Sway Bar / Torsion Bar setup for dedicated track use
 

The car is a '72 911 weighing in at 2250 lbs with roll cage. Motor is a 2.4E equivalent that will be replaced with something bigger (likely a 3.6). I only drive the car at DE events -- havne't even considered club racing at this point. The car rides to all track events on a trailer.

I've asked around at a few other places and had a number of different answers with regards to sway bar and torsion bar sizes. I think I'm settling on 22mm front and 31mm rear hollow torsion bars matched to No. 27 (is that equiv. to a 27mm?) front and rear smart racing sway bars. I'm also addressing all the other parts - poly-bronze bushings, monoballs, etc.

What t-bars and s-bars do you run on your dedicated, semi-lightweight track car?

That sounds pretty good. I ran 21/30 with Weltmeister bars, and now run 400/600 springs with (I'm pretty sure) 23mm Smart Racing bars.

You have to tells us your wheel width and backsets. The further out the center of tread is, the more leverage the wheel has over the suspension. Also, you need to know what that 3.6 weighs so you can balance the car with the right bars.

I'm gonna take a WAG and say 23/31 on 7's and 9's with a later (heavier) motor for all track use. You also have to take in account the track itself. A real smooth track will allow stiffer bars/shocks.

Some of the guys around here just hate it when someone speculates like this. I am using my car as a base line. Lighter motor, 7's all around, 23mm backset. IOW, a narrow car. I have 21/26. I think that will behave similar to 22/30 with the bigger meats and the heavier motor.

Shocks need to be valved accordingly.

My 2100 lb 73 is currently setup with 22/28 with good balance. only requires a slight trimming with the sway bars, as it should be.

For the heavier 3.6 setup, I'd go 22/29 for most tracks. If you will be running smooth tracks with a lot of high speed sweepers, I'd go 23/31.

Not sure what the comments about No. 27 mean. A hollow 31mm torsion bar is not equivelant to a solid 27. The convention for hollow bars is to label with the size of the equivelant spring rate solid bar. Hence a hollow 31 = solid 31.

Note that Jack's car is a good bit heavier than yours.

I'm considering bumping up to 23/30 or 31 - my car gets down to the bumpstops frequently. I'm postponing my t-bar upgrade until I finish the major surgery, ie 'glass doors, fenders, etc.

IIRC, the 3.6 is only like 75lbs heavier than the 2.x motors.

I have 23 front (solid), 33 hollow rear (sander engineering). I drive to the track. 2350lbs soaking wet (including full gas) plus me. That was with 3.2 and ssi's. Now I have 3.6 vram and headers (hopefully I haven't gained too much weight!)

It is not too rough, and barely any dive and squat when accelerating and braking. 29 rears were way too squishy, allowing massive rubbing on of tire inside fender under cornering acceleration. 33's are very firm, and should be ample for whatever engine you put in.

This is all good stuff. I am currently running 15x6 at all 4 corners with 205 street rubber. But that is changing -- 7x16 and 9x16 with some sticky track rubber (not hoosiers).

I also don't plan to make a final decision until I pull out my current T-bars. I have no clue what's on it now. That might start as soon as this weekend.

Given the weight of the car, I would think the 22/28 set-up would work good.

My 78 SCarrerra is at 2600 lbs and change and I have been happy with the solid 23/29 setup I've been running this year. I also went with Bilstein Sports on all 4 corners and poly bushings up front and neatrix in the rear.

I can't comment on sway's......that will be my project this winter but so far it looks like Smart and Elephant offer some good choices

The use of the car, along with you personal threshold for a harsh ride, will lead you to the best solution. I currently have 22/28mm torsion bars with custom-valved Bilsteins, and 22mm front/22mm rear Weltmeister sways. It is plenty stiff for the street, but too squishy for the track, for my personal taste. I have also been know to lift a wheel with this combo, even when running a meager 2.7 (dyno'd on a dynapack @ 113rwhp). I now have a 3.6 varioram, and I would definitely prefer more rear bar. I also have polyurethane bushings that creak and groan enough to wake the dead. They are binding horribly, causing unpredictable handling. I'll be replacing everything but the sway bars this winter with Elephant polybronze bushings, Elephant's low friction A Arm mount, probably sealed rear monoballs, 23/33 Sander torsion bars, an ERP bump steer kit, and most likely custom-valved RSR struts. This setup will probably be too stiff for most on the street, but everyone's preference is different. The car weighs approximately 2600lbs.

Attached is a pic showing front wheel lift at VIR. This is with the 2.7.

http://forums.pelicanparts.com/uploa...1099075334.jpg

Also, I am running relatively large tires, which will effect things a bit. In the attached picture, I am running 235/255 17" tires. I typically run 235/275 tires. All of the rear stick most likely contributes to my front wheel lifting issue.

You'll like it, I guarantee!

Rob,

Sweet Pic! I can even tell you're looking well ahead toward and past the apex.

Oh yeah, GOT TAPE?