Help with Oversteer - Lateral-g Forums

Bill71 · #1 08-19-2016, 01:59 PM

I need some help adjusting my suspension. I have a 1971 Camaro with a full cage, LS7, T56, Speedway 9" with Speedtech Torque Arm rear. The front has 700# springs, Viking double adjust shocks, GW uppers, Hotchkis hollow bar. The rear has Ridetech single adjust coilvers. I use my car on road courses exclusively, no autocross. Tires are NT01 with 275/35-18 front and 315/30-18 rear. I have been running the car since January and have had a bit of understeer from the beginning. I have always had a bit of tire rub in the back so I changed out the 225# rear springs to 300#. i had the car on a local track last Saturday and had zero tire rub but the car was noticeably tail-happy, at one point causing so much oversteer that I put all 4 wheel in the dirt. When I changed the springs I also raised the rear about an inch at that time. I am thinking that I can lower the rear ride height and maybe add rear tire pressure and soften the shock adjustment to help with this. Am I on the right track?

**Tinker** · #2 08-19-2016, 08:13 PM

I should let this for the more experienced, but refer to Ron Suttons sticky on overall handling in this section. #12 "more spring = less grip". This is exactly what happened when spring rate was increased. Also increasing tire pressure acts like increasing spring rate, effectively compounding your issue. Let's hope some others can chime in to tell you what you should do, because there are a lot of people with great experience on this forum.

Vegas69 · #3 08-19-2016, 08:26 PM

I would say less spring rate and a dual adjustable shock. An inch of ride height change is HUGE. Corner weight the car when you reduce the spring rate. Make sure you have that rear shock close to mid stroke. Otherwise you take the risk of bottoming out the shock in compression or extension. Either way, no bueno.

Z06vette · #4 08-19-2016, 08:31 PM

I have found this to be true as well. My car tends to push on the autocross. The more I dial up the rear shock setting, the better the car turns. Softening the setting creates more push. I also dont like the mismatched types & brands of shocks. But I have no business making suggestions, as I am no expert by any means. Just relaying my experiences. Why not put the softer springs back in and just raise the rear ride height to help with tire rub? Where is it rubbing? Can you roll the lip? Or maybe a 250lb spring is the sweet spot for you?

Bill71 · #5 08-19-2016, 09:32 PM

I will look for Ron's suspension post. Regarding air pressure I actually lowered it in relation to the front. I have different brands of shocks because I bought the Speedtech parts first then the Viking shocks became available later. The tire rubs mostly on the inside of the rear wheel wels as I did not mini tub the car. The 300# springs definitely helped that problem and the new handling characteristics do make the car change direction faster. I just want to dial it back a bit if I can do it without buying another set of springs. I will probably start with lowering the rear a bit and it sounds like softening the shock setting is going in the right direction.

Rod P · #6 08-19-2016, 10:10 PM

its tough to give proper spring recommendations without corner and vehicle weights....but i also dont like mixing the shocks, the two have different compression and rebound curves, not to mention that the Viking is a digressive piston twin tube double adjustable shock, and the ridetech shock is a linear piston mono tube rebound adjust only shock (unless it is brand new then it might be the new digressive piston ones) so they react completely different as the flow thru the shock oil

there is so much that needs to be discussed before a base can setup can be designed

Ron Sutton · #7 08-21-2016, 11:20 AM

Quote:

Originally Posted by Rod P

its tough to give proper spring recommendations without corner and vehicle weights....but i also dont like mixing the shocks, the two have different compression and rebound curves, not to mention that the Viking is a digressive piston twin tube double adjustable shock, and the ridetech shock is a linear piston mono tube rebound adjust only shock (unless it is brand new then it might be the new digressive piston ones) so they react completely different as the flow thru the shock oil

there is so much that needs to be discussed before a base can setup can be designed

I "think" the only Ridetech singles with digressive pistons & valving are the ones they do for me. But maybe someone else is having them do some for them too.

.

Ron Sutton · #8 08-21-2016, 11:23 AM

Quote:

Originally Posted by Bill71

I need some help adjusting my suspension. I have a 1971 Camaro with a full cage, LS7, T56, Speedway 9" with Speedtech Torque Arm rear. The front has 700# springs, Viking double adjust shocks, GW uppers, Hotchkis hollow bar. The rear has Ridetech single adjust coilvers. I use my car on road courses exclusively, no autocross. Tires are NT01 with 275/35-18 front and 315/30-18 rear. I have been running the car since January and have had a bit of understeer from the beginning. I have always had a bit of tire rub in the back so I changed out the 225# rear springs to 300#. i had the car on a local track last Saturday and had zero tire rub but the car was noticeably tail-happy, at one point causing so much oversteer that I put all 4 wheel in the dirt. When I changed the springs I also raised the rear about an inch at that time. I am thinking that I can lower the rear ride height and maybe add rear tire pressure and soften the shock adjustment to help with this. Am I on the right track?

Like others have said, raising the rear an inch is a HUGE change.

Lower the car back down & run it. If you find you still need more rear grip, lower the rear panhard some. If it is too tight again, you can raise the rear a little, or raise the rear panhard bar ... or both.

Bill71 · #9 08-22-2016, 10:15 AM

I need to correct what I originally wrote. I probably raised the rear about 1/2 inch. I will lower it just the same. Ron, the panhard bar is already at it's lowest position.The Ridetech shocks are single adjustable in both rebound and compression according to Speedtech's website. If it is possible to answer this question, would it be worthwhile to just bite the bullet and get Viking shocks for the rear? I do not want to drop another $150 for another set of springs.

Ron Sutton · #10 08-22-2016, 08:08 PM

Quote:

Originally Posted by Bill71

I need to correct what I originally wrote. I probably raised the rear about 1/2 inch. I will lower it just the same. Ron, the panhard bar is already at it's lowest position.The Ridetech shocks are single adjustable in both rebound and compression according to Speedtech's website. If it is possible to answer this question, would it be worthwhile to just bite the bullet and get Viking shocks for the rear? I do not want to drop another $150 for another set of springs.

Perfect. Lower the car back 1/2" & run it. If you still need more rear grip we can explore other options.

I'm trying my best to not sound like a smart ass. I really am.

But why would you want to change from Ridetech shocks to V....

Never mind. Changing from a monotube shock like the Ridetech to a twin tube shock like the Viking would be a disadvantage. So don't do that.