cre8fun

I was looking at picking up a C5 just for HPDE events. I've only driven 2 and I'm a bit confused as to the suspension/driving sensation. please understand, I'm looking for input/understanding and not looking to launch a "what's better, a corvette or some other car conversation." secondly, I'm looking for an "I know what you mean and here's the fix.. or its part of the car, you'll get used to it.."

What I noticed is two things.
1) during transition from side to side (like if you were going around cones or sawing the wheel), there seemed to be a disconnect between the steering(the front) and the back. almost a sensation like the rear was wagging and was 1 second behind the front; or like the rear tires were at 10PSI, but they were not. kind of sloppy as opposed to nimble.

2) for a low profile tire, I was surprised at the amount of steering input needed to make a shift and how disconnected it felt.

the two cars I drove were an '01 Z06 with 52K and a '99 base model with 73K.

So I'm eager to hear thoughts. not sure if what I experienced is normal. I know it's not going to be nimble like a miata or cayman, but I was surprised it was a good bit more disconnected than my '01 M5 and that's a bigger car.

I questioned based on what I felt if I would feel confident to precisely place the car on the track, but clearly many are doing that, so something is missing. Thoughts?

FASTFATBOY

If both cars had cheap tires on them, there Is your problem.

I bought my car it had Continental Sport Contact 3's on it and they were ok.

Changed wheels and put Continental DW's on it, car was terrible in transitions...like it was on 4 marshmallows or 4 beach *****.

Took the DW's off and put Michelin Pilot Super Sports on the car....fixed. I feel everything the car is doing now.

Also bad alignments can make the car feel goofy.

cre8fun

possibly. I think both cars had Potenza Re760's on them

I was wondering if the mono leafs were shot from 15 years of sitting under the car. I had contemplated if coilovers were needed to get a somewhat nimble car, but I noticed that most cars discussed in the track threads were still on mono leafs, so I ruled that out as an explanation.

I agree with your marshmallow analogy. nothing felt sharp. the cars felt a lot like an old 70's caddy, but a little more disconnected with the tail on Quaaludes, getting input and following along a second or two later.

FASTFATBOY

Bad wheel bearing will also give this feeling if its loose enough. Not enough toe in on the rear will also do it.

I am tracking a totally stock suspension C5 Z06 on slicks, it's grip level is pretty high and it's turn in crisp. I have a middle of the road track/street alignment with -2.3 front and -1.2 rear camber. Zero toe in front and toe in on the rear....my car turns very well.

Heres a vid, it boogies through the esses. Tires are warm at 4 minutes in.

Bill Dearborn

When I first took delivery of my 97 I found the car had more trailing throttle over steer than my 86 C4 had. I had to work hard to get trailing throttle understeer in the 86 which understeered a hell of a lot. In fact it took me a few days to change my driving style from an almost always understeering car to one that had a a fair amount of trailing throttle oversteer. With a stock setup C5 you will get understeer on corner entry but it can quickly switch to oversteer if you let off the throttle too much. I found that when I turned into a corner that I had to go to the throttle to plant the rear and get through the rest of the turn. There was also enough power to transition to power on oversteer if I got on the throttle too much. Done correctly the car would go through a corner or through a slalom quite quickly. When you enter a corner what it feels like as you continue through the corner the car will tighten into the turn if you aren't using some throttle. All cars will steer into a corner more if you let off the throttle but the C5 and C6 responded more than what I would call normal.

When I went to running wider tires in front and rear the effect seemed to reduce a lot. Once you get used to the sensation you can use the throttle to help you steer through a slalom or corner. A quick lift and reapplication of power will yaw the car into the line you want to follow.

Bill

Soloontario

If you want a sharper responding car put in a bit of front toe out (but don't ever put in rear toe out)

AND0

Everything matters, lame tires, factory alignment, old shocks, and worn bushings.

Same exact thing, driving my friend's 97 base model, the car is unresponsive and down right ill handling. It has hard tires, factory alignment, original shocks, and 20 years of use.

