High speed death wobble
 

Hi all, I have a 2008 z06 with almost 40,000 miles. Sometimes when I drive it hard at the track or the street I get what feels like slick walk/death wobble. The car literally shifts from left side to right side and raises the left and lowers the right and changes very quickly. The longer I stay in it the worse it gets. I've had it where the car was right about to come out. This usually happens right after I upshift into 3rd or 4th gear. It gets so bad that active handling comes on and ive felt ABS engaging. The car has somewhat new Michelin super sports on it, and polyurethane motor and transmission/differential mounts. I've heard people saying it could be shocks, I have yet to do an alignment from the previous owner, so that's one thing I would try, but it happens only when I'm wide open up shifting to around 3rd or 4th gear. It's happened when I was going through the traps and it was so bad I had to get out of it. I have checked the tire pressure before and used a mechanical pressure gauge to verify. It happens only once a while, but I have a half mile run way event coming up and I don't want go to it with my car in this condition

Without any knowledge of your issue...I would put a new set of shocks (Aftermarket DRM Bilsteins) on your car. Just because!!!! I would also confirm your alignment, tire condition and balance. Wheels should be inspected also..............

I'm guessing Tires and Shocks.............. That's what I would do!

I have had my wheels checked and balanced twice, I think I will try shocks and see if that helps

Does it do it in all the traction control modes?

1.Active handling full on with traction control on(This is the default mode when you start the car)
2. in competition mode
3. With Active handling full on but traction control off(this is how ranger recommends you operate the C6Z for 1/4 mile runs.)
4. with All systems off-- traction control off and active handling off- that is when you push the traction control button and hold it for 5 or 10 seconds it shuts everything off.


You might try it with all systems off, it could be something funky going on by design with the active handling/traction control.

Check this link out- Scroll about 1/2 to 2/3rds way down and you will see ranger's detailed write up.

https://www.corvetteforum.com/forums...-settings.html

:lurk:

Alignment. Check rear sway bar for being loose, it does that. Check axle nuts for being loose.

That can happen!!

:iagree:

I had this exact same issue with my base c6 and actually ended up selling it with the issue and let the other guy know about it and deal with it.
the only similarity is that we both have Michelin super sports on the car. might be a tire issue??
I checked alignment and changed shocks with no fix.

I can understand AH engaging if the car is swerving since it will try and keep the car straight. However, ABS can only engage when the brakes are applied. You may have felt AH activating since it can apply a single brake to control car yaw.

When a car starts swerving like that it is usually an indication of a suspension problem not a wheel balance problem. Wheel alignment, tie rods, steering rack, control arm bushings or wheel hubs are chief suspects. When you get the wheel alignment checked make sure all of those other things are checked first as all but the steering rack can affect the alignment after you drive away from the shop.

Bill

Drm Bilsteins and new rubber will eliminate that for good :yesnod:

My car (09 Z) does the same thing once you hit about 125 MPH .....oddly enough, it only does it when I'm at WOT. if I slowly get up to speed it does not do it... I had all suspension components checked, alignment done and I get the same thing. I'm running Michelin PSS's and have played with the air pressure with negative results. I would had to waste the money on new shocks just to get the same results..... I was told be one tech that I didn't have enough downforce and the tires might actually be breaking loose a little making it get squirrelly. I don't believe this because when I let off the throttle it's still all over the place until I get below about 120....hopefully you get yours figured out and pass on the fix !!!!

In about a week I'll have as set of DRM bilsteins for sale. $350. Best shock upgrade out there without dropping $1000+

See this problem is not constant. It can happen sometimes at 120 and sometimes at 140 and other times be straight as an arrow. I've had the car to 190 and it was very stable (relatively speaking) that other times it was not a problem. I am pretty determined to find and fix the problem very soon. I've started trouble shooting, I've had it with AH/TC from full on to full off before. No difference. One thing that has helped is to make sure the all the tires are the same exact pressure. It has helped but not fixed the problem.

Start with the basics, check the alignment. Then look elsewhere. The wheels need to be pointed in the right direction if you expect the car to go that way too.

:iagree:

Mine with 40K miles is stable also at 180+ with stock LS7. The only non-OEM suspension parts are 275/325 Pilot SuperSports and Bilstein Sports, with alignment checked and fine. Bushings etc. all have 40K miles on them.

With the shocks and PSS it will chirp the tires on a 7K rpm 1-2 shift and hook up hard on 7K 2-3, 3-4 and 4-5 shifts. The Bilsteins also improve the ride and deal with road bumps much better than OEM shocks. They were my first mod. If you are going to do performance driving, get the DRM Bilsteins. Even if that is not to cause of your problem (I'd expect some suspension wear or alignment problem or the loose axle nuts/sway bar mounts) the shocks are an improvement you will enjoy.

Exsperienced same thing. Turned out to be nothing more than low air pressure in rear tires. Would let rear tire pressure down to about 25-26 psig to improve 60ft. times and launch at drags and and got same symtom you described. Tires are mpss. 28 psig cold seems to be as low as these tires like to be run at.

control arm bushings or alignment, assuming the tires are good and properly inflated.

If possible borrow wheels and tires from someone and see what the car does. Sometimes tires can do funny things. It could be just one tire.

Shocks will not cause this problem. Nine out of 10 times this is an alignment problem. Usually rear toe, either out or in. Some guys take it to the local Joe Blow alignment place and after that when it's still bad figure it has to be something else. Go to a reliable frame shop where they know what they're doing and will ck the entire suspension system for anything that may be worn out and causing you issues. Corvette alignment is a 4 wheel issue and needs to be done by a qualified pro with the right equipment. Make sure your tires are all the same model and are inflated to 30 PSI cold as recommended by Chevrolet.

Good luck!!

:iagree: I have chased this exact problem. I should have listened to the 4th post down in my thread. It ended up being the tires. Borrow some and change them out to eliminate them as the possible cause. If it doesn't fix the issue continue down the bushing, damper or whatever cause assessment. It would have saved me an incredible amount of time and the first time it happened I could have borrowed another set of wheels and tires from someone right there at the track and the problem would have been solved.

I have definitely had this problem, I will up the pressure a few pounds as I'm running a bit low and see it if goes away. Scared the hell out of me for sure lol.