IRS suspension alignment settings

[Jim Nilsen]

I keep going over the alignment specs from Vette Brakes website and still am not sure what settings to use. I am currently running at least -3 degrees in the rear and probably -1 to -2 in the front and am getting real good tire wear so far. The toe is feeling good but what it is exactly is still to be a mystery? I set it at just a tad in for starters. I did the best I could with a tape measure and it tracks real well on the street and over bumps. I can let go of the wheel and it goes straight, turn in is locked on like a cruise missle. When I want to turn it goes now with no delays and is right on to the corners.

I am looking for any input on what might be the best settings that others have experienced? I keep thinking I will go aggressive on the settings so I can get even tire wear with the hard cornering that is planned on. I keep telling myself that the same camber up front as in back would be good but normal specs usually have 1/2 as much in the rear.

So any of you who have or have had an IRS setup on a car, what was your favorite settings?

Thanks for any input.

[hotrdblder]

-1 to -1.5 is general in the rear, on the front anything more the -1.5 you will chew tires up on the street, however at the track you would want to run -2.0 to -3.0 depending on track.
you really need to run the car on the track, check tire temps etc and tune alignment from there.
on toe, i would use 1/8th toe out for track, with caster near 7 degrees

[Jim Nilsen]

-1 to -1.5 is general in the rear, on the front anything more the -1.5 you will chew tires up on the street, however at the track you would want to run -2.0 to -3.0 depending on track.
you really need to run the car on the track, check tire temps etc and tune alignment from there.
on toe, i would use 1/8th toe out for track, with caster near 7 degrees

Thanks for the input, I think I will go with -1 in the rear and -1 up front to give me a base start and add more if needed. The caster at 6 seems like a good place to start also.

Do you run the same amount of toe front and back?

Thanks again

[David Pozzi]

Jim,
Glad to hear you have it running!
I don't have a good suggestion for IRS, but I'd visit the Corvette forums and see what they are using on open track cars. The more neg camber you run, the less toe-in you need.