Turbo or Supercharger

[Rob®]

Just as a heads up, I would very highly suggest you add a proper water temp gauge to your cooling mod list. It doesn't do anything in the way of actually cooling, but it is pretty much vital. Of course you need to actually know what temps are too high.

I would suggest to add an oil cooler to the list as well, but that might be my overkill kicking in. Also more for a turbo; I'm not sure how hot the oil gets on a SCed car. I forgot to mention that in my other post, sorry.

[MoonieGT]

The rotrex has it's own oil system, which is nice. No tapping into the stock system. Oil cooler and temp guage sounds like a good idea to me. Thanks for the info Rob. It'll be a year or two before I pull the trigger on something, but I'll start the cooling mods over the next few months...

[SirHustlerEsq]

My turbo car is 100% reliable on the track, no chasing loose hardware, no overheating, fast as hell, and a real pleasure to drive. The last time I checked, any turbocharger was more efficient (produced less heat) than just about any supercharger, they also produce similar EGT's at similar output levels.

I *just* did a coolant reroute the last time I tore my setup apart - I actually have yet to fill it with coolant since I bolted it all on - and I have plenty of track and street time on my motor with no damage from lack of coolant reroute with years of high boost. Obviously I have yet to compare water temps before and after, but I have never overheated without the reroute (and my gauge reads actual temp). Again, by theory alone, heat is your enemy, so a coolant reroute is a great idea. You can argue if it's "needed" but it's not a bad idea by any means.

You won't see a shift in water temps because that's not how the reroute works, it moves water through all sides of the motor, not just around the first two cylinders.

What else does the car need to withstand track days? Radiator upgrade, IC, coolant rerout, ect? Can you track a SC miata with no IC at 5-6 psi or is that a formula for disaster? My car has an upgraded exedy clutch in it from the PO by the way...

TDR has the formula, no need to debate this.

Just as a heads up, I would very highly suggest you add a proper water temp gauge to your cooling mod list. It doesn't do anything in the way of actually cooling, but it is pretty much vital. Of course you need to actually know what temps are too high.

I would suggest to add an oil cooler to the list as well, but that might be my overkill kicking in. Also more for a turbo; I'm not sure how hot the oil gets on a SCed car. I forgot to mention that in my other post, sorry.

I like my "real" water temp gauges, VEI makes cool stuff two and you can get 2-gauges in one spot.

Why "more so for a turbo"? The volume of oil flowing through a .035" hole through the turbo is hardly going to affect oil temps on the gallon in the sump. I see the same oil temps as supercharged cars with the same oil coolers. I also don't think the oil cooler is a suggestion, its a requirement. I saw 270*f oil temps in John's 130whp NA Miata at Hallett last month.

[Titus]

The Rotrex looks nice, but you won't have local support. This gives the TDR systems a big advantage in my mind. There is a lot to be said for knowing you can drop the car and credit card off at Track Dog Racing if you get in over your head with a problem.

[MoonieGT]

I could certainly be wrong, but from what I've read the outlet temps on the Rotrex are lower than PD blowers and turbos.

[Titus]

My turbo car is 100% reliable on the track, no chasing loose hardware, no overheating, fast as hell, and a real pleasure to drive. The last time I checked, any turbocharger was more efficient (produced less heat) than just about any supercharger, they also produce similar EGT's at similar output levels.

I don't believe that was always your experience. How much money has it taken to get it to that point?

[MoonieGT]

The Rotrex looks nice, but you won't have local support. This gives the TDR systems a big advantage in my mind. There is a lot to be said for knowing you can drop the car and credit card off at Track Dog Racing if you get in over your head with a problem.

That is true. I'm *hoping* the simplicity of the Rotrex system will prevent me from getting in over my head. However, nothing is ever as easy as it seems. TDR tech support would be pretty invaluable...

[Rob®]

I don't believe that was always your experience. How much money has it taken to get it to that point?

Exactly. My chasing loose bolts and things was experience with my FM2 kit...which has been off the car for years. Sorry I was not clear on that. Between moving every few months and changing turbos and complete setups on my car, I have not been on a track with a setup I made more than a few times in the last 4 or 5 years. When I have, the car ran flawlessly. Knowing MoonieGT wants reliable low power, I still firmly believe that a supercharger is his best bet. Sure he can overbuild the hell out of a low boost turbo setup for his power goal, but why? All that money spent for a dead-nuts reliable 6psi setup? Seems foolish to me, and I love turbos.

[cwisenheimer]

If you would like a mostly unbiased professional opinion on a Rotrex vs. a PD s/c, you might give Corky a call. He can give you reasons other than marketing or licensing to choose one over the other. Technical merits aside, I'm with Titus on the local support idea if you choose a supercharger.

[SirHustlerEsq]

I don't believe that was always your experience. How much money has it taken to get it to that point?

