Turbo / SC Nightmares anyone?

[A.S. Motorsport]

tuning and sensibility are key in a forced induction setup.
I have how ever a nice memorabilia from a part out NSX of how to fail, a completely destroyed head, and a piston that got artistic by welding it's valves on to it.

I've heard dozens of horror stories on FI cars.
From tuning failures to engines that can't handle the power.

A few days a go I saved a WRX from complete engine failure, owner started to mess with his boost valve to the point the car was making 7 PSI over the known failure point of the engine.

It wasn't funny the car went in to knock with out even flooring it even cutting out due to lack of injected fuel. a quick boost valve adjustment fixed the problem.

But this shows on turbo cars tiny things can have huge effects that's why careful tuning and consideration are key.

 

[BobK]

Ok, I'll make this simple, regardless of which FI system you choose and assuming nothing goes wrong:

<$20,000 : 400-450 whp
<$40,000 : 500 whp
<$60,000 : 550 - 650 whp

Done. :smile:

I don't know about the 500hp and above costs but I can tell you that you are way off on the 400-450hp numbers by about double! You can easily build a 400hp car from any of the well known builders installed and tuned for $10,000. Ask me how I know!

 

[stuntman]

I don't know about the 500hp and above costs but I can tell you that you are way off on the 400-450hp numbers by about double! You can easily build a 400hp car from any of the well known builders installed and tuned for $10,000. Ask me how I know!

But will there be quality components engineered to take the abuse the power output can make? Specifically: IAT cooling and also a few other factors.

What many people forget is while a system (turbo and specifically superchargers) make a certain power# on the dyno. That is ONE pull. On a track where you're on it all the time, the IATs will continue to rise and find an equilibrium. Due to the design (or lack of cooling like many superchargers) this equilibrium usually has VERY high IATs which at best, a good tune will simply rob power and you won't have the 400whp your car dynoed at. So you'll be driving on a track with a much lower power number than you believe you have. Is a $8K-ish supercharger worth 300, 350, 360whp when you dynoed at 400 with it all nice and cool?

Worst case - this increase in IATs can cause your motor to blow up.


0.02

 

[Vega$ NSX]

I don't know about the 500hp and above costs but I can tell you that you are way off on the 400-450hp numbers by about double! You can easily build a 400hp car from any of the well known builders installed and tuned for $10,000. Ask me how I know!

Keep in mind, that is total installed price with all necessary items for a complete, out the door package. Add the price of gauges. Add the price for tuning, dyno time. Add the price for upgraded equipment. Add the price of any potential future problems, tuning etc. For the higher power number, it includes upgrade fuel systems, clutch, brakes etc. Something almost always goes wrong so if you don't have to experience that, consider yourself lucky. Also note the < symbol, so it is possible to do it less, but I tried to give the limit pricing to do it right and do it well. Finally, keep in mind, it's just a simplified chart. :smile:

Oh yeah and what Billy said. :biggrin:

 

[nsxnut]

I think Gerard here had over 75,000 miles on his CTSC motor mainly on the racetrack. There are a few more. Some really high mileage CTSC cars. An even power band, lower boost, and lower overall output is also a bit easier on the internals.

I put a CTSC on my car at 82K. Had the motor rebuilt at 120k.
I had more than 125 track days.

When I had the motor rebuilt I sold for a larger displacement blower.

Very reliable setup.

 

[Coz]

Yes, I did, sorry Brian...

...and Yes, I remember, it's your fault I'm where I'm at with my NSX, you got me started down this path...LOL...loving every minute of it, except the rebuilds of course

You NSX was the most impressive I had ever taken a ride in.

I think you have me mixed up with VegasSpeed. He's the one with the Brooklands Green CTSC NSX. I'm the guy with the Turbo Widebody you rode in before you did up your NSX. Remember, you stopped by my house.

 

[RYU]

I don't know about the 500hp and above costs but I can tell you that you are way off on the 400-450hp numbers by about double! You can easily build a 400hp car from any of the well known builders installed and tuned for $10,000. Ask me how I know!

Using Brian's simplified matrix.. this might make more sense to you :biggrin:

<$15,000 ($5k contingency) : 400-450 whp
<$30,000 ($10k contingency): 500 whp
<$45,000 ($15k contingency): 550 - 650 whp

FWIW I think if you've accepted this equation then you'll be prepared climbing the FI ladder.

+

=

 

[TURBO2GO]

I completely agree with Billy, the power you make on a few cold Dyno runs is way different than what you are making on a hot track day. Dyno runs are misleading. I've dyno'ed at a low of 318 to a high of 396 on different dynos. Yes the engine was heat soaked on the 318 run and cold on the 396 run. I guess this is one area the NA setup is superior, something none of you NA Fanboys pointed out. LOL... FI = heat.

