Calling BioMax - rack & pinion tech?

Max I'm curious to know if you can shed some knowledge on proper rack and pinion placement and geometry? Perhaps a nice diagram?

Thanks for the help,Nick

Rack or box, the geometry is addressed the same way for both. The only difference that we are concerned about here is that the rack houses the inner tierods, where the box drives a center link with the inner tierod mounts on it.

Proper rack placement depends on where the inner tierods should be. The biggest problem with racks is that the distance between the inner tierods is set by the rack so you need to order a rack with the right inner tierod width. Height placement needs to be calculated with this diagram



and front to rear placement needs to be calculated for ackermann. (See the sticky)

Racks can really be a pain to get in the right spot and/or find the reight width. The only rack car I have ever done was the Chevelle in my profile and I had some fun finding the right rack for my aplication.

When ordering a new rack from Unisteer, would using the original distance between the inner tie rods on the centerlink for the inner rack tie rod spacing be acceptable?

Is there a possibility to improve upon the geometry beyond what GM intended for daily driving?

It depends on which GM vehicle. The S-10 has a small amount of built in anti-ackermann as well as some toe out in bump. They did this to create under-steer (it's much safer to have a vehicle that under-steers than one that over-steers) So for a daily driver that might have expensive tires on it, from that stand point...

Yes you can improve on factory GM geometry.

I've built a front subframe for my Astro van based on 77-96 B-body (caprice) dimensions and geometry. The steering is one of the last pieces needing to be addressed.

What should I look at to be improved? Toe change should be as minimal as possible being that the vehicle is "bodydropped" and 22" tires aren't as disposable as they could be.

I once had an S-10 bodydropped on 20's and the toe change from full lift to drop was very extreme, I'd like to avoid this as much as can be helped.

I'm not sure if that front suspension has the same issues as the s-10. The best thing that I would suggest to do would be to cycle the suspension whith the stock steering installed and find out what flaws it has. Tune to Win by Carroll Smith addresses slmost all of the possible steering issues that you might encounter and also explains how to test for them. From there you can install a rack with the appropriate changes.