and vertical locations for the RX8 lower control arms, which had geometry already determined above. These main fore-aft tubes bolt at both ends of the engine bay, onto factory chassis mounting locations that have substantial strength. Unlike the stock front crossmember, which mounts at the rear of the engine bay and at the midpoint (where the suspension parts mount), the new tubular design would mount at those points plus forward at the front tow hook tie down mounting plates. Our crossmember should make for a more rigid chassis when it is completed, with less cowl shake and more stable suspension mounting.
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You can see Ryan welding the front mounting position of the crossmember tubing at the tow hook mounting plate, which is a beefy piece of plate steel bolted to the front of the chassis with plenty of bolts on both sides. With these two main crossmember pieces in place several things were then test fit. First, 3 different LSx oil pan designs were fitted to see which provided the best clearance to the lateral tubing member that was still needed as well as clearance to the NB Miata steering rack.
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Each oil pan design had some advantages and disadvantages, with the total depth of the pan's sump driving how low we could get the drivetrain in the chassis, and the front section of the pan limiting where the steering rack would end up. In the end we chose the oil pan from the 1998-2002 Camaro, which is commonly available from the aftermarket. The Holley swap pan and the GM Muscle Car swap pan both had issues that could not be overcome. Luckily we didn't have to settle on a fabricated oil pan (these always seem to leak), the GTO double-hump pan (we have used that one and do not like it) or another cut-up OEM pan. There are good baffle/trap door kits made for the Camaro pan (Improved Racing's unit is preferred) and we have a lot of miles on track with this oil pan and baffle in BMW E36 LS1 swaps.
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This is our prototype front NA/NB engine swap crossmember - additional gusset plates and tubing will be added before final welding
The final LSx oil pan we picked ('98-02 Camaro) is shown above, after the lateral tubing member was tack welded in place. Two vertical tubing members were also added, welded mid-way from front-to-rear and landing on some plate steel that bolts to the stock crossmember front mounting holes (which doubles as the upper control arm inboard mounting point). This makes for a completely bolt-in tubular crossmember, with extra mounting bolts/locations, once we get it into production (we will replace the OEM tow hook tie-down plates with a new, Laser Cut plate version). It also has a LOT more room for the engine and exhaust headers, so we can develop real exhaust headers - which can make upwards of a 50 horsepower difference on an LS1 V8 over the block-hugger super shorty headers some kits are stuck with. And this crossmember could work with a LOT of other engines as well.
We weren't going for the "lightest crossmember on the market" here, as I cannot count how many lightweight tubular crossmembers I have seen bend or fail. No, we wanted the STRONGEST possible fabrication we could come up with. The .120" wall thickness on the 1-3/4" DOM tubing we used might be overkill, and we could step that down to .095" wall on a later prototype piece (we will surely make some tweaks to this design before it is ready for mass production), but when it is completed we will weigh this first tubular unit vs the stock OEM stamped sheet steel fabrication and see where everything shakes out. A crossmember is not somewhere you want to skimp on.
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Throttle Body Clearance, Air Cleaner Routing, Possible Hood Ducting?
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Of course before the oil pan and engine heights were finalized we tested with an intake manifold and throttle body on the mock-up LS1 engine, then tested with the stock hood in place. We had plenty of room up top, but realized that due to the short length of the Miata engine bay the intake inlet tube would have to go "over the top" of the radiator support (yes, this means we have to lose the factory hood latch).
We've done this type of air inlet re-routing before, like on our TT3 Mustang shown below.
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This was one of the many custom tweaks we had to do on that car to make room for a deeply ducted hood, which vented the back of the radiator and made the front splitter much more effective. This had an accidental side effect of offering a lot more cooling capacity (and front downforce) to that car, so we might do something similar on this LS1 Miata, and of course use a bigger radiator at the same time.
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Ducting the Mustang's hood made the front splitter we built MUCH more effective, both for cooling and front downforce
There are plenty of Corvette style air filter housings we can choose from, which was the air filter we ended up with on our TT3 Mustang. So after the intake manifold was fitted the Miata's engine height was locked down, and the driveline down angles were set at the transmission. Next up it was time to burn in the RX8 suspension mounting points to the new crossmember...
Final Welding of Suspension, Brakes Added
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Our fabricators Ryan and Olof made some steel mounting plate sections on the bench that were then fitted to the tubing and tack welded in place on the crossmember. Then the suspension was mounted up, the wheels were added, and everything was set to ride height... to re-check camber, caster, toe, and then camber and caster change with suspension travel. Obviously you don't want caster change with suspension travel, so that was dialed out.
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It doesn't look like much but dozens of hours were burned getting these mounting points welded in, measured, moved, and tweaked. Mazda-sourced eccentric bolts are used at the same suspension mounting locations as the RX8, to be able to adjust camber and caster. And while some of you suspension savvy readers might point out that the upper arm's mounts aren't perfect (we wish they were about an inch higher), they are as perfect as we could make without cutting the frame out of the NB chassis or going to custom control arms.
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There's a lot to be said for re-using OEM forged aluminum arms, which can make for easier service and maintenance down the road. We checked the dynamic camber change and it turned out to be pretty reasonable, too. Remember: Vorshlag specializes in suspension development, so this was an area we really made sure to get right. And we could see something in track testing that might make for future changes before this kit goes into production, too.
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Seeing the old front suspension and brakes on the shop floor next to the new stuff is quite a difference. We're upgrading from a 254 x 20mm vented front Miata front rotor to a 323 x 24mm RX8 Sport front rotor. Going with RX8 hubs gives us a lot of Big Brake upgrade kits to choose from down the road, if needed. This customer wants a car he can track, autocross and street drive across country - and it will have 450+ hp and sport 285mm tires, so it will have some extraordinary braking requirements for an NB Miata.
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These RX8 calipers and rotors are all Centric premium units that we sourced new, so it should make for a good starting point for track and street testing. We will also add front brake ducting, at a minimum, before it sees any track testing. That makes a huge difference on most road course cars we deal with, and it doesn't cost a lot nor does it have any downsides for street driving.
What's Next?
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With the front crossmember, brakes and suspension nailed down and in prototype form it is time to move to the rear suspension. The front bits had so many variables that all cross over each other, but without steering involved we're hoping the rear will go more smoothly and quickly. As you can imagine the customer is getting anxious to drive his car, and wants to run events this year, so we've got to get crackin!
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None of the OEM rear control arms, brakes, and hubs will be re-used. Again, we felt that the small-ish rear hub's inner spine size would limit the power capability of any halfshaft that could be built for these cars. I've seen fellow racers shred axle after axle in LS1 equipped Miatas, and I don't want to get stuck with those limitations on our swap. So this means it all has to come out and we get to start over. Yay.
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The diff housing we are using is of course the 31 spline Ford 8.8" aluminum IRS casing that was used on the 1999-2004 Mustang Cobra. This was also the same housing used in Lincoln MarK VIIIs, and steel versions were used in the Thunderbird and Explorer chassis. The new S550 Mustang chassis looks to have the aluminum version as well (we should have one of these Mustang's soon for chassis/suspension development in late 2014 and a full season of racing in 2015). All this means is these diff housings are both common and affordable, not to mention strong as an ox. Aftermarket choices abound for gearing and internal differential options, too. We also have the rear uprights chosen, which are a commonly used unit for Cobra kit cars.
For now we will use the OEM rear subframe to mount things to, at least during mock-up. Once these uprights and the diff housing are mounted and set at the right heights and locations, we will fabricate upper and lower control arms, check the suspension geometries, then move to the halfshafts. This will entail a lot of fiddly work, measuring and calculations, of course, but compared to the front bits (which had to have an engine, transmission, suspension and crossmember all mate up) it should be a little less work.
