Use of forced induction for GT cars (or lack thereof)

[trahsub]

BMWs move to forced induction for their M cars got me thinking about how the vast majority of 'super cars' continue to use normally aspirated engines. Porsche is a good example of offering a variety of powerplants in the 911 Turbo and 911 GTx models, with the GT3 being the homologation model. It's rare though to have such a wide variety of engine choices in the way Porsche offers things.

So the thought is, with BMW moving to turbo, and one-engine offerings for cars like the GT-R, will the equivalency formulas between NA cars and FI cars need to be adjusted so the performance is within the ball park for each type of power plant?

Hopefully BMWs love of FI doesn't keep the iconic M3 out of LeMans racing for a long time...although we know they are focused on DTM in the near future.

[Fogelhund]

Originally Posted by trahsub

So the thought is, with BMW moving to turbo, and one-engine offerings for cars like the GT-R, will the equivalency formulas between NA cars and FI cars need to be adjusted so the performance is within the ball park for each type of power plant?

It would indeed need to be adjusted to attract back Turbo engines. In addition, I think they need to increase the allowable displacement again.

[Accident]

Originally Posted by Fogelhund

It would indeed need to be adjusted to attract back Turbo engines. In addition, I think they need to increase the allowable displacement again.

Very much agreed. I'd like to see the cars allowed to use engines that follow their road car philosophy. Bigger torquey V8 for Corvette, larger V12 for the Aston, potentially a big V10 for the Viper (if the program ever comes around and if it follows previous model trends).

One of the things I love about the GT class is seeing different ways to solve the same problem, and I feel that the lower displacement cap kinda takes away from the variety of "solutions."

[Mt. Lynx]

I would like to see a rule forcing constructors to use the same engine configuration as the roadcar they take the chassis from. IE a SC V8 for Vette ZR1, a TT V6 for Nissan GT-R, NA V10 for Audi R8 etc. Just put a power cap on them, like 450 kw or so.

[trahsub]

Originally Posted by Mt. Lynx

I would like to see a rule forcing constructors to use the same engine configuration as the roadcar they take the chassis from. IE a SC V8 for Vette ZR1, a TT V6 for Nissan GT-R, NA V10 for Audi R8 etc. Just put a power cap on them, like 450 kw or so.

The problem with a simple cap are the iterations involved in the power delivery through the curve. 450 peak HP is fine if all engines were for the most part the same (low displacement, all NA, etc...)but the torque curve is what makes balancing things out really tough. And this is also where turbo cars excel, peak torque at very low RPMs (which means the things will be gone when they come out of corners).

I would NOT want to be the guy determining how to balance out a SC V8, TTV6, NA V10. That is tough. Maybe the answer is getting all the cars competing on a dyno and adjusting accordingly.

[JAG]

For years you had XJ220's, 911 Turbo's, F40's, Venturie's, turbo's haven't been popular in GT2/GTE mainly due to the equivalent road cars not using them, that will change with the Mclaren, new BMW's etc.

[Graham Goodwin]

Originally Posted by JAG

For years you had XJ220's, 911 Turbo's, F40's, Venturie's, turbo's haven't been popular in GT2/GTE mainly due to the equivalent road cars not using them, that will change with the Mclaren, new BMW's etc.

Oddly enough am working on a story right now for another one!

[johntt]

GT cars being production based, follow production trends. The current trend is moving towards turbos so thats how it will go in the current years.

[I Rosputnik]

I wonder if it might be the Hyundai Genesis Coupe. The top of the range model uses a 3.8 turbocharged engine, and it would be interesting to see how it would fair. It seems strange yes, but it's not the kind of car you would see in touring cars.

[Accident]

Originally Posted by I Rosputnik

I wonder if it might be the Hyundai Genesis Coupe. The top of the range model uses a 3.8 turbocharged engine, and it would be interesting to see how it would fair. It seems strange yes, but it's not the kind of car you would see in touring cars.

