Suspension upgrades

[vms4evr]

I've got a few questions regarding mixing suspension parts...
I have the base "soft ride" suspension on my92. The car has 90K on it and it is all original suspension parts.

1st - I'm looking at the Bilstein Sport shocks. I think the car comes with ones listed as HD. The Sport are supposed to be more aggressive. Part # 1177 and 1178 at VBP.

2nd - Considering thicker sway bars. Like 32mm front 26mm rear. Maybe a little smaller.

3rd - Replacing a bunch of the rubber bushings with poly on the front and rear. Some of mine are rotting out and squeezing out. So I need to replace them with either new rubber or go to poly.

Now I'm getting mixed feedback on what happens when I do this. Without changing the FE1 springs are the Bilstein Sports a bad idea? I'm confused as to why the shocks would be so bad.

On the sway bars I got very different opions. One side said they will make the car flatter period. The other side says no way. The car will handle worse than stock by using the wrong shocks and thick sway bars.

I'm no suspension guru so could you folks give me some opinions and explanations of why or why not on those changes.

Thanks, Graham

 

[vader86]

I would go with the Bilsteins, poly bushings and a 30mm front bar, if you want Z51 springs put them on the front.

I wouldnt do jack to the rear springs because that effects ride quality considerably, and the bigger rear bar just doesnt feel right (rear wants to come around).

 

[ErnieN85]

I'll second that. did upgrade to z51 shocks. big help, same with poly bushings. I did not see any degradation in ride. of course i like it real hard!

 

[Tuna]

What are your desires in the car - better ride? Better autocrosser? Firmer feel for the street?

I support the Z51 shocks and replacing any bushings, etc. that are worn.

Bigger sway bars will help with body lean and turn in. However, they should balance each other.
Here's the deal on handling:
- bigger front, same rear = more push or understeer
- bigger rear, same front = looser or oversteer (rear wants to come around as was stated before)

Going with a bigger front bar will reduce the lean and improve turn in usually. It will make the car more stable as it forces more understeer. Not good for autocrossing.

If you change the bars, keep them in balanced sets for best handling.

Z51 shocks and the Z51 bars from the 96 are a good combination even with the base springs.

That's my 2 cents.

 

[JimmyS5600]

I enjoyed reading all the opinions on this topic. Iam very happy that my CE has the Z51 package. What upgrades do you folks recommend for a Z51 package?
Thanks.

 

[vader86]

For Z51, id do poly bushings and maybe a bigger front sway bar, and just make sure your shocks are good.

This is what im doing for mine.

 

[vms4evr]

Thanks for the ideas guys. I'm trying to acheive 2 things here. I guess I should have stated that first...
The car has over 90K now. So part of this is to replace worn parts. The other part is to improve handling for autocross. This is Solo II low speed.
So new shocks were near the top of my list. Vette Brakes and Products has the Bilstein Sports for $300 for all 4. I can live with that. So I looked at what they had and thought I might upsize the sway bars. Bit I remembered reading that the shocks would be fine but sway bars had to be matched to the car. The springs I'm not going to touch.
I grabbed the suspension info for 84-96. I noticed on my92 that they used 26T/22S sway bars on FE1. Then 93-96 they kept 26T in the front and went to 24S in the rear. So maybe they figured something out with the 92 to make that change. So if I follow that logic and get a 24S for the rear that will help a little with the roll. So is this a negative or positive for autox??
Also on the poly bushings. Are there any in particular that I want that makes the most improvement. Like sway bar bushings in poly or trans mount etc.. I'm not sure I'm capable of replacing all the bushings in the car. So I figure I'll do the easiest and most effective that are reasonable to do. Any in particular?
That should keep me busy for a while...
Thanks, Graham

 

[vms4evr]

I have the new Bilstein Sport shocks coming in tomorrow and will put them on Saturday.
Anything I should know before I start to avoid painful surprises? I've done the front ones before and that is easy. What about the back. Looks kinda tight in there on top of the shock.
Graham

 

[vms4evr]

Just an update. I installed the Bilstein Sport shocks (Z51). I like the ride. The car is firm but not bone jarring. Even though the original ones weren't leaking or anything they were soft. The car feels a little tighter. So we'll see what happens this weekend. I have an autox on Sunday.

Btw, For anyone who is interested. Replacing all 4 shocks is fairly easy. Just remove the wheel so you have more room and use 2 jacks. 1 for the car and 1 for the suspension. It makes getting the shocks ligned up really easy. Also the new Bilsteins have and allen key hole in the top. So you don't need to grab the top with vice grips to get the nut tightened down.

I'm looking into the bushings next for the sway bars at least and will see how I like it after that. Then maybe I'll do sway bars.

Graham

 

[WhalePirot]

Rubber isolates many vibes from the road but allows the geometry to change. The car wants to move around with suspension travel as a result.

Poly transmits more vibes but keeps things in place during suspension travel; hence the car stays where you put it in a corner.

My heim jointed Z-51 '84 tells me about every pebble on the road, but is VERY stable and predictable vs a stock Vette. I installed Dick Guldstrand's suspension parts at 20k miles or so, and have 105k mles on the car, so they're durable, too.

I think the poly is a perfect compromise for a street/autocross car, at a modest price. My poly is older and should be greased from time to time. I feel an improvement in the suspension's working after I clean and grease. Newer poly claims not to need greasing but I defer to another with experience with the product.

The stock Z-51 Bilsteins never pleased me, ridewise; the GS valving is much better (mine were redone by them) , but I'd like more dampening. Also, I like the stiffer Z-51 rear spring better than the Guldstrand, softer spring.

Who likes it hard?

Mike

 

[vms4evr]

Well I followed (rrubel) rich's advise on the vendor and went to www.suspension.com
Very nice guy and helped me out. I got the sway bar bushing kits with end link bushings for front and back. Energy Suspension bushings. Cost was about $35.
I managed to get the bar bushings on without too much difficulty. Then end links will have to be pressed on when I get chance. Just doing the sway bar bushings has an affect. Before I did them my car would squeek over every speed bump. Now no noise at all. When I pulled the old rubber bushings off they had sand/grit inside and had literally sanded the sway bar so that is was really shinny. Cleaned it up. Used the supplied grease and quiet as can be over speed bumps.
Once I get the end link bushings on I'm done with the suspension for a while other than the VBP advanced street alignment adjustments that will be done.
So far so good.
Graham