mooty

ron, yes it can.
AWE has a write up on that.
it's on one of the forums if you search for it.

Unitah

Interesting, now, what would the benefit be of deactivating the PASM system?

Apex Late

Did you try the car with TC off and sport mode not selected? I did the former (it helped) but not the latter. .

Hey Bob,

Yes I tried all of the combinations that I could think of. Only Sport, Only TC, Only PASM and then all of the combinations of the three. I could not make that PASM work in any condition it seemed to only make the negative condition worse. I suspect that this is because it made the suspension firmer and as such enhanced an already poor set-up.

Apex Late

[QUOTE=insite]running a wedged ride height will reduce understeer. it also has the effect of adding some downforce to the rear of the car at speed.

Ok. I can understand that. Can you recommend a front and rear ride hight that may work?

doc2s

ONLY if you are replacing the stock dampers to avoid a CEL.

Apex Late

+1

frayed

Deactivating PASM puts the shocks into limp mode. IIRC, they get stuck at the stiff setting (PASM button on). Maybe worth trying but I doubt that it will fix what ails you.

Disabling PASM would be useful when fitting some better dampers like a set of JRZs or Motons though, since the PASM shocks are tarted up Bilsteins.

Apex Late

Unitah,

Can you tell me what your ride height is both front and rear? My research today suggests that our original assumption that more would be better is incorrect. I went beyond your settings when I did mine and it seems that this suspension really won't respond well to being this low. I was informed that 15mm lower should be the max and that the car will perform best between 10mm-15mm. I seem to remember that you dropped yours about that much but I could'nt remember exactly.

I think that you are VERY close to correct on your existing settings. If you add the additional camber up front you may be just about perfect.

Unitah

Apex Late,
Indeed, you are absolutely correct, I dropped the car about 1/2" all around on the initial go (so that would be 12mm). The car is a million times better then it was on delivery, but then again on delivery, each wheel had a different camber, castor, and toe setting, hahaha. It was funny, I think the guy who did my alignment at the factory was blitzed out of his mind. -1.0 front left, -0.25 front right, -2.2 rear left, -1.7 rear right, hahahaha. No wonder the car wouldn't drive straight, hahahha.
So, getting back to what you said, I too think (hope) I am very close to where I want to be. The slight understeer remaining I hope to correct with 1/16" more toe OUT in the front, and 0.25 more negative camber in the front on each side.
After doing a little more research today, I feel the high speed instability I am feeling in the *** is more aerodynamic in nature. So, I may try a Cup Car front splitter to decrease the airflow under the car as much as possible. I will also do the rear toe links from the Cup Car, as that may be the issue, those damn rubber bushings they use. Lastly, in case it is the engine, I am ditching the Cadillac soft engine mounts for solid ones tomorrow, so, I'll let you know...

Bob Rouleau

Apex and Unitah - As a matter of practice when we talk total toe, divided by two for the side to side. I noticed last year that Apex 996GT3 could pull away from me and I suspect that he had less toe in the rear. The Ferrari Challenge guys learned that zero toe in back gave them a serious advantge in acceleration compared to cars with a lot of toe in.

The track spec for the 997 GT3 is 16 mins a side which suggests that rear end stability is what the factory wants. On the other hand I dislike having the rear end wobble on high speed sweepers.

Since I hope that Ron will take my car this week for an alignment before the LCMT event, have we reached any conclusions as to the correct set up?

Unitah suggest 3 degs neg in front, 2.5 in back. Toe out in front and 34 mns total toe in at the rear.

Best,

Apex Late

Bob/Unitah,

This is what I think so far:

Front camber -3.0
Front Caster Max
Front 1/8 toe out (total toe)
Front sway bar full soft
Front ride height lower by 12 mm

Rear camber -2.5
Rear caster Max
Rear 1/8 toe in (total toe)
Rear sway bar full stiff (or one from full stiff depending on preference)
Rear ride height lower by 12 mm

8 degree attack angle on the spoiler with a cup spoiler on the front (no brake duct version to reduce the air flow further at high speed) These are available from Gert and my only concern would be brake cooling. That being said I think that there is more air going under the 997 than the 996 because of the cooling holes and the reduced front lip. Just a thought based on Unitah's high speed comments.

Unitah, does this jive with what you were thinking? The only thing that I'm not final on is the rear camber. I may choose to run even less camber in the rear.

Apex Late

Unitah,

Also could you measure your actual ride height from the ground to the top of your wheel wells? My car has already been lowered and I want to make sure I get the correct heights. I'm told that my car was lowered 17.5 mm but I want to be sure that the end values are in line with yours. Would you mind posting your actual ride heights front and rear?

frayed

Funny you say that. A race shop suggested the following to me:

"Rear lower control arms

Rear toe links

Spacer blocks

Rear up rated motor mount kit

The 997 Gts3 is a great car out of the box, but can be very intimidating at higher speeds. All of the items work extremely well and help make you a better driver by allowing the car to be much easier to drive


The rear control arms are mono ball and have adjustable caster settings. The toe links also have inner/outer mono ***** and have a drop spindle to correct for the bump steer in the rear that theses cars suffer from. . .

The rear control arms make for a longer wheelbase. The spacer blocks allow us to fit the mono ***** in the rear."

I think the rear toe links are the most crucial components for stability under high loads, from what I've read. I'm going to do those first, a track oriented alignment and focus on driver for a while.

Bob Rouleau

Hmmm I am reluctant to lower the car since I have enough trouble getting into gas stations and parking lots. My neighborhood has speed bumps and dips. I will be condemned to have to follow Apex.

I wonder if the PASM PSS9 kit would help with the understeer problem. I am suspicious of the roll bars. My observation is that initial turn in is good. The push comes mid corner and thereafter. Is this a result of the shocks getting stiffer (PASM has a reaction time after all)? My previous experience was that shocks can have a dramatic effect on handling. I once tried race shocks and springs. Talk about STIFF!. I decided to use softer springs. Guess what, the car was just aas STIFF. The difference between a 1200 lb spring and an 800 lb spring was masked by the shocks.

Apex Late

I was given the exact same information today. BUT I would like to get as much out of the stock parts as I can before starting the upgrade process. That being said I'm sure that these purchases will not be too far in the future.