ITC Rabbit suspension help

[Eric Parham]

My ITC Scirocco had 650 lb/in front springs, no front bar, 425 rear springs, Shine rear bar. That was after many iterations with fronts between 400 and 750 and rears between 250 and 500. I found that different brands of springs were off up to 10%. I ended up with Hypercoils to reduce variables. My setup was on the hairy end of loose (even with new Hoosiers), and a real handful in the wet (400 rears or some sort of adjustability was wished for when the heavens let loose), but was definitely fastest that way. I almost always ran a VWM clutch-pack LSD or a Quaife TBD. As others have mentioned, a spool or welded changes everything (have one, only ran it once -- not my preferred style).

EDIT: I also had a very stiff cage, and Shine's spherical bearings front and rear.

[veeman]

Thanks for all the input!

Don't forget, if you decide to go with a spool or a welded front diff, that all the rest of your adjustments will go out the window.

Tim... Out of curiosity, how would the setup change with a welded diff? Would the car have to be softer in the front (that's what I'd heard) so that the car can grip / slip appropriately? Sounds like I need a "spring library" so I can check out different rates to try them out / swap with others!

Eric... your setup is what I had on paper initially to run, but now I'm considering going with something more "moderate" like Shine is recommending while keeping the rear bar.

Speaking of which, I looked at my rear bar again and it's pretty stout. According to the PO, it's a custom piece made by Walt Puckett...very similar to what he ran on his scirocco. It's a straight bar (probably around 23-25 mm) with square ends that's held in place by a block on either end end of the beam.

As for corner weights, I'll be figuring that out soon (we're working on redoing the cage now). I'd like to get the cross weights within about 3-5% of each other.

The spherical bearings are a must especially in rear which ends up with lots of slop without them. If you run new tires all the time setup for that... if you run 1 set of tires for many races then setup for this.

Beran... are you talking about the spherical cartridges Shine sells for the rear upper mounts? Right now the car just has urethane on them. The carrera's have a monoball style bottom mounting already...

You did not mentions what you have for camber adjustment or what toe specs you use.

Shooting from the hip here, I'd say that the Kumho's need about 2 degrees of camber in the front (need to verify) and I'm looking at running probably about 1/8 inch of toe out.
In the rear, I'm still debating. I've never really messed around with shims, but I'd like some camber in the rear (1.5 degrees?) along with a touch of toe in (1/16" inch?). Not sure I'll have time to experiment with the rear alignment before running the car. That may be too many variables right now.

Feel free to chime in with other ideas on alignment settings if you'd like.