kenw

While doing HPDE's for the last 5 years, all my instructors and almost everyone I have talked to say FI either Turbo's or Superchargers do not work well on the track. Most say that heat is almost an insurmountable problem. Many say the power produced this way is not good for the control of the car.

I have a 06/A6 APS twin turbo Vette that I am putting back to stock and selling. The heat was hard to control and by the last parts of most sessions I would need to back off or pit early. The control was not an issue, at least at my level of experience.

So many told me my car was a "time bomb" that I felt I should make a change. I should have bought a Z06 in 06 but did not know then I would fall in love with driving on the track.

Oh well, I am rectifing the problem, just purchase a 09 Cyber/Grey Z06.

So why did GM go with FI on the ZR1 given these issues??

What say you????????????????

AlwaysInBoost

Out of the people who say its impossible, I'm curious how many have actually tried to track an FI car on a regular basis compared to how many are just recycling what they heard someone say at one point in time.

I look at it like this, there are lots of OE FI cars that get tracked (VW, Mitsu, BWM, Subies, Audi's, Sabb, Porsches, ect) without issue, why is a vette any different. Not saying its simple and anyone can do it, but I do know for a fact that with the right parts combo and some forward thinking its very doable... not to mention a **** ton of fun!

VetteDrmr

I know that several of us (me included) watched with great interest when the first ZR1s got some track experience. IIRC David Farmer got to check one out, and was pleasantly surprised at how the temps stayed under control. So it seems GM did their homework.

But, as your experience shows, virtually all aftermarket FI installations have a very difficult time shedding heat. While this may be stating the obvious, it seems to me that the engine has to be designed (not just modded internally) with FI in mind to keep the btu gremlins in check.

Have a good one, and enjoy your new Z06!
Mike

AU N EGL

Why FI in the ZR1? to get the HP level up to the Super Cars the European Customers want.

But the ZR1 temps are not really that bad. Think the engineers said they went though several Heat exchanger sizes, which is normal development anyway, to get the right size. An extractor hood would / should work well too.

David and I drive some of the first ZR1s at VIR and Road America a few years ago. But then again, they were not OUR cars. these were CTF ( Capture Test Fleet ) Chevy Executive cars, the engineers brought to VIR and Road America.

So driving the ZR1 as hard as we could was not an option. I spent more time watching oil pressure, which also was not a problem.

johninar

I think it was the best method to get to that HP level, and still have a very drivable car. There is a FI '03 Z06 that runs in GT1 at Hallett and heat is just killing him. Of course there are so many ways to get to those HP levels, everyone's mileage will vary.

I'd love to drive a ZR1, if anyone has any loaners.

TheKomoman

Absolutely agree on it being the easiest, most cost efficient way to get to the HP targets they had. I'd also suggest that GM knows that the VAST majority of ZR1's built will never see the track so street setup & tuning was their primary objective. Most track oriented guys will end up in a Z06.

waddisme

I have seen couple of ZRs at Rd Atl and even in that heat they did not display any heat soak effects. I tried to run my Z for a couple of years with a procharger on it. It was fun, but the maintenance was just too much, plus it eventually melted the #5 and #7 pistons. I never had oil/coolant temp issues with mine. New motor is 100rwhp less but is faster at the track. SC hp and torque doesn't really kick in until higher rpms. There are still a couple of diehards who do, if you go to FI section. Streetwise, the SC is more user friendly, but not at the track.

96CollectorSport

When most folks talk about FI for the track they are just looking at installing a blower on a stock LS6/LS2/LS3. Since those are all higher compression engines the heat is going to get you. Now if you start from scratch the way GM did with the ZR1, lower the compression and build a forged bottom end you will be able to get it to work. If you have to build the bottom end then you may as well build it to 427+ci make around 600 hp and call it a day.
IMO the cost is why FI isn't seen more at the track. For raw numbers figure $30k to go FI in your track car. $15k for a forged motor, $15k for the FI kit and install. Most of the time you can do a NA engine for about 1/2 of what it will cost to do FI.

