Bump steer question

[jaybee]

I've got a pretty good handle on how bump steer works on conventional center link systems and racks which have tie rods which come off the ends of the rack. I'm a little surprised to find out I can't find much on how center take off racks like Chevy Cavalier or Dodge Intrepid affect bump steer. Any thoughts on that?

[jaybee]

OK, just to close this out, here's what I was able to find out.

As far as I can tell the key to using a center take off rack, like a Cavalier rack, with very long tie rod ends is to tune the geometry so the swing of the tie rod conforms most closely with the suspension arms in the actual range of suspension travel. That's really "workable" rather than correct, but there are compromises in all engineering. There's a diagram here to identify that.  https://www.fordmuscleforums.com/threads/another-crazy-idea-honda-civic-center-take-off-unisteer-rack-pinion.560058/

Sure looks like the better solution to spread the tie rods apart to mimic the stock locations, or improve slightly if you want to do the extra work of checking and tuning bump steer.
http://mmb.maverick.to/threads/best-case-for-a-stock-front-end.97004/

https://www.stangnet.com/mustang-forums/threads/j-car-rack-and-pinion.479599/

[enjenjo]

Here is another way to do it I have used in the past with good results. I just make up a spreader bar to space the inner tie rod ends in the correct place.

[jaybee]

I think that's the right answer. How do you seat the inner ball joints in the spreader bar?

Here's my thinking. The Cavalier rack can be a little problematical in a compact/midsized Ford because the front mount tie rods push the rack way back by the bellhousing. That's where headers want to live and the steering shaft angles push the limits.

Since the pinion shaft is a lot more vertical than it is in a Cavalier the tie rod bolts move to the bottom and you can mount a bracket that'll put the spreader bar to the rear of the rack, but that moves the rack up into the area where the the belly bar lives. That's technically an optional part of the car, but it adds structural strength to a car that needs it. Racing Boss 302s even put a gusset on that bar to keep it from bending and tie in the lower control arm bolt. That area of the car sort of hangs out in space and it does flex.

The solution could be a C-shaped crossmember, open to the back, with enough height and depth to give it strength and make room for the rack to push into that space from the back.