ktoonsez

I was wondering if anyone out there has come up with a formula/rule of thumb for setting there negative camber for racing. My car is pretty close but could be better and sense it costs 85 bucks to do an alignment at a good shop I don't want to keep having to back and back again.

So here is the current setup:
Front: -1.2 camber - 0 toe 275x18 Toyo R888's
Rear: -0.8 camber - 0 toe 335x18 Toyo R888's

Current pressures:
All tires at 31 psi before race (did try higher psi like other people like but didn't work to great for me)
All tires between 36-37 after.

Current temps right after race:
Front Outer: 172
Front Middle: 171
Front Inner: 166

Rear Outer: 156
Rear Middle: 159
Rear Inner: 150


Any suggestions/formulas/rule of thumb? Something like every 5 degrees of temp difference from outside to inside equals -.2 degrees of camber, something like that?

AU N EGL

Inside is too cold. might need more neg camber.

Front
camber: -2.0
Caster: Max but equal
toe: 1/16" OUT

Rear
Camber -1.0*
toe: 1/16" IN

is a good starting point. with adjustments from there.

your rear middle temp is too high compared to the side temps. Start with a lower cold air pressure.

Here is a good book to help

The Racing & High-Performance Tire: Using Tires to Tune for Grip & Balance (R-351) [Hardcover]

ktoonsez

Is this what you use or what you think I should do based on the 6 degree's in temp differential? Hard to believe only 6 degrees in temp would need an extra -.8 degree's of camber. Thanks for the great info.

J.R.

AU N GEL is correct

That is a good baseline.

The reason higher cold pressures don't feel right for you is that you need more negative and need to push a little harder to get temps up.

A couple of years ago I ran 888's a lot and found that with my C5 the higher cold pressures were faster but my temps were 190-200 deg. inside.

I have also attached PFADT's suggested starting point for alignment based upon usage of vehicle. Tire temps and pressures, along with wear pattern will determine what works best for you based upon conditions and track.

Pfadt Corvette Alignment Recommendations
These settings are a guide based on the experience and testing of Pfadt Race Engineering.
Performance Street
Performance Street - Track Use with Street Tires
Performance Street - Track Use with Race Tires
Dedicated Track Car - DOT Tires, poly bushings
Dedicated Track Car - DOT Tires, Spherical Bearings
Dedicated Track Car - Race Slicks, Spherical Bearings
Front min max
Rear
Camber (deg) -0.7 -0.9 Caster (deg) 7.5 8.5 Toe -1/16" 0
Camber (deg) -0.4 -0.6
Toe
-1/16" 0
Notes
These settings will provide good performance and good tire wear
Front
min max
-1.1 -1.3 7.5 8.5
-1/16" 0
-0.7 -0.9 -1/8" -1/16"
Rear
Camber (deg) Caster (deg) Toe
Camber (deg) Toe
Notes
These settings will provide good all around performance. The tires will wear the inside edges in street use and the outside edges on the race track. This is a good dual purpose alignment.
Front
min max
-1.6 -1.8 7.5 8.5
-1/16" 0
-0.9 -1.1 -1/8" -1/16"
Rear
Camber (deg) Caster (deg) Toe
Camber (deg) Toe
Notes
These settings will provide great track performance. The tires will wear the inside edges in street use, and the car may tend to grab the lanes of the road. Race tires will wear well at the track and provide high levels of grip. This alignment is compromised towards track use.
Front
min max
-2.8 -3.0 6.5 7.5
-1/16" 0
-1.5 -1.7 -1/8" -1/16"
Rear
Camber (deg) Caster (deg) Toe
Camber (deg) Toe
Notes
These settings are a good starting point for a car with polyurethane or stock control arm bushings. This alignment requires DOT race tires to function appropriately. This is a starting point only, testing and monitoring tire temperatures and pressures are required to optimize any setup.
Front min max
Rear
Camber (deg) -2.4 -2.6 Caster (deg) 6.5 7.5 Toe -1/16" 0
Camber (deg) -1.2 -1.4
Toe
-3/16" -1/8"
Notes
These settings are a good starting point for a car with mono-ball or spherical control arm bushings. This alignment requires DOT race tires to function appropriately. This is a starting point only, testing and monitoring tire temperatures and pressures are required to optimize any setup.

AU N EGL

I would not worry about temp differences yet

Start out with a very good alignment. ( and Yes that is what I use )

getting accurate tire temps without a needle priormeter and competent pit crew is not easy.

ktoonsez

Thanks again for the info I will do it before my next event. I am not familiar with the needle priormeter, I simply use a laser temp gun.

AU N EGL

Laser temp guns are OK, but not as accurate as the needle temp pirometer ( sp?)

and Good Luck

geerookie

If you don't have a person waiting at the beginning of pit in ready to take temps after a hot lap with no cool down then you will not be able to get acurate enough readings for settiing your alignment.
You are much better off to use some proven alignment numbers from the guys who race or DE Corvettes on a regular basis and then just work with pressures.

ktoonsez

That makes sense guys

0RAAMaudio

Laser temp units work fine for autocross where the temp is more on the surface of the tread due to short runs, etc.. for the track you need the needle, no doubt.

I agree on the alignment first but do make sure you are actually getting it done right, your regular Joe alignment shop most likely will not do it that accurately, often times way off and to some generic range that is far from optimal.

Just mounting the units on the wheels can be the start of a botched alignment, I have seem them mounted without being set on the wheel just right, it does not have to be far off to make for a lousy alignment result.

If you do not do your own you can learn to do a superior alignment at home, start by looking at David Farmers site

http://http://davidfarmerstuff.com/

kmagvette

For R888's your pressures are too low. There was a great thread about R888 suggested pressures in this forum a while back. I took the advice and was much happier with the Toyo's on the track after boosting the cold pressure as suggested by the manufacturer/rep.

If you find a thread that suggests uncomfortably high cold and hot pressures, then you found the thread I mention above.

ktoonsez

I did find a few on this forum and others about the higher cold pressure and that is why I started a lot higher at the beginning of the day but had to lower it because I could not get traction. So I am going to get the alignment suggested from the first page and try at the higher pressures again (36 psi cold). Thanks again guys

RacePro Engineering

J.R. ,

Not to nit pick, but it appears you left off the generic alignment starting points for the category "Dedicated Track Car - Race Slicks, Spherical Bearings". That is of interest to us, but I can not seem to find the proper location on the Pfadt site.

Ed LoPresti

J.R.

Ed,

Try this link. I may have messed up copying it.

http://www.pfadtracing.com/blog/wp-c...-alignment.pdf

J.R.

ktoonsez

Thanks J.R. That makes aloy more sense.

RacePro Engineering

J.R.,

Thanks - that was the "missing link" (pun intended!)

Best,
Ed

ktoonsez

Does anyone know if I will be able to get -2 camber without a camber kit or should I start looking to buy one?

waktasz

I didn't see if you posted what car you have, but on my 02 z06 I have it maxed out front and rear which comes to about -2.4 and -1.8 front and rear. Some cars get more some get less but that is about normal.

ktoonsez

The car is an '08 Z51 vert.

0RAAMaudio

A camber kit is nice insurance against losing your alignment while on the track which can really suck, especially if you do not realize it and dive into a corner with one wheel all messed up(camber changes effect toe a great deal, you could end up in a nasty spin and not really feel it coming on until to late)

At a bare minimum once you are dialed in mark the stock bolts and control arms so if it does slip you can move it back without having to redo the whole thing(it might end up off a little but still quite drivable)
Better to lose part of a session than the whole track day.

Rick