suspension reccomendation

[jsfried18]

Hey Guys im getting ready to refresh the suspension on my 87 911. Its just a weekend car and will be doing a lot of autocross and track events with it. I want to retain the current torsion bars for the time being and possibly upgrade in the future.

Going to do tarett sway bars front and rear. I want to know if i should go for hd bushing or poly bronze bushings and which Bilstein shocks are recommended. I've seen some people have done different shocks from and rear.

Any advise is much appreciated.

[Bill Verburg]

Originally Posted by jsfried18

Hey Guys im getting ready to refresh the suspension on my 87 911. Its just a weekend car and will be doing a lot of autocross and track events with it. I want to retain the current torsion bars for the time being and possibly upgrade in the future.

Going to do tarett sway bars front and rear. I want to know if i should go for hd bushing or poly bronze bushings and which Bilstein shocks are recommended. I've seen some people have done different shocks from and rear.

Any advise is much appreciated.

Some considerations are;
budget
how racy you want it to be when using it on the street or how streety you want it to be when on a track
how do you want to affect balance, more over steer, which tends to be what A/X wants or less over steer which is what tracks want
grip levels of the wheels and tires

It's far better to get the main part of the suspension right than to tweek a stock one w/ sways and preferable to get the wheel/tire package first



for stockish wheel and tires sets, biased ~50/50 street track keeping bias close to stock 21/27 t- w/ stock sways to start, then add an adjustable front sway if needed

Bilstein B8 hd front and B8 sport rear shocks would work well, but adding a custom digressive valve stack takes a lot of the sting out of street use and adds to the track competence

you are going to be limited by wheels and tires, 7 & 8 up to 8 & 9.5 w/ 205/50 to 225/40 fronts and 225/45 to 255/40 rears are very desirable

use sport rubber bushes unless you don't mind the extra maintenance and harshness of poly bronze

[AlistairWallace]

Reach out to Elephant racing for advice. They are expensive, but they deliver. I assume if you are going to race, you will wish to lower. If you plan on lowering. Make sure your front shocks include the double tie rod support (upper and Lower). Like below.


I run torsion bars with no issues, they work fine, but adjustability is miserable.

I run the KW V3, so cannot comment on the bilstein. Im happy (expect they don't come with the double support, you will need that added).

Buy the needed bump steer parts up front, you will need it.

If I had to do it over I would buy the GT3 kit and the ASP spring plates

[jsfried18]

Appreciate the insight. Big question for me is how harsh are poly bronze bushings.

I’m currently running 7” and 8” wheels on re71r’s

[jpnovak]

Poly bronze are not harsh. In fact, they are so compliant they feel soft.

[Otter74]

My car has polybronze bushings and monoballs on it (done by the PO), stock TBs. They give more impact harshness than stock bushings for sure, but I find them very livable for street use, including Chicago city streets. You may find this less appealing with higher-rate TBs. And of course they require regular lubing. Ride quality on bad streets is better than my Saab SPG was before I put stock springs back on it.

[Bill Verburg]

Originally Posted by jsfried18

Appreciate the insight. Big question for me is how harsh are poly bronze bushings.

I’m currently running 7” and 8” wheels on re71r’s

That's a very nice setup, One of my track sets is RE71, very nice for a street tire.

But w/ 7 & 8 x16 205/50 & 225/45 A052s would be even nicer

The above would work well w/ the suspension I outlined above

anecdotally my track car is all mono-ball and set up as described above but w/ much higher wheel rates and is stretable as long as the roads are smooth, get into a lot of potholes and frost heaves and things go downhill quickly

[jsfried18]

Thinking about starting with rennline hd bushings and see what’s what due to cost and not dealing with the maintenance. I also live in Chicago so may benefit from a softer bushing

[jsfried18]

What’s the reason I keep seeing people say only do sport shocks in the rear and greens up front?

[Bill Verburg]

Originally Posted by jsfried18

What’s the reason I keep seeing people say only do sport shocks in the rear and greens up front?

weight on the front is only 525# perwheel w/ t-bars that impart a wheel rate of 107ln/in, the Bilstein shock specs in front are 130/76 sport is 160/161 the hd better matches the pairing
in back there is ~800# perwheel, 25mm t-bar has a wheel rate of 149 lb/in the hd sp[ec is 195/151 and sport is 220/180 here the sport is the better match for the pairing

The shock specs are at ~20 ips and are in N, first # is compression second is rebound

[jsfried18]

Well HD’s up front and sports in the rear it is! Last question, Are the decambered ball joints worth the up charge vs the oe style ones?

