mismatched torsion bars

[raceman]

here`s the deal;l did a trade with the local high performance alignment shop and l was to get installed on my 84 Carrera 22mm front t/bars,28 rear,adjustable spring plates ,and all new bushings throughout.Everything turned out great,l`d already done the turbo ties,bilstein sports,bump steer etc.What l found out however was that the rear t/bars are 27mm , not the 28mm l`d asked for.So l`m running 22/27 wich seems to me unbalanced,the car pushes a lot.l was thinking to upgrade the rear sway bar but isn`t that a bandaid? l`ve lightened the car with the usual glass and carbon fiber and with the t/bars as is it`s pretty stiff which is fine butl`m thinking to switch out the front t/bar to a 21mm for better balance.Either that or have him put bigger out back...any thoughts on this?thanks in advance.....

[Wil Ferch]

Its true that the balance you now have brings you closer to more understeer ( compared to usual 21/27 or 22/28). I've gone as far to recommend 21/28 ( or even 29)...or 22 /29 ( or even 30) to help dial out some unwanted, lower speed undesteer.

Having said that...I don't think you are OT. You can dial out some of the understeer with slightly stiffer rear anti-roll bar settings...but however you intend to tackle this , a word of caution. Make sure the "understeer" you're trying to correct is low speed ( high steering angle, small turn radius) understeer....and NOT high speed ( low steering angle, large bend radius) understeer. Why? If you get the car balanced on low speed turns, it might end up diabolically unstable ( oversteering !) on high speed sweepers. The tendency with any set up you have is to get less understeer when the steering angle is less.

High pucker factor....fast but dangerous..

Another point...driving style on low speed turns has a lot to do with the degree of understeering you have. If you power-on too soon, you'll have grinding understeer vs. carrying a bit more speed in to the turn, etc..

---Wil

[Zeke]

That about covers it frome what I know.

If you asked for 28's why didn't you get 28's? I think i would want what I asked for, especially since it's the recommended setup.

I'm using 21/26 beacuse of a lighter car and narrower track. Which brings me aroudnto your car. What rear wheesl. The wider the track, the more bar you need to keep the same rate.

[raceman]

thanks Will,good points to remember.l haven`t really had too much time to track the car with the current set up and as for high speed tests l haven`t done that yet either.Low speed turn-in is poor,worse then before the mods possibly.The car has fiberglass front fenders/bumper,no spare carried,glass rear bumper and tail..l may go 21mm up front and adjustable sways to fine tune..

[raceman]

Wheels/tires? good question.l`ve got factory 17" 993 cups,7" and 9" using 3/4 spacers up front,1.5" in the rear.Tires? l`ve got the 205/50 front,255/40 rear..

[Wil Ferch]

205 front with 255 rear is a real bear for low speed understeer..all else being equal.

225 fr / 255 rear.....or 205 fr / 225 rear would ( from this perspective) yield a better fr/rr balance.

---Wil