I wanted to post this here on the suspension board. I feel it is some valuable information and wanted to share it with you guys too. Plus if someone does a search in the suspension board they will find this too. I will be in 2 more auto-x events to see if my theories are true. Let me know what you guys think. Has anyone else experienced this problem?


https://www.thirdgen.org/forums/orga...nd-my-car.html

 

There is much more going on here, than just the bushing material. There are a lot dynamics going on when you are both turning, and braking. The poly bushing/boxed arm, causes more roll resistance. This is going to have a larger effect on steady state cornering, when you trail brake, you have so many more peices all coming together. With LCA relocation brackets, your geometry is going to come into play the A/S that you dial in for acceleration, is going to work against you when you are trail braking. YOu may also have some roll over-steer dial-in. Under braking this is going to be more pronouched, depending on how the rear unloads.

It sounds like you car is pretty close to neutral with just a slight tendancy to oversteer under steady state cornering. So a slight sway-bar, or shock change, or even eliminating the binding of the poly bushing, may be all that is needed to balance there.

So, there is my non-answer answer. Basicly, there is so much more going on, then just some binding of the poly bushings.

 

Well I have swapped to a slightly softer rear sway bar now and once it quits raining here I will go try it out. I also only have my LCA relocation brackets in the 1st hole and my car sits about as low as many cars with Eibach Pro springs.(springs sag a tad) so I doubt I am getting much if any roll oversteer.

 

Try using poly bushings and un boxed LCA's. Your rear suspension wont bind in cornering.

 

I have boxed and poly. Haven't driven the car hard enough yet to say if it's binds or anything, but i'll let ya know

Poly on one end, and rod end on the other would be best. I'd use a 3/4" dia rod end, with a 12mm"ID 3/4"OD delrin or polyurethane or UHMW bushing. That'll keep it a bit softer than the norm.

 

Too bad you aren't local for this weekends event.
http://www.transamws6.com/pics/SEPT17_ACU4.jpg

This is a test and tune layout. Should be very fun.

 

well I drove the car last night with the small bar on it and it appears it has helped a measureable amount. I'll have to wait till our next event in a few weeks to really try it. With the stock rear bar I can coast into a corner (no brakes or throttle) on the street, turn into the corner and bring the rear end around every time. Usually depending on how sharp the corner is I would even have to start turning the wheel back to correct, This is with no throttle or brakes applied, the car would just tail out!

Now last night with the smaller bar you can go into a corner the same way and the rear end will still come around just a tad, but as soon as you start to straighten the wheel the rear hooks. It does not slide as soon, as fast, or as far as it used to on the street. Again I will try this out at our next event in a few weeks and we will see what happens, but it appears that I have helped the issue. If it does fix the issue then Sam Strano's comments on his site are correct, poly bushings with boxed LCAs increases roll stiffness. People on here say the suspension will "bind" which I feel is a misnomer. Bind to me means the suspension reaches a point where it is hung up or will not move any more. This doesn't appear to be the case if a softer rear sway bar has helped.

 

Bind.....what bind? You guys should try driving a G-body with poly bushings on all 4 rear control arms. There's a picture some where on the monte boards of a car sitting on all four wheels at stock ride height with no rear springs.


I'm going to throw this out here, would you guys be interested in a set of control arms with a joint on both ends that had the freedom of movement of a heim joint with the NVH supression of a poly joint?

 

More details, pics? For me I am interested in everything, but my funds to most of the talking, and right now they aren't silent, but not overly talkative either. Depends on $$$ for me mainly.

By the way, Zepher, that course looks huge! We used to have a course like that at the Toledo Airport, but they leased our space to Jeep to store new vehicles. I love the big tracks!

 

It's a huge lot we use. Unfortunately, the event was pushed to next weekend since the Navy had to schedule hovercraft operations this weekend.