Buck3eighty

I drive an 84 4000Q. The guy I bought the car from installed Koni shocks with stock springs, and a Blaufegnugen(spelling?) rear sway bar, as well as Delrin front control arm bushings.

I am planning on installing a coilover-type Ground Control suspension to replace the factory springs. The car is driven on the street, but will be going to RallyCross and AutoCross events.

I would like to remove the sway bars(front & rear), to promote the independence of the suspension and get rid of that pesky "clunk" from the rear sway bar.

Does anyone have any suggestions regarding spring length and rate for such a setup? I'm looking for a setup that will make the car easier to "rotate" and reduce understeer as much as possible.

Also...does anyone have an idea for 4-wheel alignment specifications? Something good for competitive events, but still acceptable on the street.

eharleq

You picked the right car. I have a very similkar setup and have learned the hard way how to set it up.

The car understeers, period. It has too much mass over the front axle. The only way to solve this is to drop in a 1.8T. You can make the back end heavier (which I do not advise) or you can make the rear spring rate so high that the car is undrivable (and it will just snap from oversteer to understeer).

I don't have much understeer with these changes, none with the rear bar on. A touch of understeer is much safer and often faster. You can then provoke oversteer if you need it. Don't forget that as you go faster, you get more oversteer: go neutral at your top speed and work backwards.
Also, when you lock the diffs you will get MUCH more understeer.

Move the battery to the right trunk. Get a plastic radiator tank or all aluminum (preferred bu way spendy). Throw away the vacuum pump, seal off the hole. Throw away the air conditioner.

I run 340F/250R with a rear bar (street/disconnected off-road) Koni adj. struts. I also use full-length celasto bumpstops. If you don't use them add 100-150lb/in per end. The celasto gives a rising rate at the end of the strut travel. I bottom out on jumps only.

Many people feel (wrongly) that you slam big springs on and go. Springs do NOTHING for roll. Roll is not as bad for handling as some perceive, but it still has to be controlled. The people who run stiffer springs than I do on this car who actually know what they are doing, are soley trying not to destroy the struts in big yumps or drive on perfectly smooth tracks. They also spend tens of thousands in prep and have custom built a-arms, etc.

You want the spring that is just stiff enough give you traction and won't bottom out more than 1-2x. Then you want some small bars to control roll.

The art of chassis balance is that you only give the suspension enough spring to match the weight of that end.

Give the car as much suspension travel as you can find. You do this with raised strut tops (metal or blue audi), and if that is not enough, shorter strut shafts.