Question about camber/caster

I have no idea what kind of car your thinking of racing, so... FWIW:

You already have a good starting point with your 2.2 degrees negitive camber thoughts. That should be enough to get you in trouble. As for caster, go with a pretty stout number for track use. 4-5-6 even 8 degrees is not out of line. It will effect how the steering feels, so go with what you like. Toe will be effected when you change settings. Look for .05 toe in each front wheel to start. Perhaps .10 toe in per rear wheel for stability. Play with some settings and read your tire wear (look to the sidewall) after each run. If your eating up the tire edge then add additional negitive camber & try again.

Read some chassis set up books. They can be found everywhere!

 

Agressive camber settings are streetable, and will improve your turn in on the track, however you will be eating up tires left and right (not as bad as excessive toe-in, but on the street expect to see far less tire life). 2.2 is high, but deffinatly not the highest one can go with neg. camber setup. Many daily driver auto-x cars are running -3+ degrees of camber and not running through as many tires as you would think. Caster if I remember correctly (which I may not, as I am not a suspension expert) will make the car "feel" more neg. camber, but without the ill effects of high camber numbers (the only downside is the steering become heavier, which is a major downside on an f-car ;-) )
hope I was of some help... Anyone hwo knows more (which isn't saying much) feel free to correct me.

edit: also make sure you get your cross toe and cross camber as close to zero as possible. It can be a PITA, but will make the hundreth of a second difference on the track.

 

Kami,

The best advice i could give you is to read up on vehicle dynamics.

My all time favorite racing tech writer is Carroll Smith, MASSIVELY experienced, from the almost highest ranks, doesn't dance around, very plain spoken and humorous, a distinctly unusual combination.

If i have had a really bad day at work, or even worse a volcanic arguement with my wife -- I can pick up a Smith book, settle down a bit and everything is OK.

If you are mechanically interested, the entire 20 year series, (+ - 6 books) is a gold mine, (and entertaining).

hth,
chris

ps just do a google on "Carroll Smith"

 

Your car will determine what settings you are capable of achieveing and what settings you will need. +/- camber and caster etc are totally irrelavent without the car's suspension as a point of referrence. You can read about what those things are and what they do but the absolute numbers mean absolutely nothing until you hook a suspension to them. Once you have a car to race you pick generic settings based on the factory recs. Then you tune those settings for what you are tyring to achieve on the specific track you are racing. In racing you are tuning suspension on the car for "the specific" track. Those setting can be quite diferent for a different track.

 

If you want to fine tune your toe, camber and tire pressures, you need to read the temperatures across the tread immediately after a run (beit an auto cross or track laps).

Longacre makes a pretty decent tire pyrometer with memory (the computer interface is worth the cost option, I have it on mine).

The Longacre "toe plates" make short work of setting/checking toe (I generally keep my cars 1/32" to 1/16" toe out). You want some load to keep the front end from wandering, but generally speaking, toe in induces understeer. I don't know how detrimental an effect toe out has on high speed stability, so do your research; it's no issue at 120-130 MPH.

I also use a "Smart" Camber gauge to check/set castor/camber.

All three (3) of these items are relatively inexpensive and easily carried to and used trackside.
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++1.........if you are building a car from scratch, I might add that before you even get to his point you are going to have to determine weight distribution, ride height,spring rates, shock valving, and to some degree sway bar stiffness...........dialing in any race car, especially a one-off is very tedious.......back in the 80's we had a $300,000 tube frame porsche GTP car designed by Lee Dykstra(F1 engineer) that we never got dialed in perfectly.