Until next time, thanks for reading.
Project Update for June 25th, 2014: Long time no post on this project once again, but with some recent changes and progress we have regained some lost momentum and we are pushing to get this prototype LS1 NB Miata on the road by this Fall. After a spurt of work in January and a little more in April, some real time was spent on this project in May. Let's get caught up.
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The biggest progress of late was a new milestone that was started and finished since the last post - the rear subframe and suspension was constructed. Right now the car still sits on 18x10" wheels and 285/30/18 tires at all 4 corners, with the new RX8 front suspension tacked up as well (see above). The front obviously needs more negative camber (and more adjustment range), which we're working on next.
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Ryan, that started fabrication on this project has left us (left) but our new fabricator, also named Ryan, is on the case (right)
We had a few delays on this project in the months since the last post, due to a few unforeseen changes here at Vorshlag. For one, our lead fabricator Ryan B (above left) left us after almost 3 years of great work to pursue his college degree full time. He was working here part time for the past year and whenever we had to steal him for major fab work at our shop he didn't get to focus on the Miata swap often or for long. After he left we searched for over a month and found another great fabricator to join us, Ryan H (above right), who joins us with lots of race preparation and fabrication experience from a Daytona Prototype team and other previous race shops.
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As soon as Ryan H started here we buried him in fabrication work on a customer's V8 swapped race car, then he spent 100 hours working on the Pikes Peak Subaru above. Once those pressing deadlines were passed he got to spend about a week and a half working on the LS1 Miata and a lot of progress happened, back in late May.
Custom Rear Subframe Construction
We weren't sure which way the rear subframe and suspension would go until we just dove in and started mocking up parts. We knew the factory rear hubs were going away, as we wanted to fix the problems we've seen in our V8 swaps to this chassis when we made ours - namely, busted halfshafts out back and fragile hub bearings at both ends.
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There wasn't much to start with when Ryan got to the back of this 1999 Miata. We had looked at using part of the old factory rear subframe structure and cutting it up to fit the Ford 8.8" aluminum center section. The problem was the new diff was so large that most of the top of the old subframe had to be removed and very little structure would be left.
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The stock differential housing, rear subframe and rear control arms were removed so we could mock-up the new parts we wanted to add. The rear hubs/uprights were ordered then we mocked up the Ford 8.8" IRS diff housing...
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There was no way that 75 pound aluminum diff housing could fit without hacking the stock rear subframe beyond recognition, so it was set aside intact and fabrication of an all new rear subframe was started. The Ford diff housing was mocked up using some straight tubing passing through the new rear hubs and uprights we chose for this new set-up. These were chosen for their "high torque capacity" sizes on the hub bearings and the splined size for the halfshafts. Nothing that uses the OEM rear NA/NB Miata hubs or input spline can live much beyond about 250 ft-lbs of torque for very long, at least not with grippy R-compound rubber. The LSx motor that has been built for this Alpha car will make more than double that (450 ft-lbs+)
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The uprights (below) we used are aluminum, very strong and work with the 5 x 114.3 mm bolt circle hubs shown above. This rear hub will work with the same wheel bolt pattern we're using up front, which we borrowed from the best OEM Mazda front bits. The entire front suspension is based on the beefier RX8 hubs, uprights, brakes and forged aluminum upper and lower control arms.
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We also switched to a different rear cover for the Ford 8.8" IRS housing, which is shown above, deciding not to use the 2004 Mustang Cobra cover. This dual ear "winged" mounting style cover used is similar to the style that comes on the BMW E36 chassis and somewhat like the C4 Corvette Dana 36/44 housing - both cars we have worked with and raced hard for many years without issue. This style cover is easier to work on and mount to than the "clamped center mount" '99-04 Mustang Cobra rear cover used in our earlier mock-ups. This newer cover also has both fill and drain plugs on the cover, for use with a possible differential fluid cooler (common for heavy road course use).
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The goal was to be able to use stronger OEM based and commonly available hubs, brake parts & other consumables (not one-off fabricated or race-only parts), and have the same wheel bolt circle front and back. This way if you blow through your brakes or wear out hubs at a track event, you can run to a local parts store to get replacements fast.
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Ryan jumped into the new rear suspension and subframe design with both feet and spent a full day making measurements (see above) and checking suspension geometry using 3D node software, to check camber change through suspension movement. Using the short upper and long lower arms and moving the pick-up points in computer space, then checking the camber change under movement. The final pick-up points and geometry chosen looked great and the dynamic camber change was well within normal parameters.
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This is major fabrication work coupled with suspension design, and not something usually done by just "anyone that can weld". Luckily it wasn't too challenging for our crew - we are primarily a suspension shop and all of us are racers - and the new subframe and suspension design was knocked in a little over 70 logged hours.
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The start of the upper structure of the rear subframe is shown above and left. The beefy new subframe unit will bolt to the 6 factory mounting studs in the rear of the chassis, without any cutting or welding. Once it is finish welded I will share the final weights vs the OEM bits, but it should add little to no weight over the stock rear assembly. The picture above right shows some of the tubular steel custom rear lower control arms going together. These are adjustable and feature polyurethane mounting bushings for some cushion but nowhere near the slop of a rubber mount. This should be suitable for a dual-purpose street/track car, but we could also make these arms with spherical ends for track-only set-ups.
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These hub-mounted stands worked well during geometry checks and suspension mock-up and fabrication. Lots of fixtures and welding jigs were built to be able to make the parts uniformly and mirror imaged from side to side.
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Here you can see the aluminum 8.8" diff housing starting to be fitted to the tubular steel rear subframe structure. Polyurethane (red) bushings were used in the front and rear mounting locations for this housing.
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The front diff mounting brackets are shown below at right. There is a gusset to add on each side but otherwise that section of the subframe is finished.
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You can see the rear chassis studs and bolt holes that the new subframe mounts to, below. There are some scalloped areas that will be added for more bolt/nut clearance, and small tubular gussets here and there, but this is the final layout we're going with.
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There are a few gussets to be added, then final welding can be done and the subframe removed for powder coating.
What's Next?
We've already had started on the front subframe and it was mostly done. Now we are tweaking the front geometry to allow for more camber and caster adjustment, using the RX8 eccentric bolts/washers and OEM style "cages" around these bits. Once the front subframe is completed we will design and build the LSx V8 motor mounts (takes about a day and a half). After that the prototype header fabrication and a driveshaft can be built. We have an aggressive schedule to finish this car this year, so stay tuned for more updates. We will be making production runs of both subframes, for use with LSx V8 swaps as well as racers with boosted Mazda engines that want the reliability and durability of the higher strength hubs, halfshafts and diff housing we're using.
Thanks,
Impressive!!
Curious though, for the people who may buy your rear end kit for the strength, will you be integrating some sort of PPF mounting solution? Or developing a transmission mount for the factory transmission?
Project Update for December 17th, 2014: We've been busy on the Miata over the past few months but I've just been too busy to get caught up on the forum updates. We just finished construction and a big shop move for Vorshlag, doubling our available space, which ate up a lot of my time. This move has made for some extra room to work on projects like this, to add some new fabrication equipment, and just this past week for two CNC machines (lathe and mill) to finally make our machined Vorshlag products 100% in-house.
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Right after the move in November a majority of Vorshlag folks also went to SEMA and then we were competing in OUSCI (Optima Street Car shootout) in our TT3 Mustang. Then Jason went to the 2014 PRI show and took 100 pics of cool new parts. Ryan stuck around at our new shop in Plano, Texas, and worked on the Alpha Miata V8 and made some really good progress. Then he found some more days in late November and early December as well. Anyway, we have all been slammed, but big progress has been made on the Alpha Miata.
