No Go

Does anyone have any experience on installing Z51 Bilstein shocks on a base suspension car (specifically 96)?

My car has been upgraded with 30/26 OEM bars and seems to handle very well.

I have noticed that the car has a tendency to porpoise from side to side in high speed corners (~85-and seems like a nice 4 wheel slide around the corner-fairly dusty here in Nebraska). Now I know I'm not that smooth (might be sole reason:)), but can't help but wonder when are stiffer suspension components recommended. I would like to keep the car soft ride (to a point), but want a stable platform for my learning. The stiffer springs would be more expensive and more labor intensive compared to bolting on set of new Z51 shocks for ~$280.

I thought about having them revalved, but my originals are little tattered so replacement is only a few more dollars-I could always have the new ones revalved when my skill level justifies it.

Also what year shock did you use/recommend as Mid-America offers different models for 89-94 and 95-96. I assume the 95-96 are firmer.

Thanks:)


[Modified by No Go, 10:39 PM 5/17/2002]

Ralph Giro

Call VBP. Tell them what you have and what you want to achieve. They'll recommend. Tell them you want the 10% discount cause you are a friend of mine, Danny Kellymeyer and the Touring Challenge for Corvette group. http://www.vettebrakes.com/
Hope it helps.

kkonen

I run Koni SA. They were $480 shipped from Summit. At their softest setting they are about the same as my FE1 stock Bilsteins.

MSR

bilstein sports don't kill the ride, and they work well. i'm using them with my current springs (1125#f/540#r), but i installed them when i still had the base '96 springs (and auto-xed it like that), so i know how they act.

with the current springs they seem to lack rebound, but they fit the stock springs well.

h rocks

Unfortunately, the 96's were the softest sprung and damped of all the C4's. If you want the firmest of the production run C4 shocks, then probably the '89-'91 Z51 shocks are the ones. But, if you have two weeks, just send them to Bilstein for a re-valve, and for ~ $220, you will have a new set of "custom" valved shocks.

I frankly don't know how compatible that combination of shocks and springs would work out. The super soft springs will allow the suspension to compress easily, but if there's too much rebound control, then the suspension will be very slow to recover from full bump, for example. I would talk to the Bilstein guys in Calif. and get their thoughts. Bilstein worked with, and developed the shocks with GM specifically for each of the suspension variants. I have had excellent results working with them over a number of years. I avoid the "one size fits all" mentality of many of the Corvette parts sellers. There are a number of them IME, that are standouts however.

No Go

Oops made a mistake in above post..."the 89-94 shocks would be firmer" not the 95-96.

I have looked at adjustable shocks before, but not being able to adjust them on the car kind of ruined my enthusiasm for the price. Think I'm going to stay with plain bilsteins.

When I spoke to Bilstein about revalving-they mentioned the basic service is $55 each plus any parts. Sounded like if you had some miles on them they would require parts. There by becoming much closer to set of adjustable Koni's.

The car does have alot of body movement. When at the track and using most of the traction the 275/315 Pilots provide, I notice it. Even on the shifts the car will drop the nose visibly similar to hitting the brakes (nosedive). I feel like I'm accomplishing something, but in reality it is not the fastest way, I imagine.

I'm thinking of getting new set of Bilsteins and then revalving at a later date, especially considering I don't know how 'serious' this will become. I don't want to run Z07 type springs, but it may happen as you know how speed is addictive...:)

Thanks for the inputs.

No Go

Anyone else???

:)

gcrouse

To get the handling you're looking for you've gotta change the springs and shocks both. If you get new shocks or have yours revalved to Z51 damping, you *might* be ok; but understand it's a bit much for those mushy springs. Compression is ok (working with the spring) but the rebound (working against spring) will overdamp the extension, and you might drop like a rock when the road falls away. I drove mine for a while like that- awfully hard on the kidneys, and can upset the balance of the car.

Since you're thinking of buying new and revalving later- here's an idea: Install new Z51 Bilsteins and try them; if they work- cool- start saving up for springs. If they're too much then rebuild / reinstall your old ones with your current springs; save the Z51 shocks until you get the springs. Same amount of money.

Final thought- the porpoising you're describing could be soft front spring + low front compression damping + low rear rebound damping. There might not be anything actually wrong with your current shocks...

LT4 FTD

If you want a small improvement in feel for a small decrease in ride comfort, do the Z51 shocks and springs. Unless you go to the koni sports, you won't notice much difference with the shocks alone.

A few years ago I was in the same boat- base Z51 suspension wanting more performance. I talked to a couple guys with way too much shock experience, and for my application- stock class autocross- it was either gonna be let someone revalve a set of Bilsteins and hope they hit what I wanted, or get Koni's and adjust them myself. I went with the Konis. They made a huge improvement in the car's slalom performance, and slowed the pitching a bit. They also took the cadillac like ride and made it a little harsh.

Looking for more performace I went to Z51 springs- mainly to get the 1" wider front wheels legally for stock class. They made the ride a little harsher- not much- the shocks were a much bigger difference. Slightly reduced body motion, but this puppy still leans pretty heavy in a hard turn, rises significantly on the gas and dives hard under braking.

Corvettes have pretty good suspension geometry and all this movement really isn't that bad, but many drivers don't like it. And how fast a car goes depends ultimately on how comfortable the driver is with the car. Getting the right shocks and/or springs will improve the car slightly, but might improve your confidence in the car greatly and make *you* much faster.

I'd recommend going ahead and buying a set of Konis- compare a few minutes to pull the shocks and adjust them to what you'd need to do to change the Bilsteins: pull the shocks, put your old ones back on, ship them out with some $$, wait a few weeks, get them back, remove the old ones, put the new ones on, try them and if you don't like the change repeat. By then you might not remember real well what the car was doing when you sent them off. Plus the Konis you can adjust to your new springs when you buy them. Trust me, eventually you'll upgrade the springs. Or you could just go nuts now and buy a full coilover kit.

Really you should try to drive a few Vettes with different suspensions and see what you like and what you don't, then decide for yourself.

Justin

HiRiser

I'm running Bilstein Z51 shocks on my 93 FE1 and I like it. Ride is alot more controlled without any increase in harshness. As a bonus, I figure when they wear down they'll still be better than the stockers.

No Go

Again thanks for the responses.

Agreed, I don't think there is anything wrong with the shocks (original FE1 with 75000 miles), but wondered if there was a point where the handling takes a real hit from soft suspension.

After another track night, I'm getting more enthused about making the car perform. I'm getting more comfortable and smoother each time...probably shouldn't do anything to the car but drive...but...:)

My front tires are really taking a beating on the outside edges. My Michelin Pilots (18000 miles) are nearly smooth...not to cord or anything but this shows the wear on outside vs rest of tire...need more negative camber I suppose-running -1.1 each front and maxed out.

I'm now thinking lowering the car with the wedges and equal in rear and adding the stiffer shocks...course now rethinking and maybe just get the Konis. Really wanted to keep the car looking similar to stock-fits my experience level-hate to have a catalog car and not be able to drive:)

By the way, I caught and passed a Z06 and nearly a 98 Viper! That really gets the blood going...

Thanks!

vettes

Nogo, I'm in the same situation. 92 base suspension FE1 suspension swaybars 30/26.Looking at Z51 shocks.Good advice so far.I have to make a decision today.