Need Advice - 23mm Front T bars ... - Page 2

jpachard · 02-20-2003, 07:05 AM

Yes, The later cars are a bit stiffer( I have a full cage welded into my '87 and it's really stiff now) as compared to the earlier cars. As a rule, you should always set up a track car to push slightly in slower corners. I don't know what the AutoX guys like though.

Cheers, James

Superman · 02-20-2003, 10:22 AM

I also agree with Randy, Doug and Jack. And with Warren and JW. Listening to those guys is smart.

What I am hearing here continues to reinforce my feeling that the rear is where I need additional stiffness the most. When the time comes, I think a 22/30 combination might even be good. I have not tracked yet, though I am anxious to do so. I have autocrossed though, and have nothing good to say about trying to autocross a car that won't rotate. VERY frustrating.

I am not a bit sway bar fan, though adjustable ones would be good. I CERTAINLY am not considering stiffer front sways. I'm more tempted to just remove the front sway bar. Funny, but I kinda prefer racing with FOUR wheels on the track.

I am more scared of overstiff shocks than overstiff torsion bars. I think that if my daily driver/weekend warrior ends up causing dental damage, it will be the fault of the Bilstein Sports.

Randy, you're hard-core. See you Saturday.

Wil Ferch · 02-21-2003, 05:28 AM

Craig Watkin's point about possibly crossing over the bending limit of the front A-arms, may have some merit. Consider the following "equivalent" spring rates I worked up for the front of our cars:
-- 18.8 mm= 110 lb/in
-- 21 mm = 173 lb/in
-- 22 mm = 210 lb/in
-- 23 mm = 250 lb/in

The 23 is over 2 1/2 times as stiff as typical "stock"...

--Wil Ferch

jpachard · 06:35 AM

Quote:

Originally posted by Superman

I am more scared of overstiff shocks than overstiff torsion bars. I think that if my daily driver/weekend warrior ends up causing dental damage, it will be the fault of the Bilstein Sports.

.

I agree completely. If you install a Bilstien damper, it MUST be correctly valved to the chosen spring rate. Otherwise you will get all kinds of funky things going on in regard to your suspension.

Cheers, James

tobluforu · tobluforu's Garage

I went to 28 rears, stock front. Then after fiddling like crazy with it, I went to 21 fronts. Fiddled again. Then went to 29 rears. Fiddled and found it to be just about right. I then added sway bars. Found out for my car that rear swaybar(welt) worked best at 1.5 inches from end of bar. Front w\droplinks set half an inch from end. Both 22mm. I have hardley any low speed push. But, my car feels light in the front at speeds when cornering. I'm now thinking of raising the front-any ideas there???

Wil Ferch · 02-21-2003, 07:57 AM

Tobluforu:
If you ended up with 21 front / 29 rear...you're at a point where you're a "tad" too stiff in the rear ( relative to common 21/27 practice...or even the 21/28 upgrade that takes out a bit of low speed understeer)..and you're now finr tuning with anti-roll bars.
remember....set your self up for neutral on "high" speed turns ( low steering angle)...because high steering angle/low speed corners will almost always promote an amount of understeer that you'll never dial out ( or if you do..makes the car diabolical on high speed sweepers with tail-out oversteer!). You may want to dial back some low speed push that you counter-act with technique...not set up.
---Wil Ferch

Randy W · Randy W's Garage

As Will noted, I think most low speed push can be corrected by altering your braking style. A 911 that is neutral in high speed corners is much less taxing to drive and more confidence inspiring. My personal opinion is that 21/29 is OK if you have lots of engine back there (3.2 or 3.6).

As far as the front end feeling light at speed - if you already have an S or RS front spoiler, raising the front probably won't help. A "floaty" feeling is often shock related - what spoilers and shocks are you running tobluforu?

Wil Ferch · 02-21-2003, 10:28 AM

Tobluforu:
Help us confirm...light front end always when "at speed"?..or only at high speed "when cornering"?
If during cornering, then I'll stand by my previous post...otherwise RandyW is correct and you must look for other things..
---Wil Ferch

RoninLB · 02-21-2003, 10:51 AM

Quote:

Originally posted by jpachard
If you install a Bilstien damper, it MUST be correctly valved to the chosen spring rate. Otherwise you will get all kinds of funky things going on in regard to your suspension.