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The 2014 SEMA show and the OUSCI competition were fun but ate up a lot of time I where could have been updating various build threads
Front Suspension Follies!
Last time we updated this build thread, Ryan had finished re-checking the geometry on the rear bits, tweaking the rear subframe and making new rear control arms. That was back in June. In August he was freed up a bit and finish-welded the custom rear rear control arms. They are ready for shock mounts, cross bracing and custom half shafts at that point, but the rear subframe still needed to be final welded. He wanted to tackle the front before "locking down the design" (track width, ride height, etc) out back.
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Now we move ahead to some time he had in August, when he moved to the front, to re-run the 3D geometry on the RX8 spindles/arms that we already had mocked up and tacked in place to the custom tubular front subframe. Well... while it looked fine to the naked eye, once the wheel was at the proper ride height (now visible with the RX8 hubs mounted to the new hub-stands, shown above) the geometry was less than ideal. Once the pivot points were input into suspension analysis software it was obvious that anti-dive and bump steer were terrible. Still, I wasn't giving up on keeping the suspension/brakes "all Mazda" up front, so I had him stick with the RX8 bits a little longer and try to move the pick-up points to try to dial some of this out.
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Ryan cut off the previous pick-up points and made new ones, then rolled the mounting points as far as he could within the constraints of the stock front Miata tub and the RX8 arms. After sourcing some factory Mazda RX8 eccentric bolts and making the new control arm mounts that mimicked the factory subframe mounting points, it looked great and had the adjustments we needed, but the geometry still wasn't getting much better. He did some 3D measurements, saw some room to improve, then yanked the subframe and started over - making an all new front subframe section, from scratch, to gain some room for our the RX8 suspension at the lowered ride height and to fit with the big tires we had in mind. Two steps forward, one step back - that's how it works sometimes. The second, new subframe was tack welded together and had several improvements, and we would end up sticking with that through the next suspension iteration.
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After he re-installed the RX8 bits it still wasn't good enough, so our engineer Jason and I asked Ryan to just fabricate new control arms to use with the RX8 uprights and hubs, but after an exhausting search the OEM style ball joints for the RX8 (very funky taper and size - nothing like anything supported by the aftermarket) were not available separately, so this was a dead end. Bah! I finally pulled the plug on the RX8 spindles and pretty aluminum control arms. We had already acquired brand new RX8 brake parts, too. Oh well, some ideas just don't pan out. Lots of fabrication hours were wasted based on my notion of using OEM RX8 spindles, brakes and front control arms.
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After this latest wild goose chase we had Ryan stop working on the car for a few weeks while engineer Jason and I regrouped, to look for other front suspension and spindle solutions we could utilize. After this debacle we realized that swapping in another set of control arms wasn't going to work inside the narrow confines of the Miata without several miracles, so instead we focused our search on a good OEM uprights that was made for a double-A Arm suspension. The result was we found something much better than the RX8 bits - lighter, forged aluminum, even more common to find, with tons of aftermarket support, beefy front hubs, and dozens of OEM and aftermarket big brake options. So, what did we use?
When In Doubt, Just Use More Corvette Parts
Corvette C5 spindles were the chosen upright this time (C6 are virtually interchangeable, too) and the first one we purchased looked great - and proved to be significantly lighter, too. And honestly we don't care where the parts come from, if it meets the criteria for use on a hybrid build like this: use the best parts available, that can be purchased at the best price, with good aftermarket support, easily procured consumables, and the best materials/strength/design.
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The C5 aluminum upright was 5.6 pounds (13.96 pounds, with hub and ball joint installed - and the unit bearing hub is BEEFY!) compared to the 15.5 pound RX8 steel upright and hub. The nice thing is that the front and rear spindles on a C5 (and C6) are interchangeable (RF and LF are the same, LF and RR as well), which doubles your chances of picking them up second hand. Once we had one of these forged C5 spindles on hand, new ball joints were ordered next (we first made sure first that they were available separately!) and Ryan started making a whole new set of upper and lower control arms.
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These would be tubular, the right lengths, and after some analysis, end up with better geometry, and have more range of alignment adjustment than the "eccentric" bolts of the RX8 arms. We could now adjust camber and caster through a larger range and achieve proper geometry at the ride height we wanted without cutting up the Miata tub. The lower arms would house the C5 ball joints and the upper arms would accept the matching C5 upper. The ends we chose were firm polyurethane bushings and the lengths were to be adjustable. A lot of pieces were ordered, many more were custom machined, and a lot of hours were spent calculating, fabricating and measuring.
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Making this car as a one-off build would have been SO much easier - we would have just notched out part of the frame and made the RX8's control arms pick-up points fit in space where they would work for the geometry. But we have been going to great lengths to keep this subframe and suspension a reproducible kit, and to keep it a purely bolt-on set of parts, which meant not chopping a chunk out of the front frame section to move the upper control arms upwards. In the end we found that the C5 spindles, with the OEM ball joints aimed as they are, allows for the geometry we needed within these MX5 chassis constraints, using these custom control arms. BOOM!
Steering Rack Placement + New Steering Shaft
Once the new front control arms were fabricated and tacked welded, then geometries rechecked (both manually/visually and in software), it was at a good stopping point. Ryan then began to tackle the front steering rack mounting.
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The NB Miata steering rack was placed in the ideal location for the slightly altered wheelbase and new front Corvette spindles, keeping in mind the necessary oil pan clearance. We have a half dozen different LSx oil pans around here to test with, so we worked with those to find the right combination to clear the steering rack without adding bumpsteer. The final rack mounts were fabricated and tacked to the crossmember.
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This new rack location (and the small wheelbase change) would mean we would need new, slightly longer intermediate steering shaft assembly in the engine bay. Luckily we're used to making those for all of our BMW LSx swaps, so this is another bolt-on solution. What you see above is a mock-up - with one of the two aftermarket steering U-joints installed with a piece of 3/4" Double D shaft, to check lengths. The final solution will be a proper 2-piece collapsible steering shaft assembly like our many Vorshlag BMW steering shaft assemblies (see below). We make these to improve header clearance for V8 swaps on various BMWs, improve the heat resistance of the U-joints (the OEM steering shafts on LHD cars with inline engines are not meant to see exhaust heat) as well as to remove nasty rubber "rag joints" (steering shaft isolators) in the shaft, for better steering feel. We even sell a lot of these steering shafts to BMW racers who keep the BMW engine, just for the improved feel.
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Olof took a fresh NB steering rack core and converted it to a de-powered rack (we do this work on NA/NB Miatas often), welding up the bits necessary. We will use no power steering in this car initially, then switch to an electric assist solution if it is deemed necessary.
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Front Drive Accessories
Running no power steering pump will create some headaches but also solve some potential problems. Hydraulic fluid power steering assist is always a hassle in any car; the system can make for a huge mess when it leaks, and requires an engine-driven hydraulic pump, reservoir, cooler, and high end hoses on a tracked car. This system is the number one cause of on-track fluid leaks and underhood fires, so taking hydraulic power assist out of the equation is fast becoming part of our track-worthy upgrade list for all cars. Many OEM cars these days are coming with "EPAS" systems from the factory, which makes for aftermarket electric steering assist solutions that are numerous and proven - since many are just re-purposed OEM systems. This means they can even be cost effective. And lighter. And no longer based on flammable, high pressure fluid that robs power from the engine to pressurize. Win!
