best suspension modelling software?

[xlr8tr]

Originally Posted by strictlypersonl

Mark,
Unless you are planning on ripping all the attachment points off the chassis, the most important factor for stable driving is the bump-steer curve. That can be measured with relatively cheap/simple tools. Once determined, it's not too hard (relatively) to change the steering gear position and tie-rod length.

If you buy that software, you will have to spend 10's of hours measuring your attachment points, etc. A nice intellectual exercise, but of little real use - your car is already built.

I agree with you 100%- but inmy case the car was built POORLY. I definitely will be moving suspension points, steering rack ect. Just a couple of examples I have figured out so far from reading/researching:

1) steering rack is about 4 INCHES too wide: from what I have read, to minimize bump steer the sterring rack inner pivot points are supposed be on the imaginary line between the upper and lower A arm inner suspension pivots, and they are INCHES off on each side. The way is is now, any bump steer correction will give perfect bump steer at ride height +/- about 1/4" of travel, then all hell breaks loose.

2) the imaginary lines created by the upper and lower rear 4 link arms are supposed to cross somewhere close to the front of the car, but they actually point BACKWARDS and no way to adjust that out

3) lower A arms at ride height are nowhere near level, they point up about 2" from chassis to where they attach to the uprights. Drop spindles will fix that, but then i have no idea what happens to camber curve etc.

4) I have the old school lower "A" arms that have the strut rod rear arm that connects to the chassis- problem with that is, it severly limits steering angle as tire rubs on the strut arm, sterring radius is probably worse than my 3/4 ton diesl pickup so no auto X possible, I'd have to do 3 point turns in the hairpins

Sooo, bunch of stuff to chop out and re-do, my son is a metal fabricator so I have free skills to use but if I'm re-doing it, I want to do it right. I'd like to auto-X or something occasionally. Impossible now.

[strictlypersonl]

Originally Posted by xlr8tr

I agree with you 100%- but inmy case the car was built POORLY. I definitely will be moving suspension points, steering rack ect. Just a couple of examples I have figured out so far from reading/researching:

1) steering rack is about 4 INCHES too wide: from what I have read, to minimize bump steer the steering rack inner pivot points are supposed be on the imaginary line between the upper and lower A arm inner suspension pivots, and they are INCHES off on each side. The way is is now, any bump steer correction will give perfect bump steer at ride height +/- about 1/4" of travel, then all hell breaks loose.

What length are you looking for?

2) the imaginary lines created by the upper and lower rear 4 link arms are supposed to cross somewhere close to the front of the car, but they actually point BACKWARDS and no way to adjust that out

Interesting. In a bad way. Usually the fix is to weld taller brackets on the rear end housing.

3) lower A arms at ride height are nowhere near level, they point up about 2" from chassis to where they attach to the uprights. Drop spindles will fix that, but then i have no idea what happens to camber curve etc.

That would depend on whether the distance between the top and bottom ball joint changes. Usually dropped spindles keep the original distance.