Restoring Suspension - what mods should I consider?
 

‘87 Carrera, torsion bar bushings are totally shot, looks like none of the rubber has been refreshed. I’m going to take it to Elephant Racing—they’re only an hour from where I live.

Question is: If I’m redoing all the basic wear items, are there any other ”low-hanging fruit” things that would make a significant difference I should consider? I bought the car to drive, not to show, so I’m not a purist, but also not planning to track it or looking to do anything extreme. I mostly drive mountain twisties (many are pretty bumpy), coastal highway, around town. Thoughts?

The most obvious and cost effective is lowering the car. this will improve handing as you lower the centre of gravity and you have to pull the torsion bars anyway to reset them for ride height.

beyond that the sky is the limit, stiffer torsion bars, re-valved shocks , upgraded rears. its all about how much money you want to spend.

hard to believe that the torsion bar bushings are bad unless the car has hundreds of thousands of miles and the bushings were never lubricated. Since you are driving it on the roads, I would not change a thing except to make sure that all of the factory suspension and sway bar and strut/shock bushings are good ones and lubricated, the tie rods wheel bearings ball joints and cv axles are in good condition (cvs and wheel bearings well greased) that the tires are high speed rated ones, and that you install four bilstein shocks. With this you will be all set. I would not lower it as it will make the ride even harsher than the old torsion bar suspension makes it now (we are very very spoiled by the new 911s!!)

FWIW, the bushings on my 89 were in really nice shape front and rear after about 90k miles.

What I would do:
refresh with RUBBER the bushings needed - stay away From monoball or polybronze. Good quality rubber is fine, and elephant has good stuff there
Keep the stock torsion sizes, don’t change them.
refresh your sway bar bushings
refresh your sway drop links
new shocks front and rear - bilstein HD or Sports
Turbo tie rods
Elephant bump steer kit
a proper alignment, not too low, with proper rake and camber
GOOD, fresh tires
good pads - i like the porterfield R4S for the street

Make it fresh, a better shock, and the tie rods. Those tie rods were the single biggest improvement i made to steering feel on my 89.

Done.

Yes, there are...

- Tires are critical and so is their width - wider = more stick in corners, but detracts from the light, nimble handling feel of the early 911s; try Front 32/Rear 34 to get rid of some understeer

-get either Elephant rubber bushings (which most prefer) or Polybronze (more road feel; I like these)

- use digressively valved shocks - Bilstein will do that for you and rebuild your old ones, dunno re other brands

- I have hollow torsion bars (less wt.) may not make sense in yours; but set the stiffness where you want for your driving style (mine are like an RS); adjust sway bars to match

^^^ good. to know you had good experience with polybronze. the one I had was kinda noisy and harsh?! Maybe setup bad?

I keep reading about these digressively valved shocks. So, for example, lets say I pickup a new set of rear and front inserts. My car weighs 2200 lbs and has 21/26 torsions. who do I send them do and what do I tell them I want?

Cool, thanks for all the great suggestions. My car does indeed have a little over 200K miles on it, with original suspension, so it makes sense that it's time for a refresh. I think I'm going to go for a straight refresh which includes all the rubber parts, shocks, turbo tie rods, spring plate hardware, ball joint hardware, etc.

Spyerx, what are the effects to driving characteristics of adding bump steer?

it actually removes bump steer. If you lower the car, you change the angle of attack from the steering rack to the wheel hub, this causes a geometry change that causes you to feel a heavier steering wheel and/or when you hit a bump you really feel it in the wheel. The spacers lower the steering rack a bit to help with this. to really fix it fix it with very low cars you have to address with spacers on the tie rods.
I'm sure chuck will want to install them assuming you'll lower the car to say euro height.

You can see some pictures and examples of adjusting bump curves on my 964 thread. That car has zero bump steer, so it's extremely stable and consistent steering under all angles of usable suspension travel. my 997RS is the same way.

you can send them to someone near you with a super secret sauce recipe, who then sends them to Bilstein - or you can send them directly to Bilstein yourself and ask for digressive valving



ThyssenKrupp Bilstein of America Inc.

14102 Stowe Drive

Poway, CA 92064



San Diego

United States Tel.: +1 858-386-5900

Fax.: +1 858-386-5905



also,
Elph. sells digressively valved new shocks

You should corner weight the car after suspension is rebuilt.

You can also get them from Steve Weiner. He may recommend a mix of Sport and HD. That’s my plan if I ever get to the suspension.

Mark

Spyerx, take it you recommend keeping the torsion bars as '87 where increased in size over previous year cars? I have an '84 which I believe are thinner and was contemplating going with larger torsion bars, likely hollow Sanders in 21/27 or 22/28 when I get to my suspension....

BTW, polybronze noisy could be not aligned correctly or not greased (I do it every oil change)

harsh is harder to guess at - they pick up and transmit every tiny bump - so that is either "great road feel" or harshness I guess


polybronze, monoballs (other than the ball joints), stiffer bars, etc. all depend on what you want in terms of sportyness vs. NVH - and that, in turn, is usually set by your age and WAF

when young, you stiffen the torsion bars, lower the car, put on polybronze and buy a loud muffler

when old, you take all those things off and make it all more cushy

when really old, you hotrod your wheel chair