Well, that's somewhat accurate. Now there are Inconel studs made by Track Speed Engineering made specifically to address this and if that were available at the time I would not have thrown the baby out with the bath water on the BEGi kit and done the AF kit. The AF parts cost me $1200 in DP and manifold, $600 for the FMIC, $400 for the welding, then $900 for the WG/BOV/turbine housing...roughly $3500 all said and done for the mechanical turbo stuffs...and the motor can make 300+whp on a Mustang dyno.

90% of the other parts on my car like the huge radiator, oil cooler, 6-speed, 3.63, and Ms would be there if I had a blower too.

The moral of the story is simple though, I've driven lots of supercharged cars like Gary's red car and its fast as hell, and just as reliable as mine...I still want to drag race that car.

[SirHustlerEsq]

Exactly. My chasing loose bolts and things was experience with my FM2 kit...which has been off the car for years. Sorry I was not clear on that. Between moving every few months and changing turbos and complete setups on my car, I have not been on a track with a setup I made more than a few times in the last 4 or 5 years.

Sorry to sound condescending; my personality doesn't cross over on the interweb very well.

Exactly. All that money spent for a dead-nuts reliable 6psi setup? Seems foolish to me, and I love turbos.

I agree, if someone's going to spend $2k, make 250whp and get the most for your cash. 200whp is boring.

As to why an oil cooler is "more for a turbo": pretty simple - a turbo is oil cooled from the sump oil - a supercharger is not. Yes, a tiny amount of oil cools the center section, but any drop in temp of that oil is a good thing. I did notice a nice difference in measured temps (via a sump-mounted temp sensor) with and without my oil cooler, how about you? How does that work, going by your tiny hole theory? I thought I made it fairly clear that I don't have experience with superchargers, so their oil temps are unknown to me. So thanks for pointing out they are the same temps as a turboed car.

It's not really a theory, very little oil goes through the turbo considering the orifice is smaller than a pencil lead. Aside from that, who is using non-water cooled turbos these days aside from drag racers? My oil temps broke 280*+ on street driving from 5th/6th gear pulls before installing the oil cooler. My oil temps are still bad, but hopefully moving the oil cooler this weekend will get it down to where I want it.

I know how a coolant reroute works, thanks. I also said that I have no damage from not having one for years. Then I went on to say that it's a good idea to have one. But really, I'm glad all you got from what I said about them was that I did not measure a difference in overall temperature.

I had a front and rear water temp sensor initially and measured a very large drop in rear head water temps. On the 1.6 at 86whp I would hit 180* front temp and 220* rear temps back when I was learning MS on the 86whp 1.6.

[Rob®]

The moral of the story is simple though, I've driven lots of supercharged cars like Gary's red car and its fast as hell, and just as reliable as mine...

I think you missed the entire point though. MoonieGT does NOT want a car that is fast as hell. He wants a set-it-and-forget-it setup that makes fairly low power each and every time he gets on it. Spending all that money and time to have a completely custom bulletproof low boost turbo setup is not the smartest use of money, when he can spend the same (or less) with a bolt-on supercharger kit and be done with it. He will have loads of support if anything goes wrong with it, since it is not custom, which is worth a good amount on its own.

If he wanted balls out power now or later, I would fully agree to spend the money on a track-capable turbo setup. But he doesn't.

[Rob®]

Sorry to sound condescending; my personality doesn't cross over on the interweb very well.

Same here, so noted.

I agree, if someone's going to spend $2k, make 250whp and get the most for your cash. 200whp is boring.

Again, agreed. But MoonieGT does not want that. *That* is why I said a supercharger would be best for him. Not anyone else; him, in his particular instance, going by what he said his goals are. I am a turbo guy - always have been, always will be. For me to recommend a supercharger to someone, I feel, says a lot.

It's not really a theory, very little oil goes through the turbo considering the orifice is smaller than a pencil lead. Aside from that, who is using non-water cooled turbos these days aside from drag racers? My oil temps broke 280*+ on street driving from 5th/6th gear pulls before installing the oil cooler. My oil temps are still bad, but hopefully moving the oil cooler this weekend will get it down to where I want it.

The whole sentence about that that I retyped left a bit out. I originally typed something, then hit the wrong button and it all vanished. At that point, dinner was done, so I didn't bother retyping it all. Anyway, the gist was that my oil temps were relatively low pre-turbo and pre-oil cooler. I put the turbo in, and my temps skyrocketed. Makes sense. I put the oil cooler in and they went down drastically. Following a fairly simple thought process here, you added a turbo, a very very hot turbo, to the oil path. That HAS to heat the oil more than a supercharger, simply for the fact that the oil never touches any part of a hot supercharger. Is the difference 20°? 1°? I couldn't tell you. Regardless, you pointed out that SCed cars get just as hot oil, so an oil cooler is a necessity on them as well. Thanks for that bit of info, it is much appreciated.

I had a front and rear water temp sensor initially and measured a very large drop in rear head water temps. On the 1.6 at 86whp I would hit 180* front temp and 220* rear temps back when I was learning MS on the 86whp 1.6.