 

[stuntman]

I completely agree with Billy, the power you make on a few cold Dyno runs is way different than what you are making on a hot track day. Dyno runs are misleading. I've dyno'ed at a low of 318 to a high of 396 on different dynos. Yes the engine was heat soaked on the 318 run and cold on the 396 run. I guess this is one area the NA setup is superior, something none of you NA Fanboys pointed out. LOL... FI = heat.

BUT a proper designed intercooler system that reaches an equilibrium low enough to not change the IATs enough to cause the tune to compensate and reduce power, will not have that problem. It's taken us years testing different cores, designs, sizes, etc... Its not as simple as buying an IC, and heat exchanger and "it will be good because it was good on the dyno". But a properly designed system negates this problem, which is a substantial problem for most SC setups (even the aftercooled ones).


0.02

 

[Mac Attack]

BUT a proper designed intercooler system that reaches an equilibrium low enough to not change the IATs enough to cause the tune to compensate and reduce power, will not have that problem. It's taken us years testing different cores, designs, sizes, etc... Its not as simple as buying an IC, and heat exchanger and "it will be good because it was good on the dyno". But a properly designed system negates this problem, which is a substantial problem for most SC setups (even the aftercooled ones).


0.02

I agree a few dyno runs may not simulate long-term track performance, but how many of these vehicles see that?

One could even argue that the low air flow rates to the engine bay and radiator on a stationary dyno may kind of offset the additional long-term wasted thermal energy from the engine that's running on a track with a 100MPH wind :wink:

If someone is tracking their forced-induction vehicle, than they should be datalogging IAT, water temp, oil temp, and even EGT to ensure their A/F ratios and timing are good.

There have been quite a few professional teams that track supercharged vehicles successfully. While I don't have direct experience with tracking a supercharged vehicle, I have turbocharged ones. As an engineer with a very strong theoretical and practical background in fluid dynamics and heat transfer, I can't imagine why supercharger intercooling would be any worse than turbo intercooling given the same intercooler I haven't researched compressor efficiencies, but maybe some turbo compressors are a lot more efficient? Otherwise, for a same brake horsepower engine with the same turbo or a supercharger centrifugal compressor, the wasted thermal combustion heat completely overwhelms any small differences between the two!

Dave

 

[stuntman]

I agree a few dyno runs may not simulate long-term track performance, but how many of these vehicles see that?

One could even argue that the low air flow rates to the engine bay and radiator on a stationary dyno may kind of offset the additional long-term wasted thermal energy from the engine that's running on a track with a 100MPH wind :wink:

If someone is tracking their forced-induction vehicle, than they should be datalogging IAT, water temp, oil temp, and even EGT to ensure their A/F ratios and timing are good.

There have been quite a few professional teams that track supercharged vehicles successfully. While I don't have direct experience with tracking a supercharged vehicle, I have turbocharged ones. As an engineer with a very strong theoretical and practical background in fluid dynamics and heat transfer, I can't imagine why supercharger intercooling would be any worse than turbo intercooling given the same intercooler I haven't researched compressor efficiencies, but maybe some turbo compressors are a lot more efficient? Otherwise, for a same brake horsepower engine with the same turbo or a supercharger centrifugal compressor, the wasted thermal combustion heat completely overwhelms any small differences between the two!

Dave

you are assuming centrifugal and not a screw type blower.

Also stagnant engine bay temps (with possible heat soak) and reduced airflow to the radiator from just a floor fan does not affect IATs much.

 

[Mac Attack]

In short what I am saying is that I am not buying this argument that "you are at 6-8K anyway" and therefore it is OK for your car to produce power in that band. The wider the power band the better. I really don't like this super high RPM only power. It sucks to be honest.

First, I did say 5-8k, as 6-8k would be a little higher than I'd like (obviously with redline at 8k).

I don't know what track you mostly run on, but maybe that track prefers your (stock?) gearing with the 6speed. There's a reason real race teams have transmissions with various gear ratios when they travel from track-to-track, and why they concentrate engine torque/power in a relatively narrow RPM range.

If you just don't like shifting, that's fine. Personally, I would take the newest automated paddle shifters any day over my manual ones for the track.

Dave

 

[Mac Attack]

you are assuming centrifugal and not a screw type blower.

Also stagnant engine bay temps (with possible heat soak) and reduced airflow to the radiator from just a floor fan does not affect IATs much.

Yup.

I agree. But for an A2W intercooler with a front mount heat exchanger, it should :wink:

Dave

 

[stuntman]

Yup.

I agree. But for an A2W intercooler with a front mount heat exchanger, it should :wink:

Dave

I don't believe it would reach the equilibrium track temp without excessive continuous dyno pulls. You could eventually get it there but it would probably require a lot of pulls which most people don't do. It all comes down to recording and simulating the same conditions -which most people don't do.