Need Rear Suspension help
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Need Rear Suspension help
OK, I lowered my rear a few years ago using the longer bolts.
But when I get the car lowered to a point where it makes the mod worth while, the car will bottom out on the bump stops in the rear going over a dip in the road.
What are my options?
I am considering picking up a set of QA1's to try to stiffen the rear a bit or Vette Brakle Products sells a mono spring as seen below
Any ideas?
Name: Rear Dual-Mount Spring System 1984-96
ID: 42601
Manufacturer: Vette Brakes & Products, Inc.
Desc: Now you can 'dial-in' the handling and ride you want. This unique system allows independent rear wheel adjustment of ride height and spring rate.
Price: $619.95
But when I get the car lowered to a point where it makes the mod worth while, the car will bottom out on the bump stops in the rear going over a dip in the road.
What are my options?
I am considering picking up a set of QA1's to try to stiffen the rear a bit or Vette Brakle Products sells a mono spring as seen below
Any ideas?
Name: Rear Dual-Mount Spring System 1984-96
ID: 42601
Manufacturer: Vette Brakes & Products, Inc.
Desc: Now you can 'dial-in' the handling and ride you want. This unique system allows independent rear wheel adjustment of ride height and spring rate.
Price: $619.95
Melting Slicks
Joined: Jan 2002
Posts: 2,238
Likes: 4
From: Milan
I don't want to steal your post, but i think that what I 'm saying can help you too.
All corvetteparts supplier (ecklers...corvettecentral, mad...) sells two kind of rear spring. I think these rear spring are all VBP.
(Vettebrakes also sells these rear springs)
One is "stock" the other is "sport" called.
There is someone that know the rate of these springs?
i read somewhere that the Sport one is really stiff (like or more than a 84 setup!!)
Probably the "stock" one is the right one I'm searching...
-Beppe-
All corvetteparts supplier (ecklers...corvettecentral, mad...) sells two kind of rear spring. I think these rear spring are all VBP.
(Vettebrakes also sells these rear springs)
One is "stock" the other is "sport" called.
There is someone that know the rate of these springs?
i read somewhere that the Sport one is really stiff (like or more than a 84 setup!!)
Probably the "stock" one is the right one I'm searching...
-Beppe-
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Originally Posted by JCAIRE2
I'd give the guys at VB&P a call. They should be able to suggest a fix. They have always been very helpful to me.
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Originally Posted by VetteNoob
Have you tried a Z51 spring off of an 84? Those are a lot stiffer and may flex less.
I like having the car lower, looks beter, but I had just raised it back up until it stopped bottoming out, now I think I will bite the bullet and do the real fix.
I am leaning toward the QA1's in hopes that the shock can be adjusted to prevent it from hitting bottom, I am surprised no one else has this issue.
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Melting Slicks
Joined: Aug 2004
Posts: 3,003
Likes: 89
From: Indy IN
Pretty much everybody that is running a B Street Prepared C4 in autocross has run up against this issue. The stiffer rear spring will help some. We had the fully double adjustable $500/shock koni's on the car with the 84 Z51 spring and we still ended up hitting the bump stops. It is a fact of life. Some folks have run really big spring rates in the back to get around this, but it isn't anything that you can run on the street. You need to be careful about rasing the rear spring rate too much along with too stiff a rear sway bar. That combination will result in the rear end jacking in cornering and it is really dangerous. If you go to more spring than the 84 Z51 you need to start to soften the rear bar. Go to the corvette action center web site and look at the spring and sway bar combinations that were available. Find out the rate of any spring that you are going to get and make sure you match it to the front spring and swaybar package. If you get the roll stiffnes match from front to rear out of whack the car will oversteer or understeer like a pig. If you are running the car on the street only I would suggest that you stick with the 84 Z51 spring and a softer rear bar.
Melting Slicks
Joined: Jan 2002
Posts: 2,238
Likes: 4
From: Milan
Originally Posted by Solofast
........ I would suggest that you stick with the 84 Z51 spring and a softer rear bar.
I'm now using a real 96 soft rear spring on my 90, with a 26 solid rear bar. (BTW I have 335/17 on the rear..)
During aggressive corners the car does not lean, so I HAVE NO CONTACT fender to tire.
-beppe-
Melting Slicks
Joined: Dec 2000
Posts: 2,719
Likes: 60
From: Fremont Oh
I beleive the stock spring rate is arount 175 pounds per inch. When I first installed my QA1's the shocks were too short ( another story)but I had the situation where I was hitting the bumpers as well. What I wouls suggest is order a "new" sett and trim off about an inch to give you more travel. I think at the time I was at about 25.5 - 26 inches at the center of the wheel well to the ground.
I now m at 27.5 on a full tank of gas using 200 pound per inch springs with the QA1's i do not bottom out and it still looks very good... (as posted I have run as high as 300 in the rear...
Visit my site I hve the part numbers from Summit if you are interested on the site.
Any questions feel free to email or "whatever"...LOL
Mo
I now m at 27.5 on a full tank of gas using 200 pound per inch springs with the QA1's i do not bottom out and it still looks very good... (as posted I have run as high as 300 in the rear...
Visit my site I hve the part numbers from Summit if you are interested on the site.
Any questions feel free to email or "whatever"...LOL
Mo
