Opinion on alignment settings

[widebody911]

I had my car re-aligned after my little 'oopsie' 'oopsie' at Blunderhill a couple weeks ago (hint: don't lift)

Turns out I lost an eccentric nut in the left rear (no jokes about me being a leftist eccentric nut - I already know that).

I asked the guy to set it up in a manner which I thought would be more aggressive. The car definitely drives differently now; haven't had it on the track yet in order to validate whether it's 'good' different or 'bad' different.

Front camber: -2.0
Rear camber: -2.3

Front toe: .02"
Rear toe: .06"

Caster: 6.3 degrees

Opinions?

[masraum]

Sounds pretty good from what I've heard, quite aggressive. Todd Serota recommends equal camber front and rear while most other people recommend about 1/2* less in the front. Sounds like you split the difference. I think aggressive is often around -1.5* front and -2* rear, max caster, and little to no toe in front with a tad more rear. Sounds like you've got that. With sticky tires you should be able to take advantage of those settings, I think you do run track rubber, don't you Thom?.

[petevb]

What type of tires are you running, and what is your track/ road driving split?

I runs significantly more camber than you've got, but that assumes sticky tires...

[cowtown]

Thom, where are you getting 911 alignments around here, and how much do they charge?

[widebody911]

Originally posted by cowtown
Thom, where are you getting 911 alignments around here, and how much do they charge?

OK Tire, Auburn & Myrtle $75

[Wil Ferch]

I just love ( not !) when toe is given in "inches". Just where is this measured? At the tire diameter? At the wheel rim edge? Same actual toe measured in these two places will give different numerical results.

Toe should be measured in minutes or degrees....that way it doesn't matter what the tire diameter is..or where along the tire diameter toe is measured...it remains the same "angle".

--Wil

[cowtown]

Originally posted by widebody911
OK Tire, Auburn & Myrtle $75

Thanks.

[Chuck Moreland]

Will, the inches measure is done on the rim. It's the difference between front and rear of the rim.

With basic setup equipment (ruler and strings), it's easier to talk distance instead of degrees. You do need to define the rim size for the measures to be meaningful.

For a track setup, I like to run about 1/8 inch total toe out up front, 15 inch rim. 0 to 1/6 total toe in at the rear. You'll find this gives quicker turn in.

Your camber is a decent starting setup. You really need to test with a tire pyrometer after a couple hot laps to get meaningful feedback on your setup. Without the pyrometer you are just shooting in the dark.

[RaceProEngineer]

Thom,

While we agree wholeheartedly with your HINT: Don't Lift , I am curious about your post. I know nothing of the incident to which you allude, and do not seem able to open and play the video link, but is it possible you went off because you were unable to turn in?

Stay with me for a moment -

It is highly unusual that one would lose an eccentric bolt from the spring plate, AND NOTHING ELSE, from an off-course excursion. Perhaps - just perhaps - the eccentric bolt (for toe or camber) came loose and/or fell out. (All the worse if you have an adjustable stabilizer at the rear, because that means it came loose too.)

Entering a turn, the rear becomes unstable, but the "seat-of-the-pants" symptom is that one can not turn into the corner. Natural reaction? Back off the throttle. Still no turn in? LIFT!! Now the (exceptionally) unstable rear end comes around violently.

Just a thought. Either way, we are glad you are back, with all 4 wheels pointed in the same direction (within a couple degrees).

Ed LoPresti
RacePro Engineering