I would still like to know how you are saying there will be no measurable overall temp reduction after removing a metal pipe of coolant that was mounted to a hot manifold and inches from the turbo. I'm not saying it would be drastic, but I can't fathom how rerouting that pipe on the cold side would not have an effect on overall temps. I am VERY interested in seeing if that holds true. I kind of doubt it, but I'll take your word for it for now.

[MoonieGT]

There is some good info coming out of this, thanks guys. I don't have plans for max whp, I'm just after a staged approach. Start out with 180 or so and then figure out how the car is running. After I've gotten used to that at the track I'll worry about getting up to 220 or so. Thanks to you guys I've got a better idea of how to reasonably overbuild my car for my goals. I think I'll be looking at a bigger radiator and fans, oil cooler, coolant reroute to begin with. I'd like to make sure I'm not replacing new parts when I try to move up from 180 to 220.

[SirHustlerEsq]

Oil temp:

The volume of oil going through that orifice is so small that is has a very small impact on the gallon of oil in the motor. There's also a very large water jacket around the bearing; shoot the laser thermo on the water fittings and you'll see roughly 240*f on my car. The turbo also has a Monel turbine to dump heat and an Inconel heat shield between the CHRA and the turbine wheel to reflect heat away from the CHRA. If the oil were super-heated you'd see extreme shear in the oil which was common 20-years ago, but remarkably uncommon today.

The reason your oil temps were higher after installing the turbo is not because of the turbo oil stuffs, its because you doubled the VE of the engine and all that increase at the cost of increased heat from combustion.

Also, the turbo isn't much hotter than a header. Both supercharged cars and turbo cars see similar EGT's aside from the slight increase (~150*f) due to turbo back pressure because Xwhp on either car produce similar cylinder temps, its the 10lb of iron or steel on the turbo that functions as a heat sink.

[Rob®]

Correct. I know why oil temps went up when I put the turbo on - I never even mentioned oil through the CHRA by that point; I am very well versed in how/why turbos and motors work. I'm not arguing that the oil going through the turbo has very little impact on overall oil temp - in fact I said I have no idea what the difference it makes is. I even put a 1° change out there. What I am saying is that the fact that it has *AN* impact at all is why I said it was more important on a turbo car. But again, that was before you mentioned that SCed cars' oil gets just as hot. So yes, I admit I was wrong saying "I suggest you add an oil cooler" for a SCed car, instead of saying it is "required." I "suggest" people put them on NA track cars too, but that's generally me being overkill (apparently more overkill on the east coast if you're saying NA cars see 280° oil temps out here). I also flush my brake and clutch fluid before and after each track day, most people consider that overkill. So I guess it was my bad for saying "more for a turbo" sorry.

[jeepinbanditrider]

There is some good info coming out of this, thanks guys. I don't have plans for max whp, I'm just after a staged approach. Start out with 180 or so and then figure out how the car is running. After I've gotten used to that at the track I'll worry about getting up to 220 or so. Thanks to you guys I've got a better idea of how to reasonably overbuild my car for my goals. I think I'll be looking at a bigger radiator and fans, oil cooler, coolant reroute to begin with. I'd like to make sure I'm not replacing new parts when I try to move up from 180 to 220.

I'll tell you this much adding just a supercharger and intercooler with no big boost kit to my 91 and taking it from 90ish WHP to (from what I've found haven't dynoed it) 130 140 HP made my car feel like it had rocket strapped to the trunk.

[Rob®]

adding just a supercharger and intercooler with no big boost kit to my 91 and taking it from 90ish WHP to 140 HP made my car feel like it had rocket strapped to the trunk.

Then don't ever drive or get a ride in a Miata with 200+rwhp. Your 140 will feel practically stock. If you want to stay happy with your power level, don't EVER drive the same car with more power.

It's like when I had my 300zx: When it was NA it felt pretty quick. But no matter how many mods I did to it (short of NOS), once I drove a stock twin turbo, my car felt so incredibly slow, and was a disappointment to drive (from a power standpoint). Luckily I changed all that :)

[MoonieGT]

A friend has a '91 chasis with a lightly built 99 engine with a GT28R (I think that's what it is) that puts out about 230-240 to the wheels. It's fast and very drivable on the street. It's been running a bit hot at the track the last two times out. I keep telling him to just turn the boost down, but he laughs and says it's an addiction and he can't!

[Rob®]

Sounds like he has the boost pretty low already...That's stock 1.6l motor with that turbo (and the right parts) territory. What's he running, like 12psi? Tell him to turn the wick up a bit, especially with a "lightly built" '99 motor. Well, not till he sorts out the cooling issue of course.

But no, once you get boost then realize you can get more boost, there is no going back. That's why you can't ever drive/ride in the same car with more power - you'll want it. Then you'll get it and find out what you can do differently to get even more power. Then Borg Warner announces a completely new turbo design that is supposed to be FAAAAR more efficient than what's currently on the market, so you have to decide if you want to wait till the proposed late December ship date and redo everything you just did, or live with what you just spent 5+ months making, hoping you'll be happy with it.