GreggT

Geeez, I wish I had more of a clue of what I was doing adjusting these anti-sways on the Turbo.
Right now I have the rear in the 'mid' position (of three) and the front in the end hole (least rigid)......the car is definately more rigid laterally, and I believe she's turning in a bit quicker.
My original goal was 1.)to overall tighten her up a bit more 2.) dial-out a bit of understeer, I 'thought' I had 3.) just continue making the car all it can be.....(without screwing it up too bad) .

I'm thinking I need someome (far more capable than I) to give me feedback of where they think it's at....there has to be an optimum setting for aggressive street plus track use.
What would it feel like if I went too far ( too tight laterally for my own good).....what's the downside here?

Any input appreciated.....thanks in advance.

Steve Weiner-Rennsport Systems

Hi Gregg:

I'd be more than pleased to help if I have more info,....

Torsion bar sizes?
Swaybar sizes? Brand?
Wheel size?
Tire Size?
Camber settings

Your experience level? (these cars are not very forgiving at the very edge)

GreggT

Steve.......thanks for the offer of assist:
This is on a Roock modified 01 Turbo.....Gemballa/H&R coilovers....H&R adjustable anti-sways (25mmfront, 24mmrear).....S-Car-Go DLs.....Track wheels are OE hollow 18s (8J,11J) and Sport Cup OE size (225/40 & 295/30).........daily fitment is 19" HRE, but I think I'm primarily concerned w/finding the best combination for the track.....front camber -.6 and rear at -1.9 ("part" of my reason for continuing to try to stiffen her up was to try to use a bit less neg camber...& get a bit more tire life....19s in the rear are $625 a pop ).
The -1.9 is a tad more than I'd like but I'm at the end of my adjust (car is fairly low). Some have told me to look into a GT3 lower control arms project if I realy wanted to address that.

Anyway.....driving ability...been tracking 8-10 yrs....(1st w/944, then 993, which I still autocross)......top run group at track DEs, Tracktime, etc.
Again, thanks for the offer of providing a few tips.........wish I was sharper in this dept.
These cars are so fricken incredible (no matter what you do to them) I'm just trying to do the right thing here.

Steve Weiner-Rennsport Systems

Hi Gregg:

Nice setup, Sir. My compliments to the "Chef".

Everyones tastes and preferences differ, but I'll offer some baseline suggestions based on your objectives and needs.

Given your desire to balance tire wear against grip, your current alignment is biased toward understeer (as you know) and you will need to tweak the chassis balance with the swaybars unless you dial in more front negative camber. Remember, the wider and lower a tire you use, the more neg camber they like to keep those treads flat on the ground in the corners. Its a tradeoff,....

Currently, your bar settings are providing some relief against understeer and you could tighten the rear bar one more hole, if you are experiencing excessive low-speed push. If that doesn't help, I'd put your front camber at 1.0 deg neg, if possible.

If you tighten that rear bar up one more notch, the car will certainly get more neutral and turn quicker. Its a question of degree but if you are paying attention, it should be better for you. You are the sole arbiter of what YOU like. With AWD and PSM, the car will not bite you unless you aren't "listening" to what it is communicating at track speeds,....

Questions?

GreggT

Good tips all around...thankyou sir!

Final questions.......(and right in line with your comment on 'listening to what the car is telling me')....my goal is trying to be aware of what to listen & watch for (if I go too far in adjustment one direction or the other).
If the car is (over-all) set up too stiff, and the springs do very little in the corners (my independent suspension is less 'independent' ) I might watch for the car being too easily upset by bumps, etc, in the turns..........sound correct?

On the relationship of front-back settings (being different)........I'm going to assume that the main (are perhaps only) resulting byproduct here, is increasing-decreasing oversteer-understeer.......anything else big happening here?

I read today that a car that had significant oversteer, would also require more attention (& have less stability) in a high speed straight?......sound plausible?...again, just trying to know what to watch or 'listen' for, especially at incorrect limets.

Thanks again.

Steve Weiner-Rennsport Systems

Hi Gregg:

You are correct, a car that is too stiff will get displaced easily by bumps and such. Do not mistake this though, for an aggressive suspension that might not be driven hard enough. This is why its SOOO important to match the suspension components and setup to the driver.

Yessir, stiffening the front (relative to the rear) increases understeer. Stiffening the rear (relative to the front) increases oversteer. Due to weight distribution and swaybar geometry, stiffening the rear swaybar makes little a bigger change in balance, than stiffening the front.

Once again, right on. Due to the rearward weight distribution of these cars and the Polar Moment of Inertia, these cars tend to understeer at lower and mid speeds to prevent it from being too "loose" at high speeds. LOL,.....Its all a tradeoff and one must be very very careful when dialing out understeer so that it won't get away from you at higher speeds.

This is one reason why race cars reply so much on splitters and wings to provide the high speed downforce when using a neutral chassis setup,....