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A recent LS1 mock-up (October) with a set of accessories that does NOT have a power steering pump
And while it might seem simple to run any old LSx engine without a power steering pump, it was actually pretty tricky. This particular accessory drive arrangement was figured out on our FR-S LS1 Alpha swap, with some help from the itnernets plus some custom machined bits made here at Vorshlag. That car has an electric assist in the column, so it did not need the pump.
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We couldn't find a factory set of LS series engine accessories without the P/S pump, so we went with a proven version that had GOOD front clearance (shown above on the FR-S LS1) and narrow packaging, then the normal main serpentine belt routing was changed to bypass the missing power steering pulley. To accomplish this an extra idler pulley was added, and things were moved around to give proper belt wrap on each pulley - especially the balancer (SFI unit secured with a massive 12-point ARP bolt). We took some measurements then borrowed this set of accessories from the FR-S and test fit onto the built Miata LS1 motor, it fit great (see images above), so we're replicating that set-up now for the Miata. It took a few iterations but we finally got the right length belt (these were the "almosts")
Motor Mounts and Transmission Crossmember Design - With A New Twist
Once the newly modified, de-powered NB steering rack was mounted to the subframe with some beefy, fabricated brackets (see above) we wanted to then lock down the designs for the motor mounts and transmission crossmember. But now that the tubular subframe was built and the rack was tweaked to fit the C5 spindles, Ryan saw some extra room and tried something I didn't expect... he put a Tremec T56 6-speed behind the LSx mock-up motor and stuck it back in the car. Again. Yes, after all the testing and trouble we went through to make the Tremec TKO600 5-speed fit, he went and stuck a T56 in there.
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I had told Ryan when he came on board at Vorshlag that the T56 would never fit this car, both because we tried this transmission before (with the OEM crossmember, and then a cut up OEM crossmember) as well as the fact that all of the other LS1 swap kits for the Miata require cutting the tunnel to make the T56 fit this car. "Waste of time."
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Thankfully, I was wrong this time. Now the bigger, stronger T56 did fit - and fit with room to spare! Apparently in our previous T56 testing the Miata's OEM front crossmember was the limiting factor. That big, bulky plate steel structure moved the drivetrain up significantly, which is why the T56 never fits the Miata tunnel on most swaps without cutting the tunnel to make room.
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Left: The initial LS1/T56 mockups were a bust with the OEM crossmember in place. Right: With the tubular crossmember we have lots more room
This is because the LSx/T56 drivetrain is being moved upwards inches from where we have our drivetrain. With our latest (version 2.0) bolt-in tubular front crossmember, the engine sits lower and so does the transmission, so now it fits. It still has ample ground clearance to the oil pan, which is tucked up just above the bottom of the crossmember and bottom of the Miata tub. The T56 shifter location lines up perfectly with the factory Miata shifter hole. Moving this drivetrain down worked another miracle, and it lowers the CG, too. Win-win.
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That big transmission change threw me for a loop, but so be it! A brand new Tremec T56 Magnum costs more than the TKO600 new, but not by much, and its a more popular trans so we called up our Tremec supplier and we had a brand new close-ratio T56 Magnum on hand the next day.
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Tremec T56 Magnum - close ratio version - rated to 700 ft-lbs of torque!
If you know anyone that needs a GM-style TKO600, brand new, we will have it listed for sale here until it is gone, for less than they sell for now. We still have to get the correct flywheel, clutch and pressure plate for the T56, but those bits are already on order and should be here next week. During all of the transmission testing our crew removed the mock-up LS1 motor for the last time and installed the built 5.7L LS1 that the Alpha customer purchased for this build, made by the masters at HK Racing Engines.
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Left: The built LS1 with borrowed accessories and LS3 intake in the Miata: Right: LS1 with same accessories and balancer in FR-S
This motor has a built bottom end, CNC ported heads, big lumpy cam, proper valvetrain, and all sorts of race parts inside. Should make in the neighborhood of 450 whp on pump gas. Ryan chose the 98-02 Camaro oil pan during his testing, so we ordered an Improved Racing oil pan baffle kit to fit this pan and that's in place. We won't build a track-duty car with an LSx without an oil pan baffle from Improved Racing. After talking to those guys at SEMA they realized how many of these LSx baffle kits we've used over the years and made us a dealer, so we'll add these to our website shortly.
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Left: The accessory arrangement we used has ample room for an A/C compressor, as shown. Right: Improved Racing oil pan baffle will be used
Once the oil pan and accessories were locked down, then Ryan could start to build the motor mounts (see below left), which he knocked out in about a day. These look like many of the designs we have used on BMW E36, BMW E46, BMW E30 and the FR-S/BRZ swaps done here at Vorshlag.
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A production set of similar mounts for our BMW E46 LS1 swap, black gloss powder coated. We make these in-house with CNC laser cut pieces
When you have a robust, proven design that has been made 100s of times, you use it. These make for a strong, reliable, low vibration mount that has no movement when torque is applied. These then bolt to a gusseted, plate structure welded to the tubular subframe (see below right).
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To make the transmission crossmember required a bit of extra work, at least on this Alpha build. Like on the FR-S swap (after we made room for the longer T56 Magnum XL we used on that car) this NB Miata chassis has no transmission crossmember mounting on the chassis. The front mounting points of the "PPF" on the NA/NB Miata is the transmission mount (which is similar to Corvettes from C4-C7), but we ditched that since the T56 Magnum had no provisions for mounting this ladder frame to the back of the tail housing. Modifying the transmission to fit the factory PPF would be a nightmare to reproduce in kit form.
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Left: The heavy stock dash was removed to make room to pull the carpet. Center: Inner plate brackets. Right: Shifter lines up very closely
To make room for the next step, the dash was removed. Why? Two reasons. First, we wanted to see how much the entire NB dash structure weighed. 49 pounds is the answer. Second, to remove the OEM carpet intact the dash has to come out. We needed to add some backing plates inside the tunnel under the carpet, to hold the transmission crossmember brackets inside the tunnel, so the carpet was pulled. For the kit version we'll have templates for where to drill holes and you can slit the carpet to slide the plates under the carpet without removing all of this, hopefully. Mazda just makes it extra hard to remove the carpet on these cars - dash and everything is in the way.
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Left: Outer tunnel reinforcement plates. Right: The transmission crossmember bolts to inner tunnel reinforcement plate mounts
As we did on the FR-S swap, mounting plates were bolted to the chassis on both sides of the transmission tunnel. These can stay in place, and the crossmember then bolts to the inner mounting bracket plates. This sandwich of plates (one set inside the tunnel and the matching plates inside the cabin) makes for a strong mounting arrangement which we've used in the past. The removable crossmember bolts to those inboard mounting plates and this, in turn, is what the transmission bolts to.
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The raw steel crossmember shown above is semi-finished; we will add more gussets when we final weld the assembly. It has lower reliefs that could clear up to two 4" diameter exhaust tubes, but we will build this car with a dual 3" exhaust - which still has massive flow potential. We used our proven red polyurethane transmission mount bushing from other T56 swaps in this set-up, but we also make a machined Nylon busing for a pure race car.
Subframe Final Welding - Times Two
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After the drivetrain mounting was designed and built, the motor was once again removed and the tack welded front subframe came out for final welding. This step took two solid days, as welding fixtures had to be built and then additional gussets had to be made and welded in place as Ryan went through the tacked joints and TIG welded everything. The end result is shown below, and is a very strong work of art. Production fixtures would key all sorts of CNC laser cut pieces into place, and that is much more elaborate, but we will make those when we blow the car apart for the last time.
