Project: PBR-Built Z/28

[Lucky SOB]

Interesting point you bring up... sounds possible to me. The articulating ones aren't that much more are they? Plus UMI had that sale... had me lookin too

[DETROITMUSCLE]

I can't see the pic but I assume you have the poly ones, if that is the case they should "flex" more at the joint than a heim joint would. They are used to keep the sound at a minimum, the heim joint pieces seem to work better but come at the cost of being noisy, doesn't bother me at all.

[JoeliusZ28]

I can't see the pic but I assume you have the poly ones, if that is the case they should "flex" more at the joint than a heim joint would. They are used to keep the sound at a minimum, the heim joint pieces seem to work better but come at the cost of being noisy, doesn't bother me at all.

How would a solid poly busing flex more than a heim joint? Or are you talking about the mount? I have a rubber bushing on the body end of my LCAs, but I don't think that helps much at all... the LCA is a snug enough fit to still be a problem. I am worried about noise basically not at all, race car!

[DETROITMUSCLE]

the poly joint flexes under pressure where a heim joint is solid, it may swivel but once bolted up it shouldn't move. hats why mad man uses a heim joint in his torque arm design its the only way to truly have an instant center, if he used a poly bushing it would flex enough to move you IC around some on launch.

Hopefully Larry can help confirm this as its how I was understanding it.

[JoeliusZ28]

the poly joint flexes under pressure where a heim joint is solid, it may swivel but once bolted up it shouldn't move. hats why mad man uses a heim joint in his torque arm design its the only way to truly have an instant center, if he used a poly bushing it would flex enough to move you IC around some on launch.

Hopefully Larry can help confirm this as its how I was understanding it.

I think i see what you are saying, but as I understand it the poly bushing only has room to flex in the direction of acceleration and deceleration forces. However torsionally, the control arm itself is snug enough within the body/axle that articulation would be limited even if there were no bushing or bolt connected at all.

[DETROITMUSCLE]

I agree, but I don't see the lateral movement happening either. The heim joint LCAs I have come with spacers that fit just as tight as the stock LCAs the only way mine move are to adjust length no side to side or forward to rear movement.

[JoeliusZ28]

well i dont want forward or rearward movement ... I just want them to be able to twist freely, that is my concern with the BMRs I have now.

[DETROITMUSCLE]

put stock on then I don't think you want them to twist at all but then again I could be wrong.

[JoeliusZ28]

put stock on then I don't think you want them to twist at all but then again I could be wrong.

When cornering (which i will be doing) one side of the suspension is going to compress more than the other. They need to be able to twist in that scenario. For a drag setup they wouldnt need to.

[ThreeHonks]

Joel- the rod ended control arms are stiffer than poly. I had the same ones you have, except by UMI and just replaced mine with the double adjustable rod-ended version. I still think it wouldnt be a bad idea for you to have adjustable ones on there

[JoeliusZ28]

right, they are stiffer laterally which would be a good thing right? I seem to remember the adjustables on jeff's car had heim joints - meaning I could grab the control arm and twist it back and forth a certain amount, and that was more than what would be necessarily for axle articulation.

[DETROITMUSCLE]

they do clock slightly but I don't think thats articulation, would be interesting to mount a go pro or similar camera back there and see it all work.

[ThreeHonks]

yeah thats how a heim joint works. its way stiffer tho than a poly bushing.

I think you need to worry about that stock T/A first

[kammi10]

yeah thats how a heim joint works. its way stiffer tho than a poly bushing.

I think you need to worry about that stock T/A first

100% agree with that statement

[JoeliusZ28]

they do clock slightly but I don't think thats articulation

articulation is when the angle of the axle is not identical/parrallel with the bottom of the car, so yes thats what its for

And I know i need a torque arm... that is all planned out already just waiting for the right deal to come along.