Vorshlag Miata LS1 Alpha Project

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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.



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.



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.



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.



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.


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. :)



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.



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.



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,

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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.



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.



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.



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.



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.



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.



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?!



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.



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.




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.



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.



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.



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.



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.



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.



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.



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.



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. :)



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.



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...



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.



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...



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.



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!



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...



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...



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).



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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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.



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.



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.



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.



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.



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.



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.



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.



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.



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,

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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.



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.



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.


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.


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.



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.



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.


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.



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.



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.



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.



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.



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.



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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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.



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.



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.




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.



First the calipers, pads and slider brackets were mocked up on the rotor and aluminum upright, on the fab table.



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.



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.



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...



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...



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!

continued below

[StillFair]

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.



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).



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.



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

[StillFair]

...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