Gotta new(ish) 996 and I am looking into some suspension upgrades. I am happy with the 030 sport suspension on the road, but there is some strong understeer in autocross conditions (esp. lower speed, sharp corners). I am still playing with tire pressures, and haven't experimented (yet) with alignment settings (and don't know what they are right now), so perhaps these will solve the issue, but I am also looking at adjustable sway bars.

I am presently in SCCA SS class, and as I understand it, I can change the front swaybars, but not the rear.

Some questions
1. Is it "advisable" to change out the 030 front sway bar for the adjustable GT3 swaybar? I.e., without changing the rear sway bar? (I do know that I'd need to swap the droplinks too.)

2. Correct me if this is wrong, but if I want to correct understeer with only the front swaybar, I need to soften the front setting. Does the GT3 swaybar even get softer than the 030 (fixed) setting?

3. Does Porsche make any "factory options" for swaybars that are adjustable, and were available from the factory in 1999? As I read the rules, I could use these and stay in the "stock" class--even on the rear. I don't think the GT3 was available in 1999 unfortunately (Is this wrong?).

4. Does the ROW 030 package lessen understeer compared to stock (or USA 030)? After searching the archives here, I have seem some brief comments that this is the case.

5. In general, what has be done to a 996 to improve autocross handling while still staying in the "stock" SCCA category?

I am just gathering data at the moment and would love input! I do use this as a weekend driver as well, but at the present I don't do any D.E. events (at least not yet).


Car Info:
'99 996
Aero Kit II
030 (USA I think)
Sport seats
Sport wheels (18")
Michelin Pilot Sports
Sport Exhaust
Traction Control
Locked Differential
3-spoke steering wheel
No cup holders
No bra (clear or otherwise)


________________________
Jeff LaCombe
'99 996 Aero
'88 944TS (Silver Rose)...sold

 

Sorry, I can't answer much, but the GT3 front bar is stiffer on its softest setting than any of the stock front bars. Since the 986/996 share most of the front pieces, you might be able to find a softer bar (who knows off a Boxster 2.5L?) since there are a lot of variances depending on year, US 030, RoW 030, etc. Sometimes the PET catalogs will list bushing sizes which is a tip-off for the bar diameter. Can't comment on classes, but the GT3 MKII was only imported to the US after '04 if I'm not mistaken. BTW, congrats!

 

why just tune with sway bars? you can do the same with camber. Just crank the front camber in instead of trying to soften the front.

 

I do plan to get an alignment, and maybe that'll do the trick. I did want to do my homework though. As I understand it, the most negative camber I am likely to get is -1 degree in the front, unless I put in different springs. Of course, -1 degree may be plenty. I wish I knew what the current setting is for comparison!

Anyone know if I'd need to get a new alignment if I changed the stiffness settings on an adjustable swaybar? If not, it would be easier to tune than alignment changes (and probably cheaper). Heck a few tries at alignments would cost about the same as the adjustable swaybars.

___________________________
Jeff LaCombe
'99 996 C2 Aero
'88 944TS (Silver Rose) sold

 

On a stock suspension, more negative camber will help the front stick more. There is a very limited range of camber adjustment in the front, though. Don't forget to play with tire pressures a bunch. If you make significant changes in roll stiffness (springs or swaybars), you should change the alignment to better take advantage of the reduced/increased body roll. Changing the settings of a swaybar itself, however, will not change your alignment. If you dig, you can probably find stuff like this:
http://www.cb-racing.com/boxster_030.html
Depending on your options, I think a '99 coupe 030 has 996.343.701.04, which is the stiffest factory non-adjustable bar. There is another part number 996.353.703.00 or .02 which is for M339 and/or C4S. Otherwise, PET says they are the same as the Boxster. Going to the 2.5L Boxster bar would be a drop of 21%. You could probably get the smaller bars for close to free. Less toe-in at the rear will also make the back more tail happy but more touchy at freeway speeds. Some things to think about anyway. Good luck.

 

Since I don't AX, I'm not sure this will apply but these cars are sensitive to balance. Probably the best thing to do to fix understeer is to rotate the car while braking. That is what I have to do on the track. I would start with driving style and tire pressures before trying to soften the front.

 

Something you haven't mentioned is what size tires (F&R) you are running. You can try to go up one size in the front if you are running a 225. Going to a 235 will help dial out some of the understeer if memory serves me right?

That and playing with tire pressure might do the trick.

It's been years since I Auto-X and even then I did it with FWD cars.

 

Jeff, I have a BRAND NEW rear GT3 bar still in the box that I would like to sell.

It's taking up space for all the other parts I need to stock. I ' ll look at any offer on it.


Theo