[jac1976]

I would use the search feature before spending any money. Jamie and Bill, among others, will help direct you in a stepwise fashion. Reread Bill’s first reply. Adding big name sway bars to a stock setup may not be the way to start. Speaking as someone who has stockpiled an inordinate amount of parts, I ultimately rely on the experiential advice of these guys and a few others when it comes to which parts to install with respect to my particular car setup, intended driving environment and personal skill. Everything must be in concert. Obviously, my advice is not technical, but rather referential. The only additional advice I would offer is to drive the car as much as possible to figure out what it lacks or what you want or need.

[Showdown]

I couldn’t imagine going with a stiffer than stock setup on my car in Chicago, but then again I daily mine so maybe I’m just deep into the crap streets.

[Otter74]

Originally Posted by Showdown

I couldn’t imagine going with a stiffer than stock setup on my car in Chicago, but then again I daily mine so maybe I’m just deep into the crap streets.

I’d offer you a ride in mine, but it’s sick so I can’t do that until it’s well again, but once it is you’re welcome to. I live in Avondale.

Originally Posted by jsfried18

Thinking about starting with rennline hd bushings and see what’s what due to cost and not dealing with the maintenance. I also live in Chicago so may benefit from a softer bushing

I’m curious what your car looks like, since I do occasionally see other 911s around the north side.

[Mark Salvetti]

Since you will have easy access to the torsion bars when you do the bushings, it is the perfect time to upgrade to something like 21/27 front/rear. You don't need to jump to expensive hollow Sanders bars - I bet you would be hard-pressed to tell the difference between them and used SwayAways.

The bushings and realignment will cost you more than the torsion bars. Do it now when you have things apart.

Mark

[HarryD]

Don't know where you are but some quality time with a Porsche Specific race shop is invaluable in determining what setup to use for your needs.

I am fortunate that Steve Weiner and Rothsport Road and Race is local to me and they were able to advise me on what I needed plus perform the final suspension setup (lower, corner balance, align).

[Cory M]

I'm a big fan of the Tarett bars and have installed them on several cars. But I agree with the others here, you are better off doing torsion bars first, especially if you already have it apart for bushings. For track and autocross 21/27 is still extremely soft, I'd look into 21-23 front and 29-31 rear. The bushings are the least bang for the buck and work required, unless yours are shot now.

[HarryD]

Originally Posted by Cory M

I'm a big fan of the Tarett bars and have installed them on several cars. But I agree with the others here, you are better off doing torsion bars first, especially if you already have it apart for bushings. For track and autocross 21/27 is still extremely soft, I'd look into 21-23 front and 29-31 rear. The bushings are the least bang for the buck and work required, unless yours are shot now.

It all depends on what the OP wants. It seems he is seeking a dual purpose car.

My 1973.5 with 174,000 miles has a mostly stock suspension. A few upgrades were done a few years ago. I drive on the street for fun, autocross 5-8 times, and about 6 HPDE's a year.

My suspension has turbo torsion bars (21 mm front/26 mm rear).
Front and rear 19 mm adjustable sway bars.
I replaced my rear spring plates bushes with Neatrix parts. All other bushes are stock and original.
Bilstein HD fronts and Sport rears.
For the street I use 16x6 Fuchs with 205/55-16 Continental Extreme Contact Sport as tires and auto cross on 15x6 cookie cutters with Hoosier SM’s 205/50-15 tires.

I had Rothsport lower/corner balance/align the car and apply his "secret sauce". Car rides and handles great.

FWIW. My wife prefers the 911 ride to my totally stock BMW Z4.

[jsfried18]

my main reason for wanting to do bushings is because the car apparels to have about 200k miles and no signs of them being replaced

[Marko888]

I have a Rennsport Systems setup for an ‘87 Carrera. Bought from Steve and never installed. 21/28 Sanders bars, custom valved Bilstein Inserts and Sport rear shocks. All brand new. PM if interested. It was intended for mostly street, occasional track day use. Ended up going a different direction altogether, so never even installed them. I also have some new (never installed) Rebel Racing control arm bushings.