Camber set up for six, Need some help Options

[sixaddict]

Doing some "work" to get more negative camber up front ...but now trying to decide entirre set up....Been so long since had this done I am forgetting.
RA1, 16 X 225 50 w/ 7.5" wheels front
Ditto 16 x 225 45 w/ 8.5 rear
Shooting for 2 1/2 negative up front
What should I do @ the rear.
Mainly DE/track but some autocrossing.
Prefer to compromise ax set-up as opposed to track. 2.7 at this time if it matters.
Thank for the help
Terry

[brilliantrot]

Negative camber settings are a function of driver aggression, tire construction, and the rest of the suspension set up. When I was running my relatively softly sprung 914-4 on Hoosiers, I had -4 degrees of front camber and tire temps said I needed more. Keeping the car flatter would have reduced the need for more camber.

For the rear, I pulled all the shims out and ran it. At the ride height I was at, that was 2.5 degrees in the rear and tire temps indicated that was about right.

My car was stock front T-bars, 22mm front sway bar set most of the way stiff, 200lb/in rear springs and 225/45/15s all the way around.

[J P Stein]

Negative camber settings are a function of driver aggression........

I detect some B Roberts BS here.

Testing by GRM some years back showed that camber in excess of -3.5 degrees resulted in loss of braking performance to the detriment of AX times.... In other words, the test drivers started going slower. Those drivers were no slouches.

[brilliantrot]

Negative camber settings are a function of driver aggression........

I detect some B Roberts BS here.

Testing by GRM some years back showed that camber in excess of -3.5 degrees resulted in loss of braking performance to the detriment of AX times.... In other words, the test drivers started going slower. Those drivers were no slouches.

I would say depends upon the car, track, and the tires. The article that I remember from GRM about camber testing was in a Mini Cooper S around Streets of Willow which isn't really a fair comparison to a 914 at AX. Braking does suffer at much over -2.5 in my experience but because I ran 4 front calipers and an ajustable pressure limiting valve I could still set it up to lock the rears at the same time as the front or a little before and trail brake heavily to help scrub a little more speed. Anyone who has driven a GoKart knows you can get by with out front brakes if you don't mind sliding a bit and understand the limitations.

Also to support my point, the 2009 GT3 Cup Service Manuel I have suggests starting at -4 degrees of camber in the front and they are neither softly sprung or have a worse camber curve than a 914. A 2009 Cup isn't a great comparison but probably is about as good a data point as a Mini Cooper is.

There are few absolutes in racing as every car and driving style are all a little different so none of us can really say anything more than what we have found on our cars. On my current 911 I have -2.8 in the front and that seems to be enough as I don't lean on the front tires with it quite as much as I do in a mid engined car.