Alignment for track

[Jittsl]

If Brad hasn't made it clear enough - rear tow (or lack thereof) is more critical than camber.

I would try:
Front camber - as much as you can get
Front tow - none
Rear tow - no more than 1/16" (I run none in my spec Boxster)
Rear camber - whatever you end up with as long as its less than the front.

A soon as the track pipe takes hold buy yourself some GT3 lower control arms (more camber in front) for the front and some adjustable Rear Toe control arms (right combination of toe and camber in the rear). Until you do I suggest you will find it hard to dial out the understeer to your satisfaction.

I would not screw too much with tire pressures. For not much more than the price of a set of tires you can make the mods above. I would hate you to waste the money on ruining a set of tires. In your attempt to remove the understeer you are already reducing the performance of the rear by reducing the camber which will take a toll on the outer edge. Lower the pressures and you will increase the flex (in another attempt to reduce the performance) and further burdening the outer edge.

[san rensho]

Originally Posted by Jittsl

If Brad hasn't made it clear enough - rear tow (or lack thereof) is more critical than camber.

I would try:
Front camber - as much as you can get
Front tow - none
Rear tow - no more than 1/16" (I run none in my spec Boxster)
Rear camber - whatever you end up with as long as its less than the front.

A soon as the track pipe takes hold buy yourself some GT3 lower control arms (more camber in front) for the front and some adjustable Rear Toe control arms (right combination of toe and camber in the rear). Until you do I suggest you will find it hard to dial out the understeer to your satisfaction.

I would not screw too much with tire pressures. For not much more than the price of a set of tires you can make the mods above. I would hate you to waste the money on ruining a set of tires. In your attempt to remove the understeer you are already reducing the performance of the rear by reducing the camber which will take a toll on the outer edge. Lower the pressures and you will increase the flex (in another attempt to reduce the performance) and further burdening the outer edge.

Ok. I'll just get a conservative alignment done and keep the tire pressures the same all around, which works pretty well now, and see how it feels.

[Brad Roberts]

I want you to learn your car. You ran motorcycles!! I know.. know you can balance a bike with the throttle on two miniscule contact patches!!

Disconnect the front bar for one session.

Then disconnect the rear bar for one session.

You can zip tie the drop link in the rear to the toe link (they both move at the same rate)

and you can zip tie the front drop link to the upright..

you'll need two wrenches..

People flip out when I tell them to do this.. lol don't like it? come in and put the drop link back on. I do it on grid during a pit stop/driver change...


B

[ChrisZang]

for what it's worth, here is my alignment:

front -2 neg. camber (GT3 lower control arms)
rear -2.5 neg. camber (with just a tad of toe in) with adjustable toe arms

PSS9 + Tarrett front and rear swaybars and drop links

just by using lowering springs you can reach up to -1.25 front and -2.25 in the rear (also here you need adjustable toe arms)

I went wider for my front tires to 225/17 front and kept the rears the way they were 255/17

[Mrmaddbrad]

For what its worth:

Everyone has been avoiding the sad truth... THESE CARS UNDERSTEER!! its the sad truth about mid engine cars....

There are only a few ways to change this in most mid engine cars...
1) Mass amounts of front negative camber
2) Tire Pressures
3) Tire sizes
4) Suspension...

Most of these have already been touched on, and i know you want to keep your car stock so here we go....
1) This option is out of running, stock suspension will never get you over -1.0 degrees of negative camber in the front, and sadly, this isn't enough But should defiantly still be done if you're trying to get the best performance/handling out of the car.

2) Again, should still be done but will not magically turn off your understeer... You mentioned running lower tire pressures in the rear. Wrong school of thought. As a rule of thumb, lower pressures means more grip. So if anything run lower pressures in the front. Porsche recommends 29 Front 36 Rear (which is a 7 PSI gap compared to the 5-6 PSI you were thinking about running)

3)Okay here we go. The magic number here is 245s all the way around. They fit in the front, and in the rear. For autocross i've been running 245/40/18 Hoosier A6's all the way around. I know you're not Autocrossing, but its still a good number to run with. Keeps the car very well balanced.

4) Obviously out of the running if you want to keep the car stock.

My '02 S is also bone stock, and seemed to find its happiness after completing the first 3 of these. An aggressive alignment is very needed, and playing with tire pressures really makes you learn your car. After it is closely balance with tires, playing with tire pressures can make you find what your car is actually capable of. However, i have no idea what to recommend for track racing on that front. Maybe ask some one else where to start, or just get out there and try it!!

Good luck!
~Brad
Cheers!