For the most part, you can, BUT! You cannot use the GT2 ride height settings, as it completely screws up your geometry and leaves you with no suspension travel.

Going too low on a TT will lead to issues with bump-steer etc. The TT's have completely different pickup points for the front suspension compared to a GT2, because of the AWD...

You CAN use the toe settings I posted and you can get a reasonable amount of camber out of your Car, but nothing near what you need to make the Car really work at the track. For that you need to go aftermarket, like I did.

Again, it depends on what you want your Car to do: Track days or straightline races.. The settings I posted, are for fairly serious track work. If you use the toe figures I posted, then be prepared for a Car that steers REALLY quickly at the front... very Go-Kart like.

Once you start cranking some camber into your Car, it will increase your caster angle (which pushes the wheels forward and makes the car steer slower) at that point the extra toe OUT at the front helps quicken the steering back up again... Think of it like a Motorcycle.. When you add caster, it's like raking the forks out in front of the bike which means it's like a Harley.. steers slow.. When you remove caster, it is like a sport bike.. it pulls the wheels backwards and decreases the rake which makes the Car steer quicker..



I have spent so long learning about Motorcycle and Car suspension and setting it up for myself and friends that sometimes my head hurts...

As a comparison, here's a previous alignment.. Look at how different my toe and caster figures are, before I got the aftermarket adjustable suspension components.. My front toe went from 1/6th IN to 1/16th OUT.. My caster was pushed all the way out to 8.3 and 8.5, so I adjusted it back more towards factory spec at 7.5.

 

GT2 Ride height can be run, it's almost the lowest the TT can run without toe issues in the back. And this is assuming you ARE driving on sticky tires on a track on a firm suspension (not stock). On the street it's no problem (other than the extra negative camber if you are concerned about tire wear). You'll need front lower control arms and rear upper OR lower control arms to get street camber levels again. Much lower than that, or with lots of DF, you need a bump steer kit to lower the pickup point and it will be fixed.

The TT can still have 0 toe or toe in set at significantly lower than GT2 ride height specs. It just can't maintain that with hard cornering on sticky tires and lots of DF.

 

Went to TC Design (suggested by f1crazydriver) at Milpitas this morning for an alignment. Interesting that they do not use any alignment machines, but they (Joe) sure know what they are doing. I was asking for something that turns in better but still comfortable at high speed. Since these things are either or, he tried to compensate both with these settings (with stock hardware). The drive feels pretty good, but I may go back and get a little more front toe-out.

Here are my current settings.

8 degree caster (didn't change)
-1.0 deg FL camber (maxed)
-1.1 deg RF camber

-1.8 deg rear camber

1/32 total front toe-in
3/16 total rear toe-in

btw, he lowered my front a 1/4" too.

 

Looks pretty decent for a road setup, but as you said, a bit of front toe OUT would be worth a try.. if you don't like it, you can always go back...

 

Exactly!

 

P.S. With our Cars, we are always searching for more front end grip (especially at the track).. you might want to consider less rear camber, if only to balance the Car front to rear.

At the track, you will find that people will run around -3.0 camber front and -2.5 rear (sometimes as much as -4.0 front and -3.0 rear, but we are talking pure race setup at that point).. The reason is that our Cars understeer quite a lot due to the way the factory sets them up and the fact that the front tires are so much narrower than the rears...

Cheers and let us know how it turns out and what differences you feel once you have the front more toe OUT..

 

Thank you for the tips. I'm taking it one step at a time. I don't want to lose the freeway ability since I'm on freeway most of the times. I'm trying to take it to a point that makes the best of both worlds.

 

Try adjustable rear toe links. You can then dial out the excessive negative camber (which will cause more toe in than the stock excentrics can handle) and hopefully the adjustable toe links can compensate. Otherwise you have to either raise the car a bit or add adjustable upper rear control arms (dog bones). Also check to see you sway bar drop links are not binding (too short). These may also need to be replaced with adjustable ones.

 

How do wider tires affect this?

Also, OP- I looked up a manual on the DWA500. Toe is measures as "Toe In" so a positive number is toe in. From the chart the column with nominal values is "the spec from the mfg." The middle number is the 'target' and the other two are the allowable min and max.

The next column is the 'measured when you got here' numbers

The last column is the 'we are done, here is what we set it to'.

The rear toe is bad, your tires will last 5k miles. 1/32 or 0.03125" is recommended... you have 3.26mm or 1/8"or .125"

How low are you?

I am at GT2 heights (996TT) with no issues hitting alignment numbers...

 

hello everybody
i am a new member and i leave in France (Paris area).
i have read this subject as i have bought a 996 GT2 last year but i still have some concern about the geo setting, and the car is not very pleasant on road.
i made a road setting as follows
Front
camber 1.3 degre
TOE in 1/32 inch per wheel

Rear
camber 1.7 degre
TOE in 1/16 inch per wheel

But i still feel some understeering, Maybe the rool bar setting ?
so i wonder what should be the ride height Front and Rear (from floor to top wheel arch), and also which position for the anti roll bar front and rear (right now i have medium +1 harder for front and rear).

thanks for the info you could provide for the 996 GT2 according to your experience.

philippe

 

My best alignment ever has been by Goldcrest Motorsports (mechanics from the disbanded Farnbacher Loles) at the track with strings and an alignment platform. Used properly, the strings are the shiznit. Pro teams use this method all the time.

Toe out in the front is better for reducing understeer. Also try looser front sway and then stiffer rear sway in that order.

 

I think that toe-out in the front is most useful for reducing understeer on initial turn-in, and that sway bar adjustment as heavychevy said along with camber changes (more negative) are more effective for mid-corner. The AWD makes it hard to dial out that last bit of understeer on corner exit. I find that aiming a few feet inside the exit curbs and letting the car drift out is about the only way to deal with the last part.

Jon

 

hi,
i understand the TOE out could help. how much will you suggest ?
the GT2 is RWD so the geo does not work the same as the 996TT and also the suspension on the front is different especially for corner exit as there is no traction on the front wheel.
then the roll bar might have some important part for a balance between front and rear ! so if anyone has an experience for a GT2 on road ?

finaly, also the ride height (which i am not sure on my car !) so if somebody could tell me the correct one (which i could measure from floor to top wheel arch) !
i think i saw some value posted by 80 Shilling but i can't find them anymore !

 

Philippe,

I use about 1.5-2 mm total toe out in front. I think that is the GT2 spec, but I am not sure.

Sway bars can be adjusted as heavychevy said - softer in the front and/or stiffer in the rear (in that order) to reduce understeer.

Jon

 

Subscribed....and I don't even own a Porsche yet. Good information resource for future reference!!!