Cheers, James

so.. if the Bilstien is used with 21/27 springs they most definately should be re-valved.. OK.. how radical will be the change in re-valving?? on a street/DE 911

jpachard · 02-21-2003, 11:09 AM

Ronin, That question should be directed at Bilstien. My mechanic/suspension guru just sent mine off to be re-valved. I can check with him to see what he recommends if you like. What size are your torsion bars and how heavy is the car etc.

Cheers, James

RoninLB · 02-21-2003, 11:25 AM

Quote:

Originally posted by jpachard
Ronin, That question should be directed at Bilstien. My mechanic/suspension guru just sent mine off to be re-valved. I can check with him to see what he recommends if you like. What size are your torsion bars and how heavy is the car etc.

Cheers, James

thanks for your time James.. I got the 21/27 springs, Welt spring bushings ft/r, stock ft/r sway bars, S-03s.. and big oversteer.. the car is stock weight +100lbs.. the ride height at the fenders is 25 1/2 ft and 25/r... kinda stock alignment.. I was going to try the '88 911 stock front sway bar, 22mm/I think.. I have a SC ft sway bar 20mm/I think.. but want to do the bigger bar.. oversteer/big time.. the rake is 1deg and decent corner balance..

jpachard · 02-21-2003, 11:28 AM

Ronin, Do you participate in any of the CVR DE's? Do you take your car anywhere for work? I see your local, maybe we have seen each other at an event? I will copy the thread you posted and e-mail it to my mechanic and see what the prognosis is.

Cheers, James

RoninLB · 02-21-2003, 11:36 AM

Quote:

Originally posted by jpachard
Ronin, Do you participate in any of the CVR DE's? Do you take your car anywhere for work? I see your local, maybe we have seen each other at an event? I will copy the thread you posted and e-mail it to my mechanic and see what the prognosis is.

Cheers, James

I'm with Metro NY PCA.. I do a DE to see what I'm dealing with.. or to certify an engine re-build, LOL.. I'm more of a cross country go-cart driver.. I do everything my self. even put a low-rise lift in my home garage. and hang with a couple of 911 shops on Long Island... thanks again

Superman · 02-21-2003, 11:36 AM

Randy, I can see now that in order to be competitive I will need to learn to use my brakes in turning. So, I will be looking to ride with some of you instructors, to watch feet. That's my goal this year. Learn to use my brakes. At one point last year, I noticed an ENORMOUS amout of front traction under heavy braking. Without this skill, my turnaround rhythm is sluggish to say the least. I heard Greg Fordahl has six legs and ten feet.

vesnyder · vesnyder's Garage

You guys have been a tremendous help, and helped me avoid saving a few bucks and ending up with a bad setup. I will pass on the 23mm t-bars and go with 21 or 22 (still undecided)

Tinker · 02-21-2003, 03:24 PM

Ronin,

... kinda stock alignment.

Maybe you need a professional to fine tune it. Alignment and corner balance can make a big difference with a knowledgeable tech.

Tinker

89911 · 02-21-2003, 03:36 PM

Wil, do you still have that program for setting rear spring plates in relation to torsion bar size, car weight and height? It was usefull when I did my change. Thanks.

RoninLB · 02-21-2003, 04:17 PM

Quote:

Originally posted by Tinker
Ronin,

... kinda stock alignment.

Maybe you need a professional to fine tune it. Tinker

I understand your point.. stock camber ft/r kinda dials in some understeer.. thus more camber in rear..
my camber is 0/ft and maybe -1/rear. which is more rear than stock.. and if greater tire psi difference ft/r increases understeer, I think I'm maxed out with 29/ft and 35/r on a set of 205/16 sneakers all around.. the alignment was confirmed, so it's correct for what I'm doing

WFerch · 02-21-2003, 04:56 PM

8991:
Yes...the simplest path to the Ferch Method (tm) ..

....of rear spring plate angle determination is:
http://www.vintagebus.com/porsche/index.html

--Wil Ferch

tobluforu · tobluforu's Garage

Back from vaca. My car feels light at high speed w\bump steer based on the car being so damn low. Running over 2 degrees of negative camber front and rear. 2.6 rear. 2.0 front. I'm thinking it's my front shocks. I run Koni adjustable in the rear set at full stiff. They use to be a full soft. What a change that made in the sense of pitching the car sideways-to stiff I feel. The fronts are Boge. Why because I was once told that I should go softer in the front. Should I go back to koni adjustables in the front? There just sitting in my garage. I also Have a rs's' front spoiler. Thanks all..