rear suspention

[westypoo]

hi all. im looking for some good advice on what i should do for my rear suspension. i have a 75 super beetle. i track it from time to time. so when i built the car, i decided to get rid of the rear torsions and use the uniball setup and coilovers. the coilovers i had, the shock body was too long along with using a 2 inch spring also left no room between the irs arm and the cv boot. the coilovers i was using had 550lb. spring rate witch seemed to work good. but after a few miles the lower shock brackets where cracking cause the shock was just in an awkward angle/ more or less bottoming out a lot. so i cut everything out and i plan on redoing it. i would love to find a motorcycle rear shock size as that bacilly bolts up into a beetle with lots of clearance, but finding one with the proper spring rate is almost impossible (been searching for the last 2 days). i want a car thats adjustable. so for simplicity ive pondered just switching back to torsions and getting adjustable spring plates for now, then later get those really nice atom adjustable ones. was also thinking of getting a center torsion adjuster as well for even more adjustability. your thoughts? i guess im asking do it just keep what i got, fab up new shock brackets, and buy shorter shocks and call it a day or put it back to torsion setup?

heres a pic of my car just for viewing pleasure.



here was my old setup...

[modernbeat]

Bottoming out the shock will, as you found, damage everything in the load path. The upper and lower mounts and the actual shock.

Aside from the standard suggestions, like swaybars, bushings, and Kafer bar, this is what I'd do.

I'd suggest adapting a set of longer Bilstein ASN shocks with appropriate stroke. Mount them so they don't bottom out (or top out). Your uniball mounts get you toe adjustment. Add these parts from Ireland Engineering made for an E30 for camber adjustment without changing ride height.

http://www.iemotorsport.com/bmw/E30-sus ... -lock.html

[westypoo]

i dont really understand what or how these camber things work.....

[buildabiggerboxer]

They must work like the race 911 adjusters by moving the inner pivot up or down for camber control, the bracket is slotted vertically to allow the camber variations.
As to the spring sizes, The smallest dia coil overs use a 1.9" spring, so the hardest available spring for them is 400lb, which should be more than enough, the heavyset spring I've raced a VW on is 300lb at 2 1/4" dia, but I lowered the car with 13" wheels x 22" tyre to maintain good shock travel, a big part of the problem is running big dia tyres and wheels and then trying to run the car low, bottoming the suspension, a race car may use short shocks successfully, but a heavy street car will suffer, stock 944 shocks for instance are longer then Bug ones, the Real solution long term is to re locate and move the shock or coil over to the top of the a arm with a new and higher positioned internal upper mounting to the roll cage, my race car so equipped, now bottoms the trailing arm bolts on the old shock towers and it's still too high! Looks like the shock towers have to go, what tyre height are you running?

[westypoo]

Wheels are 17in and rear tires are 235/45/17. I've run my 550lb Springs and seems good. Basically a shock that red 9 used for the rear looks from pics it's the same Dia. spring as a rear motorcycle shock.

[Dale M.]

Stock shock mounts were never designed to take strain/energy requied for coil over suspension... Period...

Not sold on Atom spring plates.... He seem to be trying to rewrite laws of physics and geometry with his claims...

Dale

[westypoo]

I have a kafer bar Btw.

[modernbeat]

i dont really understand what or how these camber things work.....

They supplement the interior pivot point and take a lot of fab to install on an IRS chassis. The slot goes up and down. Moving the pivot point down adds negative camber. A variation is popular with 911 based racecars.