Ubermensch

I've got a 2001 C4 that I occassionally run at the track but drive on the street 90% of the time. When my ***** joints started squeeking I replaced the control arms with the adjustable GT3 units. Until now I've run them with the stock setup (1mm spacers) adjusted to almost no camber (0, -0.25). Should I consider running more camber for the street and DEs? I'm not really interested in running through tires in 5k miles but I would like to ensure I'm getting the most out of my setup. Any suggestions on adjustments I should consider? I've got a three day DE coming up so I figured if I'm going to make a change, now is the time.

Thanks,

Shawn

todinlaw

In my GT3 the stock street set up was like 1 to 1.5 negative camber, and go to zero toe that is better tire wear.

CWhaley

if you street more then track the it... keep the toe (as todinlaw states) near 0, do not go over 1 Deg 30 minutes of negative camber and keep a .5 degree spread between the front/rear (ie. front 1 degree ~ back 1 1/2 ) Without lower control arms in the rear (you did not state you replaced all 4 corners) 2 degrees 30 minutes is likely the most you should be able to reach (if the car is lowered). The key is to keep the car set up with the undeersteer that came factory for street driving. You will still enjoy the car as a DD and can learn the limits of your car at the track.

Ubermensch

Correct, I do not have adjustable control arms in the rear. I'm currently at 0 Toe as you've both stated.

CWhaley, can you briefly explain why maintaining the factory understeer is important? Is this strictly a safety issue on the street?

Glen

Surely I'm misunderstanding, never want 0 toe in the rear of 911...

Veloce Raptor

I was thinking the same thing. Isn't toe in--even a tiny bit to minimize tire wear--the way to go?









Professional Racing and Driving Coach

997gt3north

my suggested setup for your needs (mostly street, few track days, fun at the track, decent tire wear)

front
-1.8 camber front with zero toe

rear
-1.3 rear camber with 2mm per side toe-in

reasons
- disagree with earlier post about keeping more rear than front camber
- you want the opposite to dial out the excessive push dialed in by the factory
- the above setup should make the car more neutral

- the fast tire wear on 911s comes from too much rear camber (inner edges get corded) while street driving
- therefore, giving yourself some will help on the track from killing the outer edges, but not too much - this will slow the inner edge wear rate
- the increased front camber will get the car turning (big plus)
- because the front of the car weighs so little, tire wear in the front on the inner edge isn't really an issue even running -2.5 camber but getting it up to -1.8 will save the outer edges while at the track and make the car more neutral (a good thing)

- front toe at zero - makes the car turn-in much better (a good thing)
- rear toe at 2mm per side toe-in - keeps the car stable under braking, keeps the car from turning into a helicopter (also a good thing unless you are going drifting)

- the above setup, with decent tires kept at good pressures while on the track, should make your car noticeably "better" on the track than you have experienced in the past and still be perfectly fine on the street
- if you want to make it even more "streetable", just change the front toe to the tiniest bit of toe-in (1/16th total toe-in), this will make the daily driving "easier" - the car will wander less - that said, with zero toe, fresh tires and a fresh alignment, the car should will also be perfectly streetable

utkinpol

your rear axle can go to about of -1.8 degrees of camber if it is stock keeping toe at 0.10
so go to alignment shop, tell them to get max negative camber in rear keeping toe at .10 then based on what they will get put -0.3 degrees more in front, like i you got -2 degrees in rear use -2.3 degrees in front. on my car left side needed 2 7mm shims, right side one 7m shim and one 3mm - not sure, your mechanic will need to figure it out how many an which shims are needed. it probably would make sense to put adjustable compression links too in front so you could adjust caster. Set front toe to 0 or to 0.02

if you put same GT3 front LCAs into rear axle (it fits) then you`ll be able to get more than -2 degrees there, for street/track car ideally -2.6 front -2.3 rear would do. More than -2.5 degrees in rear on a street car will eat up your street tires inner edge too fast. for track only car you can set way more like -4 degrees front -3.5 rear. it all depends.

mooty

i would presume they are talking 0 toe up front.
0 toe in rear..... you shall have intimacy with walls.

CWhaley

My feelings are this: Keep fatctory undeersteer wih 0 to slight - toe front for a DD Street car (light use track car) Becasue....

You will have a car that can still be driving by your wife, son / daughter, best friend, parking attendent (whom we all know might take a short trip) ...

When you start setting the alignment up with neutral steering it really evolves into a toy that is limited in use to those with some skill or a dedicated track car.

I would never want either of my 20 something sons driving the 911 out at night set up like that....

Viperbob1

Hey Glen, how is it going? Was watching you at the 24 Hours of Daytona. Nice job... Hope all is well...

944CS

here is a 996 set up with zero toe F+R, notice how the car turns with less steering wheel input
http://www.youtube.com/watch?v=5zmZqIObQtM

mjb

+1 I think this is the most sensible compromise setup on street tires for a car that is DE'd occaisonally. As mentioned 0(or slightly neg) Fr toe will give the car a little less straight line stability on the street then dialing in some slight Fr toe-in.

todinlaw

Bingo, discussing up front camber up front toe, in my post anyway.

CWhaley

I think we are all speaking to the front toe...

What this really comes down to is : What are your expectations and goals for the car, then set it up to meet your needs.
You can get 12 of us in a room and get 12 different opinions. Each are very valid and can work for each of us. Drivers style and skill will drive many of our set ups.

My track car is no where near the same settings as my street DD.