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1993 RMW, 1996 RMW, 1992 OCC
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Discussion Starter · #1 · (Edited)
These B-bodies have a lot of dive under braking. Especially the wagons with their higher CG.

I've got new upper and lower control arms waiting to be installed in my '96 RMW, and the uppers have added caster, tall ball joints, Delrin bushings and offset cross shafts. Would it also be beneficial to move the rear mounting hole downward to add a little more anti-dive? I'm not looking for flat braking here, I still want decent articulation up front under braking. But a little less dive under hard braking sure would be nice.

If so, how much change would be advisable? I can't find front suspension dimensions anywhere for these cars so it's difficult to enter figures into calculators to figure out how much effect 1/8" vs 3/8" change would have... but I assume some people who race B-bodies would have advice.
 

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1993 RMW, 1996 RMW, 1992 OCC
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Discussion Starter · #2 · (Edited)
Just to clarify, I'll be replacing the upper control arm mounting studs with modified ARP wheel studs that have a larger knurl diameter, which will require me to drill out the mounting holes. This allows me to shift the mounting holes up or down when I drill them out. I can adjust up to 3/16" on each hole, for a total of 3/8" if I move both the front and rear mounting studs in opposite directions (one up, one down)
 

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You can check late 50s Chrysler products for anti dive geometry. You can also move the front up at the same time. Since moving the front up does not change the orientation of the inner tierod end's relationship to the lower arm bushing, because it is a direct line from the back and front lower bushings and through the rotational center of the inner tie rod (subject to manufacturing tolerances).

There is a tiny bit of anti-dive built into the B bodies, but not much.

When drilling, make sure the drill does not use the original hole as a pilot hole, and just make it larger. I use a dremel, and a 1/8" carbide end mill to make holes larger. You may have to make the upper arm shaft holes larger too, or are the studs the same size thread as the OEM ones?

3/8 inches is not a tremendous difference, but it is better than none. I am curious as to how well it works.
 
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1993 RMW, 1996 RMW, 1992 OCC
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Discussion Starter · #4 ·
The studs are the same thread diameter as stock, they just have a bigger knurled shoulder. I used them on my 77 Trans Am (without changing the height of the mounting holes)


 

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1993 RMW, 1996 RMW, 1992 OCC
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Discussion Starter · #5 ·
From my quick math, a total of +/- 3/8" difference would be about 2.75 degrees of added inclination. But without knowing where the CG is, it's hard to know how big a difference that would make to anti-dive. I really wish I could get all the suspension geometry measurements to enter into a suspension analyzer software. With how long people have been building Pro-Touring 2nd gen F-bodies, you'd think these numbers would be readily available, but I can't find them.
 

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The CG will not have all that much affect. Chrysler cars are similar, so if you look at their suspension, it should give you a rough idea of what you will get. Chrysler used to tie a porcelain cup, close to the ground, on the bumpers of their cars, then slam the brakes on at speed. the cups did not hit the ground, Anti dive is a relationship between the upper and lower arm angles.

 
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