One of my vettes is a 1994 coupe. The car is all original except for normal wear items such as shocks, tie rod ends and tires. I am looking for some help with the ride.
I love the car but it rides like a log truck. After purchasing the car I replaced the shocks with billestein but the ride did not improve (handling was good though). I recently changed the shocks to AC Delco stock, but again no ride improvement noted. I replaced the tie rod ends, got an alignment and checked the ball joints (ball joints were good). Still no
improvement on the ride issue. The car has stock size tires and has not been lowered.
I love the car but hardly drive it due to the harsh ride. I want to keep it stock so I do not want to replace the springs with coil overs. Does anyone else have this issue with their C4? I would appreciate any advice.
Thanks in advance.

 

New rubber bushings?, and what suspension package does it have in the RPO codes?

Ride quality is affected more by the rear spring rate, if you have an upgraded suspension you can go to a base spring. Thats about as good as you're going to get.

 

Thanks for the response. I didn't find any issues with the bushings (doesn't mean they may not be bad though), they are rubber with 80K miles so could be the problem.
Suspension RPO is FE1 base suspension.

 

How old are your tires? When I bought my 96, I replaced the shocks just because they were old. Car was more planted/stable over sh1te pavement but didn't notice ride difference. Replaced the tires, just because they were old. Didn't expect this, but tire replacement made my car ride better and quieter. The front tires I replaced looked fine, but one was 17 years old and one was 20 years old. I guess they were pretty hard.

 

You might try lowering the tire pressure 3 - 4 PSI and see if that makes any difference. Are you by any chance running runflat tires in the 94?

 

My tires are not old. Bought them about six months ago. I don't think lowering the tire pressure will help my particular issue as it rides really rough but thanks for the suggestion. It very well could be bushings. Even though they look fine from the outside just based on the age they could need replacing.
That may have to be my next project for the C4.

 

I encourage you to at least try lowering your rear tire pressure. Try running 27-28 psi. If that doesn't make a difference, I suggest you look at rear spring stamping on the chance it has been swapped.

 

hmmm. thinking. thinking.... I'm just finishing up my suspension woes. When I got the car, it was a distance purchase. The seller just drove it to the occasional car show. When I got the car it was horribly setup. I don't know if its something I caused b/c I don't recall removing anything when I was test driving it. I had to fix a loose steering rack anchor bolt was loose. The worn out bilsteins were mushy, not harsh. The tires were 18 year old oems. One front had dent in it. Then there was the obscene tire wobble. I actually got a Go Pro camera and mounted it with sticky tape inside the wheel well. Yes I also bought the 2 yr no questions asked coverage on it with a silly grin at Bestbuy. Anyways I found the front right wheel had a serious wobble that got very bad at exactly 59 mph. The oscillations were compounding at that specific speed. I thought the wheel fixer guy missed a serious warpage issue.

Moving on with my process of elimination, I started to replace the front brakes with the Z23 system. I got to putting the new rotors on and wtf? they shipped z26 13 inches. back in the box, old rotor back on. After a couple days of fretting with frustration I had to take her on a weekly stretch out. Down the road, 30, 40, 50, 59? No wobble, what so ever. No vibration no harshness. All Corvette right there. The Only thing I did was remove and reinstall the same rotor. BUT I did place it on the ground. I think there was a flake of something caught between the rotor and the hub. I should have put my dial on it, but the rotor doesn't have a lock down screw so its loose fitting. Kind of bypassed tightening it down b/c I already decided the brakes update before and replacing the rotor would have crossed that off the check sheet.

Anyways, reason for posting is persistence pays off, and this particular for me to fix all these issues was a $125 rim straightening. (plus my wear items)

If you can be more precise in your testing, describe exactly how when where types of conditions for the harshness. Oh BTW I know my toe adjustment is a little off and that will add to some harshness, you can feel the front tires if they are warmer than the rears.

Now the car is driving very well and just seems a lot tighter with new seals also. I run lower than 35 PSI, more like 32.

 

I will check out the rear spring stamping to be sure it is correct.
As for a more precise description of the harshness, when I hit a depression or upheaved area of pavement it feels like there is no suspension at all just a hard it.

 

If its like hitting a bump across both sides I would say its stiff springs. If its just one side I would say sway bar. Could be both are altered.

FE1 has a soft ride. For a corvette, its controlled but not harsh at all. If there's a dip, you would definitely have a pretty soft back end. Hard springs can definitely put your wheels at risk especially if they are wide.

 

Stating the obvious here but have you driven many other C4’s as a point of comparison?

 

This is the only C4 I have driven. I do have a C5 (which I drive often) and a modified C3 (which was original when I purchased it) it had the gymkhana (FE7) suspension. It rode pretty rough but did not have the hard hitting ride the C4 has.
I am still leaning toward the bushings. When I get time guess I will pull the bushings and replace them along with the ball joints while I have it apart.

I appreciate all of the advice. I do love this forum as I have learned a lot on here.

 

I know after I changed bushings I had to preload suspension before fully tightening to allow bushing movement versus binding. But if you have original rubber I do not know the odds this is your problem. C4 is known for its harsh ride and usually gets worse as you modify.