High Speed Steering Instability
Race Director
Joined: Oct 2004
Posts: 10,089
Likes: 14
Originally Posted by Turbooo2u
I've driven the base and Z51 equipped coupes for well over 1000 miles each. The base coupe (my personal car) has way more high-speed stability, even when modded with Z51 bars, aftermarket rims and tires and Z51 shocks. It's the Z51 monoleaf springs that are too stiff and introduce bump steer on all but pool table flat roads. Thats why I always get the base suspension and mod it but leave the springs alone.
The base springs are a much better match to the weight of the car. Springs that are too stiff cause the car to skitter on pavement irregularities.
Racer
Joined: May 2005
Posts: 257
Likes: 0
Originally Posted by CopperStateZ51
I am new to the Forum and new to the Corvette. Just got our first, 2006 Daytona Red, Z51. After having an S2000 there is really no comparison. First long trip I had to see what she could do. Found a straight stretch of highway and noone in site. Everything was great up to 130 in 5th. Plenty of power left so I decided to try for the 150 club. Then it started to drift from side to side slightly but at 130+ it scared the **** out of me! The front end acted like it was floating off the ground. I had to physically correct steering from side to side.
I have had our S2000 up to 130+ and it was solid as a rock! What scared me then was I thought the canvas top was going to blow right off. The "only" modifications I have done is Z06 replica wheels from West Coast Corvette. I kept the same run flats so they are a little narrow for the wheel but they were still within range.
I go to the dealer next week and this is the first topic I am going to bring up. Problem is, I not sure how he's going to diagnose it
I have had our S2000 up to 130+ and it was solid as a rock! What scared me then was I thought the canvas top was going to blow right off. The "only" modifications I have done is Z06 replica wheels from West Coast Corvette. I kept the same run flats so they are a little narrow for the wheel but they were still within range.
I go to the dealer next week and this is the first topic I am going to bring up. Problem is, I not sure how he's going to diagnose it
2. Add Z06 shocks on all 4 wheels (leave Z51 sway bars in place).
3. Tires should be 32 PSI, cold.
This will likely cure your problem. if not, go back to the stock rims.
Last edited by AraiGP4; May 28, 2006 at 09:55 PM.
Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
Originally Posted by CopperStateZ51
Maybe I confused my Vette by calling it red.. Anyway, I will get the alignment checked but still think any car rated at a top speed of 180+ should be rock solid at 130.
Car needs to corner balanced with the drivers weight in the seat.
With out the proper rake and agressive alignement the car will wiggle and and you will feel lift above 130 mph.
Tires have a lot to do with high speeds as well. Dont believe the street tires rating of Y or Z, that is a load of crap. Road racing slicks for safe driving at high speeds and please do it on a race track, not the public roads.
The corvette is a great car, but it is not set up for high speed driving at the factory.
Pro
Joined: Apr 2005
Posts: 535
Likes: 0
I have a Z51 been very fast in it... I had the alignment redonce at the delaer before I took possession. No issues here. don't worry, the car is great, just have the alignment done by somone who knws vetts.
Also, you maiight be able to get the delaer to do it if you ask nicely.
Also, you maiight be able to get the delaer to do it if you ask nicely.
Race Director
Joined: Mar 2005
Posts: 10,399
Likes: 25
From: Austin Texas
You've added a wider, heavier wheel to the front and a heavier wheel to the back, the front wheel is the wrong width for the tire and you ask why you have handling problems?
I doubt the dealer is going to do a free alignment with the wrong size aftermarket wheels on the car.
I doubt the dealer is going to do a free alignment with the wrong size aftermarket wheels on the car.
Drifting
Joined: Feb 2006
Posts: 1,250
Likes: 3
From: Honolulu HI
Originally Posted by JohngC62005
don't remember the specs but have them set caster as high as the spec allows and equal on both sides and camber with the left side .5 more positive and kiss your high speed problems good by. Tire PSI for drag 30 cold tires PSI for high speed 34 cold. Tire can loose shape at high speeds with too low of presure. I have yet to find a new car within alignment specs. They are always just close which is fine for every day driving but not for anything high speed.
i would probably up the tire pressure up a little if the high speeds are for any sustained distance
i wish we had any kind of high speed track out here
Last edited by 2LT-Z51; May 29, 2006 at 03:45 PM.
Safety Car
Joined: Dec 2005
Posts: 4,157
Likes: 37
From: North Carolina
St. Jude Donor '07-'08-'09-'11-'12
Originally Posted by 2LT-Z51
i would probably up the tire pressure up a little if the high speeds are for any sustained distance
i wish we had any kind of high speed track out here
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Le Mans Master
Joined: Aug 2004
Posts: 5,414
Likes: 1
From: Just moved back to the "old country"
I've had mine well over 150+ several times and it is ROCK SOLID ... Z51 ... I can drive with one hand its like a sunday cruise ... my guess is (as others have said) alignment issue - which I would check first - if not, it is those aftermarket wheels that could be the problem. A well aligned Z51 with the stock setup is very very solid at high speed.
Racer
Joined: Jul 2004
Posts: 331
Likes: 0
From: Atlanta, GA
I would check the lugnuts and alignment. What size are the aftermarket wheels? Although I wouldn't condone a highspeed run like that on public roads the car, as set up from the factory should do it easily.
Race Director
Joined: Jun 2001
Posts: 10,084
Likes: 3,055
From: CA
Originally Posted by dennis50nj
It means you are not use to the car. The illusion with top down made it seem much worse than it was maybe. it could be the rims, but the steering is very sensitive at high speeds because of the stiff side wall of the run flats. I had the same problem lowered tire pressure. solved problem.12,000 miles no tire wear on front some on rear from 1/4 mile so it was not alignment. plus if you are so educated and speak the KINGS language you should be able to understand my writing. I haven't been in school for 36 six years, and haven't posted 3 to 4 thousand posts, or even wrote a note or letter in my business. but i am at the top of my field , and can afford a corvette with out an education ,or an English degree ,just needed common sense . as i can see you have none. or manners to treat people like you are superior. Sorry to offend you but you offend me sir.
In case you haven't noticed, everyone is a jokester here. I'm sure Shawn meant no offense. You'll get your chance to rib Shawn back or someone else here, too.
Michael
Drifting
Joined: Sep 2005
Posts: 1,775
Likes: 1
From: Rehoboth Beach Delaware
Originally Posted by Michael A
I'd be concerned about these narrower tires. Perhaps the contact patch isn't quite right anymore. Just a thought.
Michael
Michael
Race Director
Joined: Mar 2005
Posts: 11,549
Likes: 27
From: Southampton NJ
Originally Posted by Michael A
Dennis,
In case you haven't noticed, everyone is a jokester here. I'm sure Shawn meant no offense. You'll get your chance to rib Shawn back or someone else here, too.
Michael
In case you haven't noticed, everyone is a jokester here. I'm sure Shawn meant no offense. You'll get your chance to rib Shawn back or someone else here, too.
Michael
Drifting
Joined: Jul 2001
Posts: 1,896
Likes: 3
From: New Bern NC
My Z-51 alignment was off from the factory. Be sure lugs are tight, some of mine were loose. As said check air pressure. I have found the Z-51 to be OK, even thought I have not had it to 150 yet.
