need help....suspension woes!!!!

[xbmwguy]

hey guys doing my final finish up on the beast before headind out next week to octurbofest. heres the problem i did the front end with rebel racing bushings and new 22 mm torsions, and sent struts to bilstien for revalving.no problems this week i tackled the rear with new smart racing poly graphite bushings,from clint, and coil over helpers from rebel and new sport bilstiens. got everything back together and did as clint said by not putting any load with the coil overs at first then dial it in after i roll the car and settle it.with no load on the coil overs and my stock torsions lowered about an inch and a quarterthe car bounces like a ricer car with cut springs. talked to clint again and he said put some load on the springs and see if it helps, i did and it did a little. my question is at 25 inches at center of wheel well is not that low where sport shocks should still be in their operating zone. the car has very little dampening effect. help i need to sorrt this out soon as i am supposed to be corner balancing and aligning on mon/tues....thanks frank

[jwasbury]

Originally Posted by xbmwguy

the car bounces...the car has very little dampening effect.

sounds like a problem with the shocks to me. I can't imagine what else would cause what you've described. FWIW, my car was lowered to 24.5" rear fender heights and its very nicely damped on the new Bilstien Sports. Its riding on 29mm torsion bars and the factory 16" wheels.

[xbmwguy]

hey jake just talked to pete and he and i agree i am gonna swap out the sports for my stock hds and see if she still bounces

[A930Rocket]

Frank,

jacob beat me to it.

I was just about to say the shocks need to work with the torsion bars/springs to dampen the occilations. Sounds like your new ones aren't valved right, are defective, etc.

Jim

[Flieger]

What kind of dampers? Clint re-valves Bilsteins.

[JFairman]

I wonder if the nitrogen gas inside the shock may have somehow been compromised or leaked out when the groove for the lower coil spring hat was machined into the rear shock bodies.

If I understand everything Frank told me these new Bilstien sport shocks worked fine and damped really well when he installed them before removing them to have the machine work done.

The nitrogen gas pressure that is seperated from the oil in the shock by a floating and moving dividing piston keeps pressure on the oil in the shock so it does not become aerated over high speed rough road surfaces, and may also affect the rates of the compression valving dampening and the check valve and oil flow valving during rebound dampening.

As an example to relate to this.. If you let the 300psi of nitrogen gas out of a Fox Racing Shock resovoir, all the rebound dampening will completely dissapear.
I know because that is what happened on an '84 Honda 500 Interceptor I have with a Fox Racing rear mono shock.

[911st]

What diameter rear tires do you have with your 25" fender?

It could be possible you are hitting the bump stops.

For a lowered car it is suggested to cut down the bump stops.

See: http://www.smartracingproducts.com/pdfdocs/bilstein_rubbershock_rear.pdf

I am not a suspension expert but for several reasons I really do not like the idea of helper springs. I know Porsche did it to get around some racing regulations once.

Better to get proper sized rear torsion bars or just run coil overs.

If you want to be unorthodox. Up size the rear torsion bars or coil overs enough to eliminate the rear sways. This will keep the car balanced in the corners and reduce squat under accel and braking.

[911st]

Also maybe check the top of the rear shocks that they are tight. If loose enough there is no shock effect over a short range.

[xbmwguy]

Hey guys thanks for the help. When I pulled the sorts with coiovers last nite I found I had left the huge bp stop in which had wedged itself into the upper hat Once removed everything is f#### awesome. Clints stuff rules. Car is handling better than I imagined and I havnt done an alignment or corner balance. Can't wait!!!!!