I'll probably never own one of these fantastic cars.....but I would absolutely love to have one, especially this one with a C5R based engine! But after reading the article in the May issue about Larry Christensen's 600HP ZL1, I am wondering why GMMG chose NOT to modify some of the driveline components which, as far as I know, are prone to failure especially with a 600HP engine. Specifically, in looking at the Spec Sheet it appears GMMG used the stock clutch (but a different flywheel), the stock driveshaft, and the stock rear end (but with 4:10 gears). I would think these components would be too weak for such a powerfull machine.....any thoughts on this?
Posted by Doug 97SS #1499 (Member # 100) on :
I believe the stock clutch is the ZO6 Stock clutch. But look at it from the engine builders perspective. That motor costs what? 30-40 grand? So it was probably thought to keep some of the base driveline components so they would break first. Thats how I look at it.
Posted by Bill Mason (Member # 1807) on :
Another limiting factor is the tires. I would think that as long as normal sized street tires are used, the driveline should survive. Lack of tire longetivity would be an issue though.
If drag radials or some other form of slicks are used......then driveline breakage would be a BIG issue IMHO.
Posted by WD,30th SS#727 (Member # 107) on :
According to Matt Murphy who builds these cars, it was not necessary to modify any further componants of the drivetrain. They beat on a prototype very hard and the stock train held up well.
Posted by 02ZL1_97SS (Member # 2100) on :
I have asked Matt to answer the questions above in this thread. Hopefully in the next day or two he will have time to address them for you.
Here are a couple of questions I will try to address for you.
quote:That motor costs what? 30-40 grand?
Fortunately is was not a $30 or $40 grand option however, it was still expensive (that's why I don't have it in my car). The C5-R 600 H.P. option was an additional $23,995 on top of the base price of the car.
quote:Another limiting factor is the tires. I would think that as long as normal sized street tires are used, the driveline should survive. Lack of tire longetivity would be an issue though.
Good point. Even with the Phase II (475 H.P.) package, I have trouble getting traction down to the ground with the stock tires (P275/40ZR18 Goodyear SuperCar F1's)
quote:They beat on a prototype very hard and the stock train held up well.
Yes........each car was throughly tested before it left Marietta, GA. If anything was going to break, I'm sure Matt wanted it to happen there before it was delivered to the owner. I believe they call that "quality control".
Just my .02 worth.
[ 22. February 2004, 07:20 PM: Message edited by: 02ZL1_97SS ]
Posted by Matt Murphy (Member # 2220) on :
Dave,
Good questions here, but let me explain why we did what we did. The base 400HP ZL1 cars (actually 430HP, but the Z06 at 405HP had something to do with what we could rate the HP at, a GM thing . . .) came with a stock Z06 clutch and flywheel (this setup was stock on LS1 Z28 and SS's by 2002). GM said it would hold up to the power, and it has very well. The light weight flywheel was something we did to enhance the high reving capability of the Z06 motors. When the 427's became an option, we talked with the guys at GM's Perf. Division and they were the ones that recommended that we stick with the stock rear end, drive shaft, and clutch. Also, I did not want to add 12 bolts, drive shafts and clutches to cars that would never see the drag strip abuse. It could have also added almost $4000 to the cost of the cars that were already in the $80K and $90K range.
Now, if you look at Larrys car as an example, GM was right on with their predictions. Larry has made over 50 passes down the 1/4 mile track with ET Street drag tires and 16" rims. The stock clutch, rear end, and drive shaft are holding up to his 11's and 1.60 60' passes. No one here or at GM will say that those pieces will last forever, but for the few guys that want to take their ZL1's (or other GMMG cars) to the track to run it hard a few times, or 50 times in Larrys case, should expect their cars to stay together.
We do test the cars before they leave, but in no way do we run the crap out of them, that is for the prototypes, and our own personal cars. Yes, each car is test driven for leaks and obvious problems or issues. If a customer asks us to test their car at the track for them and get a good time slip for them we will and we have. Keep an eye out for an article on ZL1 # 21, it recently ran a 10.94 at 120 mph and ripped a 1.46 60' time and lifted the front wheels 4" in the air. That car was a converted 6-speed to an automatic, but was running through the full exhaust with the cut-out open and ET Street drag slicks as well. That customer wanted us to add a 12 bolt, it ran with a stock drive shaft, and he drives the car around FL. It also was just over $100K when it was done.
By the way . . . Keep an eye out for our last Camaro project that we are about to announce with Berger Chevy . . .
Posted by SS_CarGuy (Member # 2065) on :
Matt.......my thanks to you for your insight and explanations as well as everyone else for their thoughts and comments. I appreciate it. Like I said, the GMMG cars are awesome and I can hardly wait for the new announcement Matt!
Posted by 2002Z4CSS (Member # 1393) on :
I can't wait to see the next GMMG Camaro project from Berger Chevrolet. Posted by NATESS (Member # 982) on :
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If anything was going to break, I'm sure Matt wanted it to happen there before it was delivered to the owner. I believe they call that "quality control". ![[Roll Eyes]](rolleyes.gif)
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