When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Those bushings look interesting. They advertise that they are "zero bind" which means they have angular compliance which is what you need. I suspect that the biggest issue is the rear suspension binding up when you roll and that is causing the roll stiffness to be higher than you expect. If you can get a set that will fit I'd strongly suggest you go for it.
When we were doing our C4 BSP car we looked into going all poly in the dog bones since that was legal, but our inside source who had access to the geometry at the time told us it wouldn't work because it would bind up..
I know these cars are approaching 30 years old and the rubber is shot, but even a set of tired stock arms will be better than going all poly at this point.
I think it's all in the shocks. I want to be critical of some of the driving. But seeing the car behave the way it does in the vidoes and then seeing the pictures. Tells me exactly what I need to know. And that is you will be an extremely happy man when you put some real shocks on the car.
Houston Region has some top notch talent. See if you can get David Heddrick to do a run in your car. Tell him JFO sent you. Let me know what he says about the car.
David and chris stokes both drove the car, I'm sure the shocks will really help too. At the practice event Chris was about 1 second faster then I was, I never got david's times. So do you guys think I should do the sway bars as well?
Poly bushings are really bad. I replaced all of mine with heim joints. That made a huge difference.
Shocks are the final step. Most shock people want you to get the springs and sway bars correct and then use shocks as the final tuning device. Bilstein did my shocks. I have huge rebound numbers. My friends at GM say that I actually have too much rebound but they like to pick on me.
You guys are on the money, the car has monroe sensicrap on there now. I ordered Ridetech adjustable shocks as koni doesn't make anything for early c4's. There is poly in the rear dogbons, I cant find any factory replacement rubber bushings. I did however find these bushings but i need to get some measurements to see if some will fit. The tires are actually 255 hankooks c71, at a $100 bucks a pop they are good to set the car up before going to 315.
Those poly dog bones are killing you. Corvette Central sells the rubber stock replacements, get those. The dog bones have to not only move up and down but twist some too. The poly binds this up.
Also, from your pictures you need more roll stiffness everywhere. My 93 Z07 does not roll half that much, its fairly flat, most of the time. Then again I'm on street tires with big bars and fairly stiff springs.
IDK, anything about the ridetech shocks but they need to match your spring package. If not, they are not what you want. Its a shame they don't have the Koni's avalible for the early C4's, I love my set.
Everyone needs to take Solofast's advice. My 93 is setup more or less by the advice I got from him. I'm very happy. I'm experimenting with minor adjustments and dumb things just to fine tune the car, but the overall package and rough tuning is all based his advice. I'm more than pleased with the car. Given more or less equal drivers, my C4 fears NO S2000 for sure. I've ran with plenty of them, once I get the car fine tuned and on bigger shoes (need those wider 285/35/18 Hankook RS3's) going to be a killer car. Need some extra money however.....
Those poly dog bones are killing you. Corvette Central sells the rubber stock replacements, get those. The dog bones have to not only move up and down but twist some too. The poly binds this up.
Also, from your pictures you need more roll stiffness everywhere. My 93 Z07 does not roll half that much, its fairly flat, most of the time. Then again I'm on street tires with big bars and fairly stiff springs.
IDK, anything about the ridetech shocks but they need to match your spring package. If not, they are not what you want. Its a shame they don't have the Koni's avalible for the early C4's, I love my set.
Everyone needs to take Solofast's advice. My 93 is setup more or less by the advice I got from him. I'm very happy. I'm experimenting with minor adjustments and dumb things just to fine tune the car, but the overall package and rough tuning is all based his advice. I'm more than pleased with the car. Given more or less equal drivers, my C4 fears NO S2000 for sure. I've ran with plenty of them, once I get the car fine tuned and on bigger shoes (need those wider 285/35/18 Hankook RS3's) going to be a killer car. Need some extra money however.....
I agree about the bushings and I understand on how they operate on several axes. Right now I am debating on getting the banski arms, piecing together something myself, or factory rubber. I'm classed in ssm so control arms should be open to whatever right?
I finally got my Ridetech shocks after 2 weeks, apparently they are made to order and they where backed up or whatever. They are Q series HQ (Handling Quality) shocks, mono tube with rebound adjustment. So far out the box they look great and the adjustment **** that has 24 click. I have a set of Koni Yellows on my BMW and the Ridetechs look like better quality pieces hands down. We'll see how they perform.. http://www.ridetech.com/store/1984-1...m-level-1.html
Santa also brought me a 32mm vbp sway bar for up front so hopefully that will help with body roll. It's all a work in progress with a limited time and budget.
Last edited by TurbineSurgine; 12-26-2014 at 11:11 PM.
Poly bushings are really bad. I replaced all of mine with heim joints. That made a huge difference.
Shocks are the final step. Most shock people want you to get the springs and sway bars correct and then use shocks as the final tuning device. Bilstein did my shocks. I have huge rebound numbers. My friends at GM say that I actually have too much rebound but they like to pick on me.
Bilstein did my shocks on my 1992 C4 BSP car. I did not do any of the work to the vehicle myself as I bought it as a turnkey BSP car a year ago. My shocks have very little damper and a lot of rebound. The springs are also very stiff. I have a thick (32mm I think) sway bar on the front but interestingly enough NO sway bar on the rear. The previous owner (who was almost always fasted time of the day in this car and a national champion in Solo) removed the rear bar because of excessive understeer. I think he's right because it is still prone to slight understeer in certain situations. Unfortunately all of this makes the car very unpleasant to drive on the street. But man... with a set of 315/35R17 Hoosier A6 tires this car is an absolute beast at the autocross!
The rear suspension arms still contain rubber bushings while the toe rods are heim-jointed. I would agree that polyurethane is not the way to go.
12-18-2014, 10:40 PM