SPR

Yeah that is all in the right direction. Are you concerned about how it is much stiffer as you have tighened up the rear and the ride has sacraficed itself a bit? You are running a pretty agreesive setup for the alignment and given your needs of limiting tire wear, I would say you're battling your rear preload. You just need to make a decision of what you want, tire wear and harsher ride from more preload or less tire wear and a bit more compliancy? You could move the rears back out to 1.4 or 1.5 neg. and then the understeer would reduce a bit and leave the bars loose front and min hole rear. You would be sacraficing your handling somewhat but the preload would reduce (maybe) but moreso it will reduce the understeer while working around your concerns. Also have you had the car corner balanced when you did the alignment? Definitely better and makes thing easier to "read and feel" consistenly. Sounds like you want your cake and eat it too! Steve was right on with everything he said.

GreggT

Sean
Thanks for adding your 2 cents also.
On the corner balance........that has not been touched since coil-over installation & ride height adjust (some time ago)..........think it's worth revisiting? Visually, it appears the back left is lower that the right (looking at the top of the wheel arch and puting a couple fingers in there.......I'm having the shop today take a couple of actual chassis height measurments.

On reducing rear neg camber a tad.......I have a problem there, cause she is so low, I am at the end of my adjustment there......not happy about that cause -1.9 is a but more than I'd prefer....Only ideas that have been thrown at me so far on that is possibly a conversion to GT3 lower control arms (adjustable, but also would require some modification) and might also need solid bushings.........not real keen on jumping into this project quite yet.
Any other suggestions welcome (and appreciated).
She'll be on the track again next weekend and I think I'll devote the weekend to trying all different settings on the bars......I just hope I'm able to recognize a good thing.
On the other hand......if I can't, then obviously the settings not that critical (to this driver anyway) ....nahh, that's the wrong attitude.
As I said early-on, my goal (like most of us) is continuing to make her all she can be.

SPR

Ah yes I forget about the lowering with the negative camber fiasco. The adjustable lower control arms would allow you to get more positive at the ride height you want. Did you corner balance the car in the beginning? It sounds like also you might not have your ride heights pretty much equalized around. If you do notice such a variance then that might be a good idea but more thought before paying out dough is good as well with what you want to do. Well it is a tough deal as you don't want to bring the ride height up enough to bring the rear camber more positive. It is also difficult as you are trying to balance ride quality with MAX performance and tire wear. I am was told that concerning your fronts going more than -.7f will cause premature wear. I am running -.5f and it seems fine. I also kill those tires through the canyons so.. yeah. I am wondering if you brought the ride height up a bit and at the same time having it equal all the way around with you in the car doing the corner balance, and thereby bringing the rear in to about -1.5 then you should make the car more neutral without increasing the harshness of the preload of the sway bars. Too bad you don't have quick releases with safety wire on the bar ends so you could make a couple back to back comparisons on how much firmer the ride is with stiffening the rear bar more to bring it into a more neutral setup.

I would say that the thing to do first is to go drive through a canyon or somewhere where you can get on it and really memorize how it is pushing and a ride through a crappy street for the ride quality. Then change the rear bar a hole in to increase it's stiffness and then do the same tests again. If it is too annoying to put up with then your answer is not to play with those settings other than if and when you track it. If that's the case then I would raise the ride height up a bit do a corner balance with you in the car, and bring the rear back out to about -1.5 and the front out a bit for your wear balance. The main thing is that it's a balancing act you would want to either leave the negative in a bit (take out less) and add more positive rear. Basically you're just doing the same dynamic as with the bars although the bars affect the opposite ends of course ala torsional twist fore and aft. I think that if you don't want to add more rear bar, that if you go -.5f and -1.5 or a tad more then that will get the affect you desire. Since you have the h&r's I don't think that the dampening on the struts is adjustable like the pss9's are or else you wouldn't be as concerned as you are about the degredation of tuning the bars. Incidently I am running -.5f and -1.5r and the front wear is fine and understeer is managable.

SPR

a couple of other thoughts. What is your front sway bar set at? All the way loose? If so cool. If not put it at the end hole. YOu will want to bring the fronts out to -.5 what you do with the rears is up to you but if you put them at -1.5 then the balance will be much better neutrality wise. Another thought beyond the camber is, I know it sounds weird but you changed the bars front and rear right? What about if you were to put the stock bar back up front to give you even more looseness? Just a thought. Another thing I wanted to mention is that I split the front toe setting between factory and 0 to make it turn in better. Big difference made it nice to enter a corner. It did make it meander more on the freeway a bit etc. but I can deal with that.

All in all though with what you want I would say that if you want and need to reduce front tire wear then bring then out to -.5 and put the rears where you want. I came up with the settings I use after much discussion with Dan the head mechanic tech. at BY Design. He is very knowledgable. You might try and give him a call to further shoot the sh*t.

GreggT

Sean.....thanks again for the input.
Yes, the car was corner balanced when the Gemballa/H&Rs went on and we were originally setting the overall ride height.
My main goal right now (along with arriving at the ideal bar settings, is to find a way to get less neg camber in the back w/o raising the suspension back up.......if that is possible).

The -2 degrees is fine on the track but my daily 19s have $625 tires that I don't want to go through that quickly.