Quote:
Originally Posted by wi54545
I have been dumping a lot of money into my 1982 911SC. I have owned it since 2015 and have been slowly refreshing it. It was bone stock, previously owned by Klaus Selbert from St. Louis and Lindbergh Motorsports. Last year I removed the CIS injection, added PMO 46 carbs (will go to 3.2ss when that time comes, head studs still hanging in there). Removed all the AC and backdated the heat. SSI exchangers into an old M&K 2 in 2 out exhaust. Went to a 123 ignition setup for carbs with Porsche CDI. New Sheridan complete tinwear and shroud. I've taken quite a bit of weight out of the rear of the car. It runs pretty well (way better than it did) and sounds amazing. I love it.
Now to the suspension. It is all pretty stock (added turbo tie rods a couple years ago) and 40+ years old. The rear torsion bar bushings look smooshed. I've been wanting KW Variant 3 for a while and finally ordered them on 1/1/25. I just received them. That took 2 months. So, I'm thinking that I would like to add Eibach Anti roll bars front and rear. What would you guys recommend for torsion bars? Spring plates (will buy new and shiny)? I need a bumpsteer kit as well as I have the 19mm raised spindles on the KW's. Front bushings? Rebel Racing?
The goal is to have a precise handling street car that I can take on an HPDE once per year. I don't drive a lot, roads can be a bit rough in Western Wisconsin. Wife comfort is not a factor, she has our G87 BMW M2 for that.
Any recommendations? Advice?
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What wheels and tires are you running?
Is the existing body roll objectionable to you?
What ride height are you planning on?
Do you want to increase, decrease or leave the over/under steer character of the car as is?
In general increasing suspension stiffness decreases mechanical grip but at the same time reduces the loss of mechanical grip due to roll geometry changes.
increasing front spring more than rear reduces over steer and vice versa.
When the car is lowered in front 3 things happen
1) shock travel in bump is reduced, at the extreme the shock is riding on the bump stops
2) roll geometry is adversely affected, this adversely affects roll rate and suspension settings
3) bump steer is increased, bump steer aka roll steer can never be eliminated just reduced to a level that the driver can live w/
raising the spindles 19mm as in your KWs addresses the first 2 issues, the low end of stock front is 108+5mm = 113mm, so w/ your KWs a ride height of 132mm returns items 1 & 2 in effect back to stock
when the spindle is raised the outer end of the tie rod is also raised, this counters some of the effect on item 3, at 130mm +/- no rack spacer is needed w/ 19mm raised spindles as the raised outer end matches the amount that the steering rack drops from lowering
if the car is further lowered, again, bump travel is reduced and the difference in steering arm end heights are increased, go down another 11.5mm and now the steering rack needs to be raised by 11.5mm to match, 11.5 is about the max for steering rack rise w/ spacers.
continue to further drop the chassis and eventually the adjustable height steering knuckles become necessary