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After the front subframe was finish welded they put it back into the chassis (raw), installed the steering rack, mocked up the steering shaft with the new forged U-joints, and shop manager Brad shot the pics below. We will keep the fabricated bits in raw steel until after the initial road & track testing is completed, so if we need to make any changes we're not grinding a powder coated finish off to add something.
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Last week Ryan removed the rear subframe assembly from the car (at that point still just tack welded) and got to work finish welding that. As with the front subframe, he added gusset plates here and there, boxed in a lot of structures, and TIG seam welded everything as he went. He also built several welding fixtures to keep everything straight and true during welding.
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He's finished with the bulk of the work on the rear subframe now (we will still add a reinforcing plate or "X" tubular structure to the bottom - he adding mounting tabs for this) and the project is just awaiting a big shipment of parts before we jump to the next step. We have put a few teaser pics out there during these various fabrication steps and people have really liked what they have seen, and we even have people already in line for these kits. So yes, we're going to have to produce all of this in kit form. It might end up a bit pricier than other kits out there, so we may make them in pretty low volumes, but this will not be our last V8 Miata.... no no no.
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What's not to like? The weight will still be at or under 2500 pounds, with a 6-speed capable of taking 700 ft-lbs of torque, the motor we have for this will make 450+ whp and you can make 600 whp on pump gas with a little bit more spent. We're upgrading ALL of the weak points of NB Miatas and previous V8 swaps, with the move to C5 spindles/wheel bearings and the rear hubs we've used. The Ford 8.8" aluminum IRS center section is super stout and has lots of LSD options. Its going to be a potent little beast.
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So that's what we have been up to on this Alpha Miata V8 over the past 5 months: we tweaked and measured the RX8 bits, made a brand new front crossmember, chucked the RX8 bits, made another all new front suspension with Corvette spindles and brakes, made a T56 possible without cutting the tunnel up, finish welded the tubular subframe assemblies on both ends, finish welded the custom suspension bits, and everything so far is a bolt-in (except the two notched sections at the back of the engine bay). Should be kit-able. Should be fun.
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What's Next?
The flywheel, clutch and bellhousing are ordered and should be here in the next week or two. Same goes for the final front engine accessories and brackets - the borrowed set shown is already back on the FR-S. The next big step is fabricating the full length stainless headers.
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Left: Vorshlag built full length prototype headers for Scion FR-S LSx. Right: Production CNC bent stainless headers for Vorshlag BMW E46 LSx
We finished the custom prototype set of full length headers about 6-8 weeks ago on the FR-S and last week we tested the 2nd production iteration, and its almost perfect. Making the prototype headers, bend by bend, is a tedious process. We use a few tricks (the plastic snap-together bends help mockup) but it still takes more than 40 hours to make the first set. With materials and our shop rate that would be over $5000, which is crazy - but that's what one-off set of stainless full length headers cost for a V8. Of course we will we have the prototypes transferred digitally in 3D, then have the tubes CNC bent, and production headers made in batches of about 10 sets - which pulls the retail price for these swap headers down around $1700.
Seems like a lot until you consider that these are very low volume production parts made for an engine swap, unlike typical high volume "store bought" headers. These are also made from real 304 stainless, have proper merge collectors and V-bands, and are 100% made in the USA. The full length 1.75" primary design tends to add about 40-50 whp over stock manifolds or block-hugger style headers. And proper full length exhaust headers like these adds "guilt free power" over manifolds or shorties, with no downsides. These will add power to low, middle and upper RPM ranges alike. In our experience, the myth about "long tube headers killing torque" is utter nonsense. No, they won't be Tri-Y designs, nor will the primaries be perfectly equal in length, they will be the best headers that can fit the confines of this chassis/subframe/engine, with the least number of restrictive bends - that works better than "equal length" headers with tons of unnecessary, tortured bends. :)
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We still need to make the driveshaft and halfshafts, then pick the final wheel sizes and get those built to order on the car. We will re-drill the rear hubs to match the fronts (rear is Ford 5-lug, front is GM 5-lug; our new CNC mill will make quick work of that). And we still have to do the cooling, and plumbing, and wiring, and fuel. It seems daunting but honestly, the hardest parts of this swap are behind us - the all new subframes and custom suspension arms were the BIG development hurdles on this project. You will now see a lot of what we learned on previous BMW V8 swaps and the current FR-S V8 swap on the rest of Miata, and those V8 swap experiences over the past 12 years will help us get this one to the finish line. The Miata swap is much more extensive (since it needed hubs, suspension, diff, and entire subframes) than others in the past we have built, which has made this one take us a bit longer than we'd like - but doing it right takes time.
A lot of folks keep asking us - when will this be done? And my answer is - its done when its done. The owner of this car has been extremely patient, but when you are an Alpha customer for a new swap like this, the shop ends up eating $20-30K+ in labor for the first build (hundreds of hours of research, testing, trial/error, fixturing, and hand built fabrications), so that's what their patience nets them.
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Once the wheels and tires are picked and installed we can make some flares to cover the (likely) 285/30/18s at all four corners. We just went through this work on my TT3 prepped 2011 Mustang and Ryan built some beautiful metal fender flares to cover 335mm front tires (which go with the 345mm tires and rear flares the car already had). We can do the same work on the Miata, no problem. The owner of the car, Jason, is picking up a fiberglass front end that should work better with the wider track width and we'll tie the flares into that.
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And YES, one more time, we plan on making a kit for all of this - tubular front subframe, tubular rear subframe for 8.8" Ford IRS, control arms, motor mounts, transmission crossmember, driveshaft, halfshafts, uprights, hubs, steering shaft, and headers - on the first round of swap part releases. Much more will be developed after that "Stage 0" round of major parts is in production (like plumbing, cooling, wiring, and fuel system solutions). These bits will only be available after this car is road tested. We will post up a few more times before that happens, so just subscribe to this thread and you'll be the first to know. That's how we've done all of our BMW kits (120+ kits sold) in the past - get a car built, then release the major drivetrain related mounting bits + headers, then release the sub-system solutions after that.
More soon,
Project Update for November 11, 2015: It has been a long time since my last update on the Alpha Miata LS1 swap build thread, so we have a lot to cover in this update. This project was on hold for a while, but was put back on the schedule in July. Since then the front and rear suspensions were wrapped up enough to put the car on the ground, wheels and tires mounted and tested, bodykit mocked up, engine's intake and accessory drive finished, and more.
https://vorshlag.smugmug.com/Project...DSC_7450-M.jpg
Our first LS1 powered Scion FR-S (shown above right, next to the LS1 Miata) was completed enough for the customer to start driving it during that 6 month hiatus in the Miata project, and we developed some new things on that swap that will help us on the Miata. The FR-S recently came back for some follow-up development and I will update that build thread soon.
Difficult Realizations
There were many things going on behind the scenes that held up progress on this build for the first half of 2015. Obviously this project has moved beyond the original scope, because it became much more than just a "bolt in swap kit".
As we moved from section to section and addressed the weak points, the project began to fall well outside the realm of just a V8 swap kit. We were dedicated early on to removing all of the weak links that we often see fail with track abuse in other V8 Miata swaps, namely the front hubs and rear hubs, the rear halfshafts, as well as the need to upgrade the OEM brakes and control arms to deal with massive engine torque and tire grip. Addressing those issues in a kitable format was going to take serious added engineering and fabrication hours, more than we could every hope to recoup with kit sales. So the decision was made to do this car as a one-off, making both the engineering and fabrication easier and saving hours and hours of unbilled development time.
