Recommendations on suspension upgrades for street/track setup in 81 SC Targa

[UrQuattro]

Hey all,

I'm wanting to get my suspension upgraded...

So far, everything is stock except the wheels and the sway bars, which are from a later Carrera 3.2. My taste is for a firm ride, and I do not mind dealing with the harshness that comes with stiffer suspension settings. My driving style is quite aggressive, but I also know my limits and how to handle myself, so generally, handling over comfort for me.

My UrQuattro is set up with a stong bias toward the track, and I want to go a little bit milder with the 911. Ultimately, once i get it set up, I will be doing driving events in groups 3 and 4 (the most advanced group) with NASA. As I've mentioned before, I used to race in NASA and got a LOT of track time in my quattro and in the race car. I know, though, that the 911 is a COMPLETELY different beast, and so i'll spend a lot of time re-learning how to drive on the track, and re-refining my skills.

On the public highways/byways/and canyon roadways, I would like to have very tight control of the movements of the body on the suspension. For example, if i am driving down the highway, and i jiggle the steering wheel back and forth, i'd like to feel minimal to no roll, and as much elimination (im gonna try to describe this as best as I can) of that extra movement of the rear end that gives you that somewhat unsettling feeling. It feels like even though the front suspension has settled, there is still excessive roll, or movement behind me in the driver's seat. This might be able to be addressed by shoeing the car with tires with very stiff sidewalls, as my UrQ does this now even though it didn't before... It started doing it when i switched from yoko A520's to the AVS ES100's. The A520's had VERY STIFF sidewalls (i remember trying to compress the sidewalls with my hands and not having too much luck), but the ES100's, even though they grip really well in the turns once they take a set, their sidewalls are MUSH...

I don't mind feeling the texture of the road - I want to feel very connected to the car and it's interaction with the road. I know that the best way to get this is to install a race car level suspension, but that isn't practical for the street, and it will be murder on the chassis...

So...

I have a friend that is selling me a set of front monoballs for the upper strut mount. He modified them to allow more camber adjustment. I'm also getting a triangulating front strut brace from him as well. I have a set of turbo tie-rods to install as well. Also, i will be installing a brey-krause harness bar - the one that triangulates down to the center tunnel where it attaches to the seatbelt latch attachment point. Also i'll be getting those targa down bars. I don't think they can be attached at the same time, but maybe i'll have them welded together to get some really nice stiffness going on in the chassis in order to handle the stiffer suspension.

I am very lucky in that the car has bilstein struts and shocks from the factory, so there are more options open to me than there would be otherwise.

I'll probably do this in stages, as i know that this gets expensive so quick that i probably already owe money to someone for simply thinking about a full suspension overhaul. To that person, i swear, I get paid tomorrow.

So, my first stage is new torsion bars and new bilstein inserts and shocks, along with the installation of the parts that I have already noted as having in my possession. My wheels are 3 piece 16 x 7/8 with stock size tires. So, what would you all recommend as torsion bar sizes and bilstein choices. My VERY knowledgeable friend recommends 22/28 with bilstein HD up front and sports in the rear.

What are your opinions regarding this setup? Will it be too stiff? Not stiff enough? Unbalanced? Should i be looking at something a little stiffer in the rear given the little bit of extra weight of the targa? maybe a 29mm?

Eventually, I'll probably end up raising the spindles, install monoballs in the rear, polybronze all around, adjustable sway bars, Alton's 17" fuchs, spherical tie-rod ends/or bump-steer ends, etc...

So, I know that this is a really long post, but i figured that you needed to know about me and my preferences and such before you could give an informed opinion of what i should go with... I really appreciate your time, and thank you very much for all of the info that you will be able to help me out with...

Michael

[Flieger]

You don't have to grease these and there is no Polyurethane to squish.

Suspension1

[JeremyD]

I had 22/30 in my cabriolet - Monoballs up front - poly bronze a-arm - turbo tie rods with bilstein HD all around. - poly bronze and sway away adjustable plates in the rear.

It was still firm but not bouncy. probably should have gone with sport in the rear - but it was a cabriolet.

Handled very well at the track. Has a little more stiffness in the rear than many like - but I would rather have a little more oversteer than push.

I like what I see with the rebelracing A-arm bearings -

My new car - has 22/28 with Koni adjustables - it's alot lighter but is a little bouncy too.

The other thing you might consider is sending your spindles off to get raised, especially if you move to 17" wheels.

[UrQuattro]

Thanks for wading through my post and replying. Youre right, those bearings look fantastic.

I'm thinking I might go with a 22/29 setup with HD/sports.

On my urq, I have koni inserts, and no matter what I did, the ride was bouncy on the highway and such. I'm wondering if it's the konis?

Michael

I had no idea my post was as long as it is. Sorry.

[Head416]

First off, I'm no suspension expert. But, I've usually seen people recommend 22/28 or 23/29.

I think that 22/29 will have more of "that extra movement of the rear" you don't like than 22/28 or 23/29. Stiffer rear = more oversteer, stiffer front = more understeer. How much difference does 1mm make? I have no idea. But since you seem to dislike oversteer, I would think you would want to minimize oversteer more so than what people normally do. Like 23/28, or something like that. (But don't take my advice, I'm just trying to get the conversation started.)

Can somebody with more experience than me chime in? Am I right on this? Or am I mixed up?

[Flieger]

stiffer rear does mean more oversteer. stiffness increases with the 4th power of the diameter, though, so you will be increasing the rear diameter more millimeters than the front to maintain the same front/rear balance of roll stiffness.

[UrQuattro]

I don't dislike oversteer... I was worried about that coming across incorrectly when i talked about jiggling the steering wheel on the highway while going straight... im just VERY sensitive to chassis movement, and that extra little bit of 'squishyness' isnt from suspension now that i think about it more... it has to be the tires because of my experience with the UrQ.. I had that set up very loose... it's tough to get an UrQ to be loose, but it will do throttle-on-oversteer if i ask it to.. it will drift perfectly with a slight bias toward leaving the rear end out a little bit.

I apologize for giving the impression that i want to increase understeer... i HAAAATE understeer... it scares me... I want to have a neutral 911... well, as neutral as is possible... Minimal understeer entering the corner as i go for the apex, and neutrality as i hit it, roll on the throttle and power out of the turn with the pedal down..

That's why im thinking that a 22/29 might be better than 22/28.. i've read a few stories about people having issues dialing out the understeer on a 22/28 setup, and i'd rather have to go the other way... Dialing out oversteer is more fun than the alternative IMO...

I found a post online that had a conversion chart for front and rear torsion bars... i'll try to find it again.

Michael