BrianCunningham

FI has been used for years on track cars

it just needs to be properly engineered

GM did their homework

Buckeyefaninks

Great question... I think it basically boils how much money you have to throw at the problem. I have an FI '02 Z06 which was always perfect on the street in any weather, and on the track if the temps were below 80. I did all I could, within my budget to solve the heat problems on hotter days. Louvered hood, Dewitts radiator / spall fans, straight distilled water and Water Wetter instead of coolant, minor ducting to force air threw the radiator, always short shifting, etc. I couldn't make it work.

If I had the resources of GM, I'm sure I could have made it work. I bet the ZR1 is as solid temp wise as the Z06 due to their ability to test, and test, and test.

Money, time, and resources...

varkwso

I have yet to see a ZR1 driven really hard (Jason, Mark, Scott or Jake hard) at a track event. They seem to handle DE with no real issues but they are not real common on track. But GM did boost it to hit their marketing HP numbers and engineering did their job making it work.

AU N EGL

and the Corvette engineers who designed the ZR1 and GS came though the NCM or other driving schools. Asked lots of question, and spent track time driving too.

trapp

I have a 09 C6 Z51 with procharger at 6psi. I run 20-30 sessions without any issues with heat. I of course upgraded to a LG supercooler and a separate upgraded oil cooler and I have no problems with heat. I do believe turbochargers are bigger producers of heat as compared to superchargers...

tjZ06

GM built the ZR1 as a "halo car" and a magazine darling, not to be a track day car. I still swear GM needs to build a car a-la 911 GT3, Viper ACR(X) etc. I really hoped the Z06 Carbon was going to be that car, but it really turned out to be a perv-o, waxer/collector car.

A C6Z06 w/ some minor weight reduction (non-reclining carbon race seats for one), brakes (probably best just the iron-rotor setup from the C6Z w/ one-piece track pads instead of the pad-lets, but ideally a StopTech/AP/Brembo/etc sourced setup), aggressive alignment (the C6Z alignment is biased towards tire wear for waxers, and with the allowable tolerances it's possible to have positive camber from the factory!!!!!), and Cup Sports and true aero would make it a world-beater.

The Z06 already holds up pretty well against the "factory track cars" but with just those minor changes it would tear it up.

-TJ

jvp

Were that the case, they wouldn't have bothered doing all the cooling work they did with the Eaton. Nor would they have bothered spending all that time and money at the 'Ring with it, either. It is a better GT than the Z06, but it's also a better track car. In every, single, possible manner.

Swear all you like, GM won't do it. The number of people that'll buy that version of the Corvette is very small, and GM knows that. Their research has told them people don't want a stripper Corvette. You might buy one. A few others here on the forum might buy one. Most people won't.

jas

varkwso

Hill climbs - OK

OLOA - OK

AutoX - do not know how they fair

Mile races - made for it....


Competitive track events - personally, have not seen it yet. SCCA or NASA.

AU N EGL

But then look at all the T1 cars and ST2 C5s, stripped out then race prepped.

There are 2 ZR1s race prepped that I know of. Both wrapped like C6Rs, One up in NY ( crashed video on WG )last year.

One in FL.

Both run NASA SU but are really not that fast. Could be driver skill or just not wanted to crash a $180K race car.

You are right we have had that discussion with Corvette Engineers. and the Grand Sport was born.

The question we get is why are not more C6 Z06s Raced ? Cost to convert, especially putting in the roll cage on the aluminum frame. Too expensive for the average racer.

Those that are converted are really C5s with ACP Carbon Body aka Speed World Challenge race prep.

As used C6 prices come down, we may see more C6s stripped and prepped for NASA ST2. ALso providing some of the nannies can be tuned out and a Mechanical door lock and latch attached.

There are several in C6s SCCA T1 and a few C6Zs in SCCA SPO. IIRC most of the SPO corvettes are Speed World Challenge prep, aka old C5 frame with ACP Carbon C6Z body

tjZ06

I will absolutely argue that a C6Z is a better track-day car than a ZR1, but it's always just going to be my $0.02 against yours.

I can say that last summer at THill it was 105-110 F ambient outside. There was a ZR1 driven by a very skilled driver with literally hundreds of sessions at THill vs. my 4th session there (he's gone 1:3x in his open-wheel car at THill). We ended up in the same group for a session. I followed him for a few laps, and was able to stay right with him in my C5Z with about 420 RWHP out of a 348. On the long straight at THill I was pulling dead-even with him. He couldn't walk me, and I couldn't gain on him. He finally gave me the wave-by and I very, very slowly put space on him before we got into traffic.