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The customer and I had a good conversation in late June, after we both did some research into other Miata V8 swap costs. This is when we realized where reality was: With many turn-key swaps for V8 Miata's costing $50K (minus the chassis), our revised numbers for a one-off build didn't look so far out of the realm of possibility. We all agreed to some compromises and then moved forward. This delay ate up several months this year but we were back on track late this summer.
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Does that mean we will no longer offer the finished work in kit form? After a hard look at the costs, I doubt it will be at a price point most people will want to pay for a home-built swap kit. Of course we can replicate these parts on the Alpha V8 Miata as a turn-key installation for others. Will it be cheap? No, but it won't be out of the range of other turn-key Miata LS1 swaps.
I feel that the end result will make for a pretty durable and damned fast track car that can still be street driven. It might end up being the only Miata V8 ever build to this level of insanity (this customer asked for "crazy"), but that's not necessarily a bad thing either. Let's look at some progress!
Rear Suspension Change and Major Progress
The final steps of finishing the rear suspension were pretty tricky on this car. Due to some challenges we had to think outside the box to get to the finish line.
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We have taken a car made for small brakes, small halfshafts/hubs, and small wheels and tires and jammed a massive 8.8" Ford diff in there, big aluminum uprights from a RWD V8 powered production car, and are building all of this around an 18x10" wheel and 285/30/18 tire out back.
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Once the custom upper and lower control arms were built and the halfshafts mocked up, it was clear there was not enough room for a coilover rear shock and spring in the normal location. We tried it upside down, right-side up, moving the upper and lower mounts this way and that - no chance. The rear suspension upright layout we are using made it impossible to fit the spring and shock there.
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It was just a matter of space - there wasn't enough of it. So I decided to change the rear shock layout into a pushrod/bellcrank style, and move the spring and shock into the trunk. What the what?!
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This took a lot of work - mock-ups, calculations, CAD design, CAM programming, CNC machining, fabrication, and testing - but it is in place and we now have the shocks mounted in the trunk. The suspension moves up and down and all of the motions look good, and everything is overbuilt and strong.
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A big chunk of billet aluminum was used to make the pair of bell cranks in multiple steps on the CNC mill, which was a good use of our new CNC machines and skills that we added in January 2015. We bought CNC machines to make ALL of our production Vorshlag components in house, but this also allows us to make custom one-off things like these Miata rear bell cranks.
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We didn't go to pushrod actuated inboard suspension to be cute, but out of necessity. The bigger, stronger rear suspension and driveline parts we felt were warranted in this V8 build just ate up too much room, and we had to spend more hours to move things around (most of which were unbillable development hours).
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I will go into more details on this rear suspension once we have done some road testing, but so far I'm happy with the results. The bell cranks were CNC machined in custom fixtures over 3 operations to make the completed bits. Radial ball bearings were installed for the pivots and rod-ends are attached at each end of the bell crank - one to the pushrod and the other to the shock.
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The front shock we had already built was used for the rear mock-ups and the length/stroke were pretty spot on for the rear, with the motion ratio of the bell crank and pushrod location on the rear control arm.
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The rear control arms had double-shear pushrod mounting tabs added, then the pushrods were built, and the whole setup was then tested through the full range of suspension motion. Once that was confirmed the rear control arms were final welded.
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We have fixed length mock-up rear shocks in place for the moment, but another pair of Bilstein ASN coilovers will be built to wrap up the suspension soon. Now we can at least check ride heights on the ground, start tire mock-up, and move forward on other systems with what we have in place.
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The fuel filler neck will be relocated inside the trunk at the left corner, to leave room to load luggage for use on road trips. This car will not carry a spare tire, so some of the brackets that are used to hold the jack and temporary spare will be removed to add some much needed trunk volume.
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The rear shock mounting is probably the craziest part of this swap, but again, it was the right solution for the constraints we had.
Engine Completion Work
The built LS1 longblock that we have had in place for a while was finally dressed out with many missing intake and front accessory parts in recent months. First up was the coil packs and brackets, which were purchased, assembled and installed.
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There are a number of various coil packs and coil pack sub-harness ends made for GenIII and GenIV LS series engines, but if you order the main engine harness correctly, it doesn't matter which you choose. We went with F-body brackets, sub-harness and coil packs. These bolt to 1999-02 Camaro LS1 valve covers, where I used button head stainless M6 bolts to hold them in place.
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The LS2 intake manifold and throttle body were installed next. I explained in detail why we used an LS2 intake and throttle body on the Alpha Fr-S in THIS POST, which you can go back and read - because it also applies for this car. Basically the LS2 manifold has the same cathedral port shape as the LS1 heads on this motor, but it has the "short" drive-by-wire throttle body needed to clear the hood. If we would have used an LS3 motor the LS3 intake manifold and throttle body would have been the obvious choice. Cable operated throttle bodies are much longer and would not clear the hood line.
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The front engine accessories and their mounting brackets were also finalized and installed. This car is being built without power steering, and we had originally mocked-up Pontiac G8 LS2 accessories - the same that the Alpha FR-S LS1 used - since that car has electric steering. These cars have very different engine bay shapes and widths, and on second look the 4th Gen F-body LS1 brackets, accessory layout and front drive pulleys were more appropriate, so we went that route instead.
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A new water pump, alternator, brackets, tensioner and idler pulley were procured, along with GM sourced hardware to attach all of this. I will show more details on the serpentine routing to bypass the power steering once the harmonic balancer/lower pulley is here (ordered weeks ago but on backorder), but the picture below shows the normal 4th gen LS1 belt routing - with the power steering pump in place. We have already changed the smooth idler pulley to a 6-ribbed pulley, which I installed with an 1/8" spacer to line up to the main belt "plane". Saw this on Yellow Bullet - those drag racers don't need no dang power steering. :)
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Long story here (back ordered part), but we're waiting on the correct SFI-rated front harmonic balancer and pulley for the 4th gen Camaro belt placement (there are 3 or 4 different belt placements for LS engines, front to back). The one we have installed now (shown below) was for the G8 accessory belt offset, which is about 1" too far back for the F-body accessories.
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Rear Wheel Hubs Modified
The rear suspension uprights we used are a popular Ford Racing part made from a production Ford vehicle, and it is often use on Cobra Kit cars. These are made for Ford hubs, and we used the 31-spline 2003-04 Mustang Cobra hubs, which have a 5 x 4-1/2" bolt circle (5 x 114.3mm). This was a proven, durable, and readily available package. This Ford rear flange made perfect sense when the front suspension were going to be based around Mazda RX8 hubs/uprights/control arms. Ahh, the early days of this project were so simple...
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Now we have Corvette front uprights and hubs, which use a GM 5 x 4-3/4" bolt circle (5 x 120.65mm), which doesn't match the rears. When we moved to the Corvette spindles we planned on modifying one end or the other so that the bolt patterns would match, and now was the time for this change.
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The guys removed the rear hubs from the uprights and Jason machined a custom set of soft jaws for the CNC mill to secure them in place. Then he installed the first hub, zero'd the machine on the hub center and face, programmed 5 new holes on the GM 5 x 4-3/4" bolt circle, and drilled them with the CNC. Instead of the pressed-in "splined" wheel studs that were used before (Ford still uses 1/2" stuff), we made these for screw-in wheel studs in a GM thread pitch and diameter...
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Once out of the CNC vice, Jason tapped the newly drilled holes in both hubs for M12-1.5 thread pitch, then Olof installed Vorshlag 90mm wheel studs made for a BMW. We have these wheel studs made to our specs and sell thousands every year. GM and BMWs use the same stud and lug nut diameter and thread pitch (M12-1.5). Proven, tested, safe. Yes, they are long, but if we ever need to use spacers we have the room. This car can also be used in Gladiator races.
