I have an 03 Z06 with 4,000 miles. I'm disappointed with its performance. I can reach 137 mph before it starts cutting out like a fuel starvation problem. Also, the valve train is just hammering away. It's so loud over 4,500 rpms that you can't hear yourself think. I've run several brands of 91 octane gas with no difference in performance. It also backfires frequently after letting off the gas. The dealer has checked all configurations on the computer and says there is nothing wrong with the car. The service manager, Mr. Corvette, to others at the dealer says my expectations are too high. I know there's something wrong when this vette can't outrun a Mustang GT or a Honda S2000 both of which cleaned my clock. Please don't tell me to learn to get away from the line fast. My 96 C4, fully stock, will outperform this Z06. :confused: Any suggestions would be appreciated.

 

get in touch with RG at exit 28 motorsports..he'll know what do to. I would NOT put up with that kind of service. :mad

When you pay 50k for a car like this , it better be dead on PERFECT!

There's a few members pulling 11 second timeslips with a STOCK CAR so the Z is all that. I just took mine to the track this past Tuesday night with a little over 350 miles on the motor and she screamed like a raped ape..absolutely no problems. glad i did now

keep us informed

David In Indy
03Z-Ripper




[Modified by ledfoot, 6:06 PM 5/9/2003]

 

Thanks! I'll post future R.&R. events until the car runs right. :steering:

 

Well, you have a lot of information above, lets break it down shall we............


1) I can reach 137 mph before it starts cutting out like a fuel starvation problem.

*** (corrected) this can happen if you are reaching the rev limiter at 6600rpms, which you shouldn't be at 137mph. Now I'm suspecting a possible clogged fuel filter, bad/clogged injector, fuel pump, spark plug, etc, etc. Could be a number of things.

2) Also, the valve train is just hammering away. It's so loud over 4,500 rpms that you can't hear yourself think. I've run several brands of 91 octane gas with no difference in performance.

*** the valvetrain is loud, but at 4500rpm all you should hear is the exhaust note. Gas won't affect the valvetrain noise or the exhaust noise.

3) It also backfires frequently after letting off the gas.

*** the popping is normal for a high-comp engine and the H-pipe. If it sounds like like 1 big boom or like a gunshot, then that's not normal.

4) The dealer has checked all configurations on the computer and says there is nothing wrong with the car. The service manager, Mr. Corvette, to others at the dealer says my expectations are too high.

If he just checked for trouble codes, that doesn't catch everything. Z06 owners should have high expectations. You should be able to lay rubber in 1st, 2nd and 3rd gear accelerations, shifting at around 6,000rpm

5) I know there's something wrong when this vette can't outrun a Mustang GT or a Honda S2000 both of which cleaned my clock. Please don't tell me to learn to get away from the line fast. My 96 C4, fully stock, will outperform this Z06.

*** A Z06 will be able to out accelerate a stock GT, S2000 or C4 off the line, 0-60 and quarter. You either have an engine problem, driver problem or the cars you raced weren't stock.


Here's what I would do if it were my car:

1) Get it dyno'd. Your '03 should be able to put down at least 345+rwhp SAE corrected.

2) Find another Z06 owner in your area and compare cars. Swapping cars if necessary. Both of you going to a dragstrip and drive each other's cars would also be a good comparison.




[Modified by TexasRedZ06, 9:32 AM 5/11/2003]

 

Nope, I have run 140 mph at roebling road in 4th around 6000 rpm.

What do you mean valve train noise, ticking? I would guess either something is wrong or you don't know how to drive.

 

Take in a recent copy of any car magazine to show "Mr. Corvette" at the dealer. Show him the stock Z06 times as opposed to the Mustang GT and Honda S2000. Explain to him that you are not expecting too much from your car. They don't use the Z06 in high speed shootouts with Lamborghinis and Vipers just to turn around and get beat by Mustangs on the street.

I agree that something is definitely wrong. But take it to someone that knows Corvettes. Dealers are clueless. :cuss

 

Damaged valve springs or sticking valves can cause backfiring--- and the valve-train noise you heard???

Dan

 

Recently I had low rpm sputtering noise like a miss, thought I had a leaking head gasket or something, pulled the covers and found a broken valve spring, you may want to look under the valve covers.

 

I'd spend a few bucks and have your car dyno tested, with a air/fuel measurement made. It will show up right away if the car is running lean, or if the power is low compared to other cars, or if there is some other mechanical problem affecting performance.

Unless you are just spinning your tires, a S2000 or Mustang GT should be NO sweat for even a regular C5 Corvette, let alone a Z06!

Something is definitely wrong. :smash:

 

Other than for my small correction above, :iagree:

There is no way ANY S2000 should walk you without grenading his engine. The valve train noise and popping is normal in a Z06. Mine pulls strongly to 142 mph in 4th and nicely again to 160 mph in 5th... I would have my car checked...

:cheers:

 

I'm going to have it dyno'd next week. I'll post the results as well as what the tuner recommends. Thanks. :seeya By the way, when the engine crapped at 137 mph, the tach was at 4500 rpm's and wouldn't rise above that in 5th. :cry

The first 3 gears walked right up to redline and the speed limiter without any problem. :D


Some buddies and I ran 0-60 times, each taking turns driving and then averaged the times. They were 5.5 seconds, 5.9 seconds, 5.5 seconds and me at 5.7 seconds averaging around 5.7 seconds. None of us are skilled drag racers so, maybe someone who is, could run a little faster in this car, especially without the added weight of another person on board leaning on the driver to watch the speedometer. :steering:

 

Even if your a bad driver who weighs 300lbs and your friend is 300lbs you should be able to do a lot better than 0-60 in 5.7 seconds in a z06!

That is unless you take a break to look around between your shifts and eat a hamburger or something.

:steering:

 

So you can't get above the mid-4000s in 4th or 5th gear??

It could be a broken spring like others have said above. However, I'm not sure why you are having the problem in the higher gears only. It could be something as simple as a clogged air filter, clogged fuel filter, bad fuel, bad/clogged injector, bad fuel pump, fouled spark plug, etc. It does require more power to push the car at higher speeds. Have you checked for any error codes??? The dyno should tell if you have problems, but it can't simulate the air resistance.


[Modified by TexasRedZ06, 9:45 AM 5/11/2003]

 

Now that's a problem for sure. This has nothing to do with driving ability or having a dud. But it will be fixable.

 

that would depend greatly on how sticky the road is.
takes a lot of skill and a good road to dip into the 4s

 

91 Octane is the highest you can get in Arizona? Whats your elevation? Maybe thats irrelevent but I'm curious.





[Modified by BRADS C5, 10:31 PM 5/12/2003]

 

I'd say a dyno would be the best way to go. Better yet, see if whoever has the dyno has a copy of LS1Edit as well if you have done any mods. After putting on intake, headers, exhaust, my Z06 was running AF around 9!!! It was so rich that I about gagged on the smell. Put it on the dyno and saw it running 325. After bumping the AF to 13 it is running much happier at 378.

-Alex

 

Sorry for not getting back with you earlier. Altitude is around 2,800ft. here.
How about adding racing fuel? It's available in unleaded at around 110 octane. Maybe adding about 5 gallons to an empty tank, then filling the rest of the tank with 91 octane. See any problems looming with that fix? :auto:

 

Don't use leaded fuel like 110 in the Vette. You'll kill your 02 sensors. If you need octane get 1 gallon of Toluene or Xylene to add to 5 gallons of gasoline. or buy 104 octane unleaded racing fuel.

 

If I use 104 unleaded racing fuel, which I can buy here, do I use a 50/50 mix or something different? Have you used it in your Z06 or know anyone who has?