He said he was wooded on the straights. Heat-soak had to be costing him over 100RWHP since ZR1s are known to dyno ~550ish stock and my car had literally put down 420 (I think it was 422) a few days prior (I had it in for new valve springs and check-up on the tune).

I was also on stock '02 Z06 springs, stock '04 Z06 shocks, GM T1 front sway, stock rear sway, semi-aggressive alignment and 710s. Yes I know I was on better tires, but they were the "small" setup (275/315) and were over 5 years old and pretty heat cycled out.

I haven't found well-driven C6Zs as easy to hang with.

A stock ZR1 is probably faster than a stock C6Z06 around just about any road course if it's bellow 80 F ambient. But most of that is honestly just from the better stock tires. The stock C6Z06 tires are a disgrace to the car.

But I say the C6Z is the better track day car because you can get them for 40-50k less (assuming you are buying both brand new, at real world going prices right now). With the minor tweaks I described before (tires/brakes/alignment primarily) it's going to run with or past a ZR1 and still be much less $ and less of an issue on hotter days.

Hey, I never said GM would do it. Of course they won't... because it's the right thing to do!

Are you honestly going to argue on the side of GM's market research and ability to run a profitable business? They have without a doubt proven their ineptitude at understanding the market and running a profitable business. You do know Porsche is the most profitable automotive manufacturer, right? Heaven forbid GM take a hint from them. You go ahead and back your argument with GM's research and decision making... you're simply making mine for me!!!!

-TJ

jvp

The thing is, I have DIRECT experience driving my C6 Z06 at the track and can put that against my DIRECT experience driving my ZR1 at the track. You can't do that, can you?

The ZR1, from the factory, is a better track car than the Z06 is, from the factory. Period. This is proven by the track times that the ZR1 continually posts which are faster than the Z06's are. The power is there, the torque is there, the grip is there, and the suspension and brakes are all there.

The Z06 is a fantastic car, no question. But the ZR1 is better. The added cost of the car does, in fact, buy you more.

There's no "probably" about it, and the ambient temperatures aren't going to matter. GM did their research with the car's coolers and it shows at the track.

Here we go. Any "minor tweaks" you can do to a Z06, I can do to a ZR1 and I'll still beat ya around the track. Yes, the Z06 is going to be less expensive, and the used ones even more so. But that's not the point of this thread, is it?

Really, it isn't. GM knows its Corvette buyers better than you do. Trust me on that. They have over 50 years of experience to back it up. Stripper Corvettes will not sell in volume to make it worth their time and effort. Yep, they'll sell a few of them. But it won't be a high enough number to matter.

You are SO far out in the weeds here it's almost comical. Corvette is still one of GM's most profitable lines, even during the economical disaster we're going through. Yes, they're selling fewer of them now than they were before. Know why? Because folks are a little tight on money, that's why. It has nothing to do with GM's "marketing" of the car.

Now then, back on topic, shall we?

jas

tjZ06

If GM is so great at reading the market for Corvettes and building the proper car, why are there still 500+ brand new '10 ZR1s on the lots with over $12k off MSRP and 0% being offered (or $15k off if you don't finance)?

Both the Z06 and ZR1 are amazing cars. Agreed.

The ZR1 is faster. Agreed.

None of this means there's not a market for a niche-player car along the lines of the ACR or GT3. The Z06 Carbon is cool, and I think collectors and waxers will love them, but it's not the track day car a lot of us want.

Maybe all GM needs to do is offer a "Track Pack" for the Z06 rather than introduce an entirely different model.

And you didn't address the issue of the ZR1 that I pulled dead even with on 420 RWHP in 110 F ambient temps. The owner himself said the car was much better in the cooler morning temps, and it was clear in the heat of the day it was way down on power.

Anyway, don't get me wrong I love ZR1s. And to get back on topic and address the original question of why GM chose FI for the ZR1 when FI is known to be problematic on the track I will reiterate my original argument: GM was building a "Halo" car. There is no way the could have achieved their power goals in a smogable, warrantied package NA so they went FI. Yes, they put lots and lots of R&D into the cooling to make it work on the track. But the track was not their primary design concern.

-TJ