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A drop of red Loctite is used when torquing these 90mm studs into the hubs, just like when installing them in BMWs. When installed correctly we can "zing" lug nuts off with an impact gun, with no issues. The completed hubs were then installed back into the rear uprights and the assemblies went back into the rear suspension. Now its time to mock up some GM bolt pattern wheels!
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Ugly. I first tested with some C4 Corvette 17x9.5" wheels and 275/40/17 tires (the OEM wheels that were on my 1992 Corvette when I bought it). These are much taller tires, the wheels had the wrong offsets, and were not useful in mock-up at all. We looked around the shop and then found the perfect set to test with - which would allow us to drop the car on the ground for the first time in a LONG time...
https://vorshlag.smugmug.com/Project...DSC_9035-M.jpg
Down on the Wheels + Flare Mock-up
This was a big step just a few weeks ago, with the Miata placed down onto some decently sized wheels and tires with the new custom front and rear suspension setups. Damn happy that this car now rolls...
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This time Ryan installed the race wheels and tires from my NASA TTC classed 1992 Corvette race car. Due to class restrictions we run that car on a 245mm tire (Hoosier R7), but its a BIG 245, with 9.7" of tread width. These tires are mounted to some lightweight SSR 17x9.5" wheels with a GM 5-lug bolt pattern. The mock-up tires (245/40/17 Hoosier) are still too narrow for this car's power level, but they were 24.3" tall and somewhat similar in width to what we will end up with (285mm on 18x10" wheel).
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The Miata's owner provided this wide body kit, which is a fiberglass reproduction of a popular NB flare kit. It has 4 flares, a new composite nose (not yet fitted) made for NB2 headlights, and side skirts to tie it all together.
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https://vorshlag.smugmug.com/Project...B61G4372-M.jpg
The styling of this kit looks odd in these mock-ups, but once painted and "fitted" they work fairly well. The race car shown below has the same kit. We saw this at a recent track day at MSR-Cresson and it used 275/35/15 Hoosier race tires on 15x10" wheels, which is super short (23.0" tall) and easy to fit onto these cars with this body kit.
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Ultimately we're still shooting for a 285/30/18 tire and an 18x10" wheel. Why not go with the proven 275mm 15" Hoosier that fits this body kit? Two reasons. First its narrower, but more importantly there are ZERO street tire choices in this size or anything close to it. There is a Hoosier race tire and... nothing else.
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The 285/30/18 tire shown above is fairly popular for racing use and gives the owner over a dozen choices in street tires + several DOT-R race rubber choices as well. We will have to modify the front frame horns for the taller 24.9" diameter tire, to have adequate bump travel, but we always knew that. This 285/30/18 size is really the best option: super short for the width and wheel diameter it has, with a lot of tire choices.
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And yes, the images above shows the Miata and the 17x9.5" wheels with some serious "poke" past the front flares. The front and rear tracks were measured identical here, but the body kit's flares have much wider rear flares than front flares. Still, we managed to address this issue earlier this week, by adding some much needed front negative camber. See below.
Front Suspension Progress
The initial suspension measurements and mock-ups were done "in the air" but once the car was sitting on all 4 wheels and tires at ride height, it was obvious the front needed a tweak to the upper control arms to get the static camber settings in the right range.
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These were the last arms to be final welded, and were only tacked in place. It was assumed that there might be some adjustment once at ride height. The upper arms were removed, shortened, mocked up then final welded earlier this week.
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The car now has -3° camber front camber and adjustments to go up and down from that range. Side benefit - which we knew would happen - is that the front tires now fit under the flares much better.
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Next we will measure the existing 17x9.5" wheels and look at how far we can go inboard with an 18x10". Then we will order up some Forgestar custom 1-piece wheels in this size and add some 285/30/18 Hoosier A6 tires that were acquired for mock-up use.
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The Miata will eventually be built on 285/30/18 tires from the new "magic" 200 treadwear sticky street tire options... but instead of buying those NOW, it makes more sense to wait until closer to completion, as tire options and supplies change every quarter. Who knows what uber-tires will be introduced in a few months for 200 treadware tires? There are Tire Wars in process! :)
What's Next?
We have the supplies on hand for making custom headers, supplied by Magnaflow. These 1.75" primary mandrel bends, 3" collectors and LS1 flanges will be used to make the headers soon.
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The driveshaft has to be built first, so the headers and exhaust can route around that. Some Miata "rail stiffeners" and a "butterfly brace" will be added first, to make sure everything routes nicely together - braces, driveshaft and exhaust.
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Rear brakes are also being address very shortly. C5 Corvette rear brake rotors (see above) were ordered and should be here any day. We already have C5 rear calipers and pads and plan to make brackets to mount these to the rear uprights that are in place. Then we can move onto plumbing the brake and clutch hydraulics, have the wiring harness built, and more.
More soon,
Project Update for April 28, 2016: It has been another long break since my last update on this Alpha Miata LS1 swap build thread, but we have made a ton of progress since then. We have so much work to cover that its going to take a number of installments, but I've been buried with work and am behind on the build thread. One thing I wanted to point out - this is not going to be made into a kit, because it would be so costly as to be unattractive to almost everyone. We cut that goal shortly after my last post and that sped up this build considerably.
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In the next handful of updates we will cover the custom exhaust headers, the custom DSS rear axles, custom driveshaft, we switched transmissions (again!), made a customized shifter and trans tunnel cover, installed the Air Con, ordered and installed the wiring harness, removed the fuel tank and started plumbing that system, custom built a radiator and installed that, built all of the cooling hoses, mounted a remote coolant reservoir, mounted the C5 rear brake calipers, built the remaining two shocks and installed the springs, added a C6 electronic throttle pedal, modified the booster to mount a C5 brake master cylinder, made an adapter to fit a Tilton clutch master cylinder, and dug into the wiring of the motor and gauges. We also spec'd 18x10" Forgestar wheels, got those in, and mounted 285/30/18 Hoosiers (tires only being used for mock-up and fender mods). Whew! Lots to cover, so let's get going with the first update.
MORE TRANSMISSION FOLLIES
One of the things that happened right after my November post was a change of transmissions... This project has been a real ball buster with respect to the transmission! The initial desire on this swap was to avoid the transmission tunnel mods needed in other V8 swap kits. This seemed like an extra burden that would prevent DIY mechanics from doing this swap at home, and in fact that has been a common complaint from many V8 Miata swappers. Funny enough, none of this matters now that we blew off the "kit" plans.
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Still, hacking up the tunnel seemed unnecessary to me if we were willing to make a custom front crossmember - which we did, and that added LOTS of room to move the engine lower than the kits out there. Modding the tunnel would mean removing the entire dash and interior, cut and slice the floor pan, weld in some new sheet metal, then stitch weld that all back together to clear the T56 - as is done with the other V8 Miata kits. We thought a move to the Tremec TKO 5 speed would be beneficial and tried that... but ran into some packaging difficulties. Then we tested a 4th gen Camaro T56, and that worked, so we built the kit around that.
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4th gen F-body T56 and bellhousing attached to the final LS1 engine
After we had the engine mounts and crossmember developed around the 4th gen T56, we ordered a brand new T56 Magnum. Now this term "Magnum" is bandied about freely, but there are a lot of definitions of a "T56 Magnum". This is where a mistake happened... and damn it, I know better.
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This is the real T56 Magnum, brand new and available from Tremec for T56 applications...?
New T56 Magnums are the unit shown above, available from Tremec, which has a different front to back length and different shifter location than a 4th Gen F-body OEM T56 (1998-2002). Those differences are big but are NOT clearly shown in their catalogs. These are images of the two T56 models and they don't even measure them the same way.
