todinlaw

I just finished my 6th track day at Nelsons Ledges (ohio) and I really cooked my Left front tire. I have been told that Porsche deliberately sets up the 3 to understeer because it is safer to learn and not spin. I am getting to the point that I am more confident with the car and want to fee it up some and will maybe pick an intermediate point between the street and track set ups on the camber and toe adjustments.

Q1 how does toe adjustments affect the stability. The front toe for example goes from street +6 degrees to 0 track and the rear goes from +13 to +16. so i am trying to understand how decreasing toe in the front makes it turn better.

Q2 going to 0 toe, will the car become unstable or wander on a fast back straight?

Q3 I note that the owners manual gives camber values for just front and rear. does anyone treat the right different from the left since generally we are making right handed circles? your thoughts would be appreciated.

997gt3north

A1)
- think about those commercials with those cars that have head lights that turn to the right or left as you go around a right / left corners
- as the toe goes from pointing in to zero or even pointing out (I am using 1/16th toe out), the car will get around the corner better
- the toe in on the rear is for stability
- while a zero miles per hour on a alignment rack it may be at toe in, at 150mph braking down to 60mph to take the corner, the rear toe in actually goes to a more zero toe position as the toe s forced out
- just like in the front of the car, if the toe goes to 0 or toe out, it will want to turn-in faster
- the rear of the car is not something you generally want turning faster unless you are in a drifting competition
- that is why track is set to more toe in as the loads are higher

A2
- 0 toe will still be fine
- when you go to toe-out the car will wander

A3
- if you bring a track crew with you, you will of course set up the car so that it is fastest around your specific track
- if this is not the case, most guys balance the car left and right

My suggestion for a better setup for you is the following
You will get good tire wear (front and rear) and it will be a good driver on th street and on the track

Front
- camber -2.4
- toe 0

Rear
- camber -2.2
- stock track toe in


For reference, my current setup is listed below (and i drive it on the street with no problem)

Front
- camber -2.8
- toe 1/16th toe-ot

Rear
- camber -2.3
- stock track toe in

todinlaw

Thank you so much for your information. now for my dumb math question, How do i convert your toe in settings with the car manual you and other discuss toe in tenths i.e. 1/16 and the book uses .13 I know there is math in it some place. is 1/16 = to .

Car setup is involved. With Tire pressure, sway bars, alignment issues we have allot of variables to play with

On air pressure I assume we are just shooting for the temp the delivers an even temp across the tire?

sasportas

Hey Paul,

I guess we're both sticking to the same alignment. I'm going to try Hoosier in 19 inch. Are you still happy with the 19 inch R888? I have an opportunity to commit to new light weight wheels - I'm just trying to decide on the 19's vs 18's.

Jonathon

C.J. Ichiban

frank on the MSPC 19" OEM tire I find the best grip is in the 34-36 Psi range when HOT.

I also run a slight toe out in the front and toe in on the rear and similar camber #'s to gt3north.

on the factory stock setup front left tire gets cooked from braking or plowing through turns (generally trying to get on the gas too early)

997gt3north

I'm happy with the 19s but I have 3 sets so it is too late to change

I have used the r888s 2 more times with good results. I will be using them again next week at Mosport and it should be a lot hotter so this should be a better test for hotter weather

I will try the hoosiers next for sure

Paul

997gt3north

I just tell my guy what to do and then let him do the conversion

Let us know what tires you are using and we can give you an idea of hot temps that should be a good place to aim for

If you are using the oe tires than 32 front 36 rear worked for me - these are hot temps


Paul

AudiOn19s

http://www.ground-control.com/toe-out.htm

Frank, one note on 0 toe...I run all of my cars at 0 toe on the street and slight toe out at the track (toe moes when I adjust camber to track settings). On the street the car will trameline (sp?) / wonder some as it catches irregularities in the road surface but I've run all of my cars like this for years so it's not really a big deal for me.

Andy

AudiOn19s

Paul,
Have you taken temps on the rear tires with that camber? I know it's not an apples to apples comparison to my 996 but I'm running like 2.8 in the rear and my wear pattern seems pretty good across the tire. However I don't have access to a pyrometer.

Andy

997gt3north

- Yes I have
- for my use (50% street / driving to events, 50% DE), i had to back down the rears 2 times until I settled at -2.3
- it might be the 12" rimm, it might be the stiffer chassis, the suspension, all of the above, but the 997gt3 does not need more than -2.3 while using r888s / mpscs as a 15 DE per year + another 7000 miles of street driving at the pace I drive (2:16 Watkins, 2:12 VIR, 1:36 Mosport)

- when i had the rears at -2.7, the inside edges of the rears were past the cords and the outside edges looked absolutely unused


paul

Andrew D.

What about sway bar settings? Also - Has anyone made adjustments to the rear wing for the track?

997gt3north

Keep the sways the way they were delivered

If you want to spend a little money order the rear 997gt2 rear sway bar and put it on the middle hole - works wonders

For downforce tracks I like the rear rs Wing at 8 degrees

Paul

todinlaw

I am using the P Zero Corsa system OEM 19 inch rims.
They recommend running them at 30 hot but I have been running them at 33 front 35 rear with good results. I do not think I am running enough camber because I am slowly running off the outside half of the tire.

I think I did cook the left front from charging on vary slow corner to hard, and was plain and short just not running it well, but after looking at the tires in general I think that I am running at speed now that I need more camber. My plan is go move up slowly most of you guys have been doing it for a long time and know what to expect, I am going to make gradual changes so that I don't put my self in a car that is to loose for my skill.

todinlaw

Paul just one more Q ( don't believe it) The manual discussing the stock street set up for toe is +6'. They are stating +6 toe "in" and if I go to 0 I am going from a toe-in to neutral, and you are going to a toe-Out position on your set up do I have that right. So by going to 0 I am still not as aggressive. do I understand that correctly.

997gt3north

- Your temps sound correct
- i do not believe that you really need that many trackdays under your belt to set the car up at least 90% correctly
- this 997gt3 is actually very stable and as long as you have at least 5 trackdays under your belt i would suggest you re-allign the car to the specs at least close to what most of use DE regulars are close to