Same exact thing when I first got my 01 Z06.
However after some work on my car, I have now replaced the tires, shocks, tie rods, balljoints, replaced the A arm bushings with Polyurethane, and a performance alignment. It is a huge difference.
My Z06 my is now the best handling vehicle I have every driven, and it will our corner, out slalom, out grip the M5 or almost any other car, and I love it,
BUT
the M cars have better steering feel then the C5 Corvettes
I know this is a sore spot with my fellow Corvette partisans, but it is one weak point our car has.

cre8fun

thanks for input everyone.

odxr

If you buy a used car the wear items(shocks,ball joints,bushings,wheel bearings) need to be brought up to as new condition before anything else is done.If you use the car on the street its best to get some used wheels and put track tires on them.You can find alot of parts on Rockauto.com-many of them oem spec.

rigit

check your alignment, I see toe mentioned, and yes it matters. I run it at 0 because street driving tire wear compromise. a little toe out will help response, but also will make the car follow all the road irregularities. but also caster is a big one that affects how the steering response feels. the less you have the more responsive, and twitchy. the more you have the less responsive, but will be smoother for track driving. AX guys usually max it out because they are sawing the wheel so fast. if you do more track stuff, Id dial it down just a hair from max.

FASTFATBOY

So you're saying he needs to spend $2,000 to change suspension parts that may be just fine because he bought a used car?

Rubbish.

I bought a 2003 Z06 with 48k miles, checked it over and started tracking it. These cars aren't Kia's, they have high grade parts in them from the factory.

cre8fun

OK, my take away: First and foremost, I'm glad the answer has not been, "nope, they are just like that, but with the fat tires, they hold their own on the track and the horrible relationship between steering feel and suspension is just what creates that added level of excitement on the track." that would have been a horrible answer, but wow, the two cars I drove provided a horrible impression.


It sounds like as long as I get a decent car (50-80K miles) and check out all the wear items in the suspension for play / cracked rubber, etc, then I should have a good base. fRom there, add good tires and research the forum for some decent track alignment specs, I should be a long way towards a decently handling car. from there, there are options. Shocks likely early on. possibly sway bars or removing some of the rubber/play in the suspension. (yes, I'm limiting my discussion to suspension. I know there is a need for other things like oil cooler, radiator, etc) and in an ideal case, I'd buy a car with that stuff already done.

in any case, I will take away that the car, with relatively little cost can be made to work well on the track and not have the train wreck handling I experienced.

Reggie Dunlop

This ^^^

Bill Dearborn

He definitely needs to check all of that stuff. No matter which brand car you have with that number of miles and with the age of the cars everything should be checked. The 99 is almost 18 years old and there is all sorts of stuff that just falls apart due to age.

Bill

FASTFATBOY

I never said he shouldn't check it.

But to drop it off at a shop and say "change every bushing, ball joint and tire rod it has" is ludicrous.

strano@stranoparts.com

Easy. Better shocks. Shocks rule transition response and roll rate. Sure tires are a factor as are other things. But what you describe is simply the two ends not playing nicely with each other.

FWIW, this is why I'm a fan of shocks that adjustable damping so YOU can play with an manipulate how the shocks behave. And you can do that based on things like a tire change (and we do).

For example, the DW's are not a super stiff tire. That slows response of the car, more shock helps gain back response. So then you put on another set of tires, and that all changes again. Suspensions are more than one thing. But yeah, that's pretty classic shocks, lack of rebound control.

370camaro95

One thing I had to get used to in a c5 was the c5's sensation of oversteer (or driving characteristics in general) opposed to my 4th gen camaro. In the c5 you are basically sitting right in front of the rear wheel, in the camaro I was almost equally in between the front and rear wheels, so your sitting further back in the c5 vs other cars.

theseal

Just check your parts for wear, and do an alignmemt. A c5z needs nothing to flat haul *** suspension wise, and only understeers or oversteers if something is way out of whack or the driver is causing it.

quick04Z06

"Potenza Re760's on them"

These tires are one of three tires made in the OEM Z06 sizes. The other two are the OEM Goodyear F1 Supercar (220 AA) tires and the Michelin PS2 tires (220 AA).

The RE760s are very hard--340 AA tread rating. Terrible, hard tires for the track and surely awful in transitions. Cruiser tire.

I would upgrade to a decent dual purpose tire, like the PS2s with a 220 AA treadwear rating. Great street tire, decent for a track rookie. Have them professionally mounted and dynamically balanced.

Make sure you have a solid 4 wheel alignment for track duty. Individual preferences vary, but to start out I would add as much negative camber as you can within the specs and get your alignment professional to give you any other suggestions.

I would also bleed my brakes and make sure you have plenty of brake pad left. Will not affect handling so much, but critical.

Inspect your brakes and suspension parts for wear and replace anything that looks worn out. If you have to replace worn shocks, the OEM 2004 Z06 Sachs shocks are a nice choice.

Have fun and take it slowly as you gain skill.

Bluefire

Bill,

This is one of the best descriptions of the weight transfer "feel" I've read. True gold. Thank you.