Edward

If I have more neg camber dialed in, is the Kinematic affected, or can I leave it alone?

Some background: the car behaves well/neutral on the street and track. I'm looking to improve "stick" if I can (camber currently at -.7F/-1.2R). After my last track event, I just noticed that now that I've worn my Kumho Victoracers down to nothing, the wear is pretty even except for the innermost edge of all 4 tires...considerably more rubber there than everywhere else across the face of the tire (there's actually some tread there). So I'm thinking maybe I can get my local, trusted independent (who also races SCCA) to dial in more camber, but I know he doesn't have the wherewithal to adjust Kinematic. Opinions from those "in the know" whould be greatly appreciated! TIA

Edward

Martin S.

Call Mike Schatz at Rusnak in Thousand Oaks. He runs a parts business by night and "wrenches" for Rusnak by day. He is one of the best I know of in So Cal...Directions..down the hill and take a right at 101, snak through Sima Valley, the back way.

Bt the way Ed, I don't know what you expect from the Kumhos.. I get 2 events out of mine. By the 3rd event, at least one tire is getting bad.

Try Michelin Pilot Sport Cups...great write up on these tires in the last Pano.

Edward

Martin,

Thanks, I'll try Mike. As far as the Kumhos, I've heard lots of varience regarding life expectancy; 2-3 events is on the "short" side from what I've heard, but that's probably because you're all much faster than I am! I've heard that one can drive Victoracers until cord shows, so that's what I'm going to do.

In terms of camber, I'd like to get a bit more as mine is a bit conservative, I think. And if I can get away with not having to do Kinematic, that's gravy.

Edward

tom_993

Edward,
Aligning a 993 appears to be as much black art as it does mechanics. I wouldn’t want to have it done by someone who doesn’t have the proper tools and/or knowledge to adjust kinematic toe. This is a critical adjustment. I’m not sure whether adjusting camber changes the toe or not, but I wouldn’t want to chance it. This is not to say anything about your trusted independent. Kinematic toe on a 993 is just a very specialized kind of thing.

Tom
’95 993

Ted Brewer

Edward:

I do not beleive it will be necessary to reset your Kinematic toe. I just had a PSS-9 set-up installed along with adjustable camber plates (monoballs) up front and we set all four corners at about 2.2 degrees camber and we did not adjust the Kinematice toe. The fellow who did the corner balancing and alignment is a very knowledgable racer/technician and he saw no need.

Ted

Edward

[quote] I’m not sure whether adjusting camber changes the toe or not<hr></blockquote>

Yes, this is the crux of my question. Anyone know the answer to this? Believe me, I don't want to "fix" one thing while screwing up another, which is why I'm wondering aloud here.

Edward

EDIT: Ted, just read your post. Thanks!!!

Tom Trew

Edward - I am afraid adjusting camber does effect Kinematic Toe. The adjustment sequence per the service manual is:
1 Toe
2 Camber
3 Kinematic Toe

The earlier adjustments effect the later ones. The manual also states that "if only toe in has to be corrected (camber OK), then the kinematic toe does not have to be checked".

The manual also says that if you adjust kinematic toe, that you need to make sure camber did not change. In other words, the two adjsutments effect one another and must be done somewhat iteratively.

Ted - I suspect your shop just did not want to get into the kinematic toe issue. Having installed PSS9's on my car, as well as lowering it considerably, I will tell you that kinematic toe does indeed change. Any significant change made at the rear of the car will cause changes in the kinematic toe setting.

Hank Cohn

Edward:

Tom is correct. Anytime camber is changed, then kinematic toe will also change. Anytime ride height is changed, camber will change. The sequence Tom listed is also correct, but it is very iterative. In other words it is not a one time through and you are done. As you adjust kinematic toe, camber and toe change, so you have to keep going through the process until you nail it. There is a trick that you can use, however. The 993 RSRs used for racing almost always maxed out the kinematic toe adjustment. You do this by pointing the longest of the index lines on the kinematic eccentric adjuster straight at the motor and parallel to the ground.

As far as alignment goes, and this is a little aggressive, if you are using your car for mostly street and a little track, I would recommend 2.0 degrees negative camber in the front and 1.5-1.6 degrees negative in the rear (this will adversely affect street tire wear) if you intend to use Kumhos, Hoosiers, Michelin Pilot Sport Cups or Toyos. If your car is more of a track car then you can pick up more grip and cornering force out of all of the aforementioned tires by changing to 3.0 degrees negative in the front and 2.5 degrees negative at the rear. Also, if you are racing, don’t forget to toe the front out a little (1-2 mm) and toe the rear in a little (1mm).

Hank

Edward

Tom, Hank,

Thanks for the specific information. This is what I needed to know, but not necessarily wanted to hear.
Oh well, off to get a "real" alignment. Thanks again, gents!

Edward