dbryant61

I am preparing to do my suspension again, and am writing to ask those on these lists for advice on t-bars and anti-roll (sway) bars. I did this two winters ago with 22 & 28 torsion bars and Weltmeister 22mm anti-roll bars (which will be for sale when I am done). The purpose of this step is to make the car full race to run in PCA G-class, NASA GTS, and possibly SCCA ITS. Once I decide on bar sizes, I will be sending the struts and inserts to Bilstein for custom re-valving.

I am pretty sure that 23mm front torsion bars are the standard, but would 24 be better?

As far as rear torsion bars, I have heard everything from 30 to 33. I really do not know where to go here.

Finally, anti-roll bars. It seems that Tarrett and Kokeln sway bars are hollow equivalents (same torsion rate) of the Weltmeisters. However, the Smart Racing bars are available much thicker. I really need your help here.

I realize that I could just go with the Smart Racing track setup (23/32 t-bars, 31F 27R ARBs), but this setup is listed for a wide range of vehicles, showing no differences for weight or power.

Thanks in advance for your advice.

Don Bryant

BrianKeithSmith

I don't have much to offer Don, just wanted to say Good Luck! with you upgrade! Have fun, be careful!

Larry Herman

Having run a Carrera with 23/31 T-bars and 22/19 Sway Bars I would run the biggest T-bars I could get if I were to build another. I know that there is info out there on what exactly the spring rate is of T-bars on the 911. They are surprisingly soft IIRC.

As an aside, I had my Bilstien sports revalved by the factory to match, and it came out great.

Alan Herod

I am using 23/33 Sanders (drilled/hollow/ or whatever you call it) in the SC. Double adjustable shocks with more rebound and Smart Racing Adjustable sways. A well known pro did not like the 23 and recommended I switch back to the 21mm. I tried the 21s for two events through a range of sway and shock settings and went back to the 23 baseline to try and home in on the solution. The rear rebound is really crucial to threshold braking in areas like the back straight at VIR and Mid Ohio. With stock Billstein Sports the car moved around quite a bit under hard braking. I have only just begun to understand the effect of more/less compression/rebound. I have read the Puhn book more then a few times and would like to find more information. If anyone has a recommendation on reading material on shock set-up, it would be really helpful.

Larry Herman

I'm not surprised. My Carrera felt soft in the front even with the 23s.

The caveat with having a pro setup your car is that you must like the way they drive and how they expect the car to handle. Otherwise, they will be setting it up for themselves, and you will not feel comfortable in it.

chrisp

I'll throw out a baseline for consideration for a D class SC (used to be G class).

Torsion bars: 23F/31R
Sway Bars: 31F/27R Smart Racing
Shocks: Bilstein valved to match (this can be shop dependent and does effect ultimate performance greatly)
Bushings: All bearing or solid bushing

Although nice, canister shocks are probably not necessary to run with the big dogs (which I'm not)

dbryant61

Brian, thanks for the support.
Larry, Did you feel your sway bars were sufficent? I may try the 24mm front t-bars and whatever the thickest rears are and not change sways if that will work.
Alan and Chris, thanks for the input.

Don

Astroman

Is there a difference in the factory revalve vs SRP's revalve?? Which do you all recommend??

Larry Herman

Don, if it were me I would install the 24s & the 33s and see how it feels. I would then evaluate a sway bar change in light of the balance of the car. My old car understeered somewhat, but back then they really didn't make a decent rear sway bar, so I stayed with a factory style 19mm bar that I found, with a 22mm weltmiester front.

Larry Herman

I do not know anything about the job that SRP does, but based upon reputation, it should be good. Because it is an art as much as a science, you would get 2 differently valved setups, and it is difficult to know which would be better. The 3 way Motons on my car are incredible. Knowing how well I can dial them in, personally I would go with the least expensive decent quality 2 way shocks over anything fixed.

Gary R.

Dan Jacobs uses 31/23 , SRP sways, custom valved Bilsteins, and his "secret sauce" alignment to produce consistent podium G (now D!) class cars. My 930 has 33/24 Saunders hollow bars with all the other SRP stuff (may be heavier sways) and it's perfect to me also.. Make it simple, get a pen and paper, the telephone, and call him. Then you to can drive a CT Stock car! LOL

dbryant61

Larry and Gary,

Thank you very much for your input. Larry, I get what you are recommending: the carwill benefit from the stiffest "spring" I can find, and then use to sway bars I have to tune over-/under-steer. These suspensions are so far away from the 1400 lbs/in springs they run on the Cup cars.

At the risk of being convicted of blasphemy, I have heard that a few G-class cars that came out of that Hairy grrrage have questionable parts allowing 3.0 deg of negative camber. Anyone care to confirm? The best I can get is 2.0, the car is very low, but all holes and ball joints are in their original locations.

Don

Gary R.

I can say (as I built my last two cars) that we use stock ball joints and do not change/enlargen any holes nor use adjustable camber plates.

Larry Herman

I don't know about what Dan uses, but I got -2.5 degrees out of my car by moving the struts to their innermost factory position, and then tightening the strut brace to suck the fenders together. There was very little fender gap when I was done.

Jarez Mifkin

how much camber are you guys getting in the rear?