I hope not, I don't really want to see another sports coupe morphed into a GT car like the M3 was.

[alexkiller8]

for endurance races i don't know how much good is to have a turbo engine, too much risks about reliability, engines too much complex and expensive to develope, turbo lag etc.... i think that a turbo engine is usefull only in competitions where is required to obtain enormous power output, in this way can be used a not so large displaced turbo engine aiming for a costs reduction, but also in this option i don't completly agree with my same opinion.... after all it's not a coincidence if nissan in GT500 switched to the NA VK45 in super gt after disappointing feedbacks from the v6 turbo.

[Mt. Lynx]

Originally Posted by alexkiller8

for endurance races i don't know how much good is to have a turbo engine, too much risks about reliability, engines too much complex and expensive to develope, turbo lag etc.... i think that a turbo engine is usefull only in competitions where is required to obtain enormous power output, in this way can be used a not so large displaced turbo engine aiming for a costs reduction, but also in this option i don't completly agree with my same opinion.... after all it's not a coincidence if nissan in GT500 switched to the NA VK45 in super gt after disappointing feedbacks from the v6 turbo.

Lots of LMP´s use turbos. And as for SGT; they are forced to use a V8, that is why they do that (this is also the reason I think we´ll never see the LF-A in SGT). GT1 on the other hand, they went for the block from the Titan, instead of using the V6. But doesn´t the GT3 GT-R run the V6?

[alexkiller8]

Originally Posted by Mt. Lynx

Lots of LMP´s use turbos. And as for SGT; they are forced to use a V8, that is why they do that (this is also the reason I think we´ll never see the LF-A in SGT). GT1 on the other hand, they went for the block from the Titan, instead of using the V6. But doesn´t the GT3 GT-R run the V6?

well, the only turbo used in LMP are the not so updated AER and AER-mazda and from this year the 2.8 honda of lmp2, but just because for new regulamention matters honda doesn't produce a large displacement road NA engine, so was forced to use that. About sgt500 nissan and toyota switched for larger NA engines years before the actual mandatory formula nippon derivated 3.4 v8.
About GT-R, nissan used in GT1 the 5.6 v8 because the car needed the most powerfull road derivated engine possible, that engine (built only in USA) is a typical low revlimit american v8! the GT3 GT-R uses the v6tt because rules in gt3 about engines are more restrictives, but nothing will deny nissan to swap for another nissan producted engine (as happens for the z4 gt3 that uses the 4.4 v8 of the m3 gts or ford GT3 matech that now uses a 5.0 roush and not the supercharged engine of the street ford GT)

[WolfsburgRS]

Originally Posted by alexkiller8

for endurance races i don't know how much good is to have a turbo engine, too much risks about reliability, engines too much complex and expensive to develope, turbo lag etc.... i think that a turbo engine is usefull only in competitions where is required to obtain enormous power output, in this way can be used a not so large displaced turbo engine aiming for a costs reduction, but also in this option i don't completly agree with my same opinion.... after all it's not a coincidence if nissan in GT500 switched to the NA VK45 in super gt after disappointing feedbacks from the v6 turbo.

Quite the contrary, turbo motors have proved themselves plenty reliable for many years - just look at nearly every overall winner at Le Mans going back 30+ years. There are a few notable exceptions (Jaguar in the 80s) but the vast majority are all turbo motors. Even small 4-cylinder motors like those used by Toyota in the GTP cars in IMSA proved reliable at places like Sebring, a race not known for being easy equipment.

The only reason turbo motors are not used in the vast majority of racing applications these days, in my opinion, is that they have been legislated to the point of being non-competitive. Just opening up the regs slightly would allow a turbo motor to be more than a match for the NA motors we see these days. Sure marketing ties into it, but as far as making power easily and effectively, turbocharging is a proven technology.

Ironically it's because it's so easy to make power with a turbo motor, reliably, that they have been so restricted.

