Coilover question

[dipren443]

I am in the process of installing coilovers on my 73 Z/28. I am modding my frame and my newly purchased Hotchkis lower control arms.

I am trying to decide... Do I use bearings or bushings in the coil overs?

Pics for clicks!

[dipren443]

I will add a little more info. The car will see mostly spirited driving on the street. Definitely some autocross and open track days as well.

I am leaning towards a bushing control arm side and a COM8 bearing frame side. Any reason to do otherwise??

[Randy67]

I would lean toward the bearings, a bit more precise response, i.e. no bushing give/deflection.

While you're at it, you could do the 2nd gen mod (similar to 1st gen Guldstrand mod) that the Trans-Am racers did. I believe they lowered the control arm mount down 3/4" which brought the roll center up some and lowered the rear bolt hole 3/8" for some more anti-dive. The info is out there, but I can't locate it right now. I may have it at home. If so I will get it to you.

[dipren443]

I would lean toward the bearings, a bit more precise response, i.e. no bushing give/deflection.

While you're at it, you could do the 2nd gen mod (similar to 1st gen Guldstrand mod) that the Trans-Am racers did. I believe they lowered the control arm mount down 3/4" which brought the roll center up some and lowered the rear bolt hole 3/8" for some more anti-dive. The info is out there, but I can't locate it right now. I may have it at home. If so I will get it to you.

I actually have the Herb Adams (I think) booklet outlining all of those mods. I was debating those mods, though I am also using Hotchkis control arms, so not sure if they are necessary.

[Randy67]

Unless the Hotchkis arms have taller upper ball joints, they won't change the roll center, but they should add needed caster though. Won't hurt to do the mod with those arms, every bit helps they say. SC&C uses a taller upper ball joint to get the same effect (except for the anti-dive part).