The T56 Magnum version is stronger and more readily available - the 4th gen F-body T56 has been out of production for going on 7-8 years. We tend to use T56 Magnums in our BMW V8 swaps, but it only requires a driveshaft change. Otherwise you end up hunting in junkyards for F-body length T56 units, but they are so old by now they all have to be rebuilt... in the end you spend more rebuilding an old T56 than buying a new T56 Magnum.
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There are many shops, however, who sell upgraded F-body T56 transmissions as a "T56 Magnum" edition. They are dimensionally different than brand new T56 Magnums made by Tremec... and often have different input or output shaft lengths and spline counts. We get customers ordering the wrong BMW V8 swap driveshafts because of this "Magnum" name being mis-used.
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What these two Tremec catalog charts don't show is that the location of the shifter is very different between the F-body T56 and the T56 Magnum. Notice how "A" is measured differently in the Tremec catalog? Well this is a real mess that Tremec should fix in their literature, but they stopped selling the F-body T56 about 6-7 years ago and its not been listed in their catalog since 2009.
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Left: The T56 Magnum shifter location is too far forward (inside the dash!). Right: 4th gen T56 is much better!
After we received the new T56 Magnum our crew installed it into the car. I looked in the stock shifter hole (above left) and saw that it was waaaay too far forward. Not good. I admit to uttering a few choice words. The T56 Magnum has a shifter location that is about 3" farther forward compared to the 4th gen. Again, I had figured this out in 2008 but somehow forgot this key piece of knowledge. In the BMW V8 swaps it never mattered much (there was plenty of wiggle room in the tunnel/console). On the Miata the Magnum shifter base is inside the center stack of the dashboard, so I had to punt.
I took a used 4th gen T56 mock-up transmission I had in the shop and asked our friends at Dedrichs Motorsports to completely rebuild it.
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Now this T56 brand new, upgraded, and most importantly - has the shifter in the right spot! It has a new input shaft, main gear cluster, synchros, and all new bearings and seals. Even most of the gears had to be replaced. Using the T56 Magnum with the as-built shifter location would just not work - we would have had to move the engine back about 3 inches, which would require serious firewall and tunnel mods that nobody was keen to do.
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Oh well, live and learn. This one is 100% on me and I had to eat the cost difference between the two T56s (and some labor hours), but we will use the T56 Magnum on another V8 swap project we will tackle soon. At this point we could at least move forward with the custom exhaust header development, driveshaft construction, and exhaust system layout. The T56 debacle held us up for a couple of months but Joe at Dedrich's Motorsports went through our old T56 and made it a new monster inside.
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I'm skipping ahead a couple of months here. We purchased the Hurst 6-speed for the 1998-02 Camaro T56 and put it in the car, knowing it would likely need to be modified at the base, handle and such. The Miata trans tunnel opening had to be notched a bit on the leading edge, too.
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To cover up the now over-sized transmission tunnel hole Ryan made a piece of aluminum plate to fit, which bolts to the tunnel and is notched to clear the Hurst shifter and adjustable 3/4 shift stops.
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The shift handle was still too far forward so Ryan modified both the base and the handle to offset them rearward and angled back towards the driver. This made the shifter fall closer to hand and eased the interference with the stock center console opening.
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We also ordered a Joe's Racing fire proof/Nomex shift boot and frame, which we install on virtually any car we build with a V8 swap. This helps seal up any opening in the tunnel, to make that opening fire proof and to reduce heat and noise transferred to the cabin. These come with an aluminum frame that has snaps built around the edge and the Nomex boot snaps over that. In the above right picture I pulled the shift boot down over the modified handle for the picture, but it slips up and has a velcro connection to close the gap around the shaft.
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Here's a picture of the same Nomex shift boot added to my C4 Corvette recently, as well as some thermal / radiant barrier near my leg (no interior to shield heat from exhaust/trans). It can be used to completely replace a factory boot, or like we did here, go over the factory rubber tunnel seal. In the Miata it is under the factory leather shift boot. Regardless - its a GOOD IDEA to add one of these ~$90 fire proof shift boots to any race car or any car with a modified tunnel opening.
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continued from above
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The original factory shift boot was old and torn so a brand new Mazda sourced leather shift boot was purchased. This is going to be street driven and have a full interior, of course. This Nomex shift boot will all be hidden under the leather boot. Other than that, the transmission just needs a shift knob and some fluid, plus the reverse lockout wiring and speedometer connection.
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Once the transmission was in the car and finally "locked down" the driveshaft, so that could be spec'd and ordered. We got it about a week later and installed that.
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That was installed for fitment checks and exhaust routing, and it looked perfect. Big 3.0" diameter aluminum unit rated for 600 hp, so it should be fine with 475 whp.
BRAKE WORK
Shortly after my last post the C5 Corvette rear rotors arrived. These are StopTech/Centric Premium blanks (the "Premium" version gets you powder coated centers instead of raw cast iron - no rusting) which are 12.0" in diameter and 1.0" thick, which are the same rear brakes on all C5 generation Corvettes (1997-2004), from the base models to the Z06.
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When we had the rotors in hand and the rear hubs re-drilled for the GM bolt pattern Ryan mocked up the C5 rear calipers and brackets (above). Making the actual bracket to mount these correctly didn't happen until several months later. Initially we were going to measure then CNC machine these on the mill, but our machines and engineer are so tied up making suspension products it fell onto Ryan to fabricate these in April.
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First the calipers, pads and slider brackets were mocked up on the rotor and aluminum upright, on the fab table.
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Then came hours of measuring, cutting, welding and juggling of thicknesses to get the calipers mounted in the right radial and lateral positions relative to the rotor.
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Other than the flex lines to connect to the rear hard lines, this C5 rear caliper / C5 rotor / 03-04 Cobra rear hub swap is done.
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Since the front brakes are C5 and the rear brakes are C5, I had the obvious idea of ... using a C5 Corvette brake master cylinder to actuate the calipers. Kind of a no-brainer, right? I asked the guys to yank the Miata brake master off and I did some measuring...
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We had a C5 in the shop and the stock C5 master looked dang close. So I ordered a C5 master cylinder as a test...
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Sometimes I'd rather be lucky than good! All it took was shortening the "stem" from the booster/pedal and just a kiss of hole enlargement on the C5 master cylinder mounting flange and it slid right into the Miata booster. Win!
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Now that the brake master was handled Ryan tackled the task of adapting a Tilton master cylinder to the firewall for the clutch hydraulics. Yea, its not "Brake system" but its pretty close, so roll with it.
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Just like on the FR-S LS1 swap, Ryan made a billet aluminum adapter to go from the firewall bolt spacing of the Miata clutch master to the Tilton mounting flange. He made it so fast I never got a picture, so the pics of FR-S parts above will have to do (similar in design).
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Once the firewall adapter and pushrod changes were made the Tilton clutch master cylinder was functional. This will change the hydraulic ratio of the clutch circuit using a larger diameter master cylinder that we've used in the past and know works with the clutch we're using.
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That's the firewall line-up with the Tilton clutch master, firewall adapter, the C5 brake master. There's wiring and fuel system plumbing shown, but I wanted to keep this post short and sweet so I will cover that and MUCH more next time.
Thanks for reading!
Still Terry @ Vorshlag
...so an Admin has somehow jacked up my original account here. If I try to login as "Fair" the site gives messages like "food in I/O port" or "server busy" or redirects me to LadyFootlocker. ;)
While that's pretty funny, if the owner of this site wants to boot me off, just say so. Or step up your Troll Game. :)
Still Terry @ Vorshlag