[Victor_RO]

Originally Posted by WolfsburgRS

Ironically it's because it's so easy to make power with a turbo motor, reliably, that they have been so restricted.

And it's some of those restrictions that may have hurt the capacity of turbo racing engines in LMP2 to produce power reliably; see the shambles that was the whole of 2009 in LMP2 in the LMS.

[Fogelhund]

Originally Posted by alexkiller8

well, the only turbo used in LMP are the not so updated AER and AER-mazda and from this year the 2.8 honda of lmp2, but just because for new regulamention matters honda doesn't produce a large displacement road NA engine, so was forced to use that.

Umm... well the Peugeot's and Audi's are turbo units...

Otherwise, ACO just messed up the equivalency in LMP2, so not really the turbo's fault.... yes there was an issue with turbos in 2009, but wasn't that a fuel issue.

In fact, a turbo charged car has won the last twelve LM. Strange that, if they aren't reliable.

[alexkiller8]

Originally Posted by Fogelhund

Umm... well the Peugeot's and Audi's are turbo units...

Otherwise, ACO just messed up the equivalency in LMP2, so not really the turbo's fault.... yes there was an issue with turbos in 2009, but wasn't that a fuel issue.

In fact, a turbo charged car has won the last twelve LM. Strange that, if they aren't reliable.

well we are talking about petrol engines, a turbo-diesel engine is another question. And even the turbo engines of r8-speed8 era can't be compared to the actual ones.

[Fogelhund]

Originally Posted by alexkiller8

well we are talking about petrol engines, a turbo-diesel engine is another question. And even the turbo engines of r8-speed8 era can't be compared to the actual ones.

So after decades of being reliable in petrol motors, turbos are suddenly unreliable? How is a diesel turbo a different issue?

[Tim the Grey]

Turbos are fitted to millions of vehicles worldwide, and run, happily, for years.
I have a Golf TDi, 12 years old, 240 thousand miles up, original turbo. Yes, they are just SO useless, these turbo thingies...

GT-E will run turbos, when the manufacturers want/need them to...

[alexkiller8]

i didn't say that turbo engines ARE NOT reliable, but because of their more complex nature are less reliable than the NA ones.

[Mt. Lynx]

One can argue that turbos aren´t in favor in GT´s though. IIRC the rules say that if they have a turbo, the displacement can´t exceed 4.0l, and also that they have to use the original turbos aswell, and that is the probably the cause for the non-existant turbos in GT (until GT3) since the mid-nineties. AFAIK there has only been one try with a turbo in recent years in GT1. A Porsche 911 turbo participated in a few LMS rounds a few years ago.
Could be about to change with the current downsizing trend, though.

What about the Lotus Evora GTE? What sort of engine do they run?

[Victor_RO]

Originally Posted by Mt. Lynx

What about the Lotus Evora GTE? What sort of engine do they run?

4-liter Cosworth (Toyota GR-based) V6 instead of 3.5 in the road car.

[Fogelhund]

I don't think there will be a downsizing trend in GT anytime soon. The rules simply are biased against Turbocharged engines for the ACO, and have been since about 98'.

[trahsub]

Originally Posted by Fogelhund

I don't think there will be a downsizing trend in GT anytime soon. The rules simply are biased against Turbocharged engines for the ACO, and have been since about 98'.

When a big Marque like BMW makes the switch on their halo road car, perhaps that has influence on the current rule book. I know they (BMW) seem to be moving away from LeMans for now, but if a couple of the big teams around year after year needed better rules with respect to turbo, I imagine things would change.

[Dead-Eye]

Originally Posted by Fogelhund

I don't think there will be a downsizing trend in GT anytime soon. The rules simply are biased against Turbocharged engines for the ACO, and have been since about 98'.

The rules are biased against turbos. But if you're a big manufacturer and the ACO wants you to come (or stay), rules are negotiable.