Project: PBR-Built Z/28

[hoogiesngrinderz]

I can find one or scan the info, if I can find it.

Ideally, the pinion angle should match the transmission output shaft angle. This is supposed to counteract any forces on the driveshaft

[JoeliusZ28]

I can find one or scan the info, if I can find it.

Ideally, the pinion angle should match the transmission output shaft angle. This is supposed to counteract any forces on the driveshaft

Gotcha, thanks for putting that in layman's terms, that makes sense to me. I'll take a look at it tomorrow and see where its at.

[birdie2000]

IIRC UMI gives the same instructions as BMR.

http://www.bmrsuspension.com/siteart/install/TA001.pdf

Some people will argue against this method, but it's a starting point if nothing else.

[bri2203]

I can find one or scan the info, if I can find it.

Ideally, the pinion angle should match the transmission output shaft angle. This is supposed to counteract any forces on the driveshaft

What he said

[JoeliusZ28]

IIRC UMI gives the same instructions as BMR.

http://www.bmrsuspension.com/siteart/install/TA001.pdf

Some people will argue against this method, but it's a starting point if nothing else.

Based on that I'd have to agree with what Michael recommended above. Good stuff. I'm thinking this isn't that critical if its slightly off. Heck, my rear axle was twisting around in stretched torque arm bolt holes for a while earlier this season ... then again, that did kill the u-joint.

[c0ncEpT]

I personally like to measure the pinion angle. Not the driveline angle. The angle of the driveshaft does nothing for me. I like to set the pinion angle to a -1.5 to -2 degrees. Meaning the diff should be pointing 1.5 o 2 degrees towards the ground not the sky. This is how MADMAN does it and its worked great for me.

[birdie2000]

Here's more info to further complicate the issue, and the reason why some people like to measure the trans-output shaft.

http://www.markwilliams.com/driveshafttech.aspx

[hoogiesngrinderz]

I personally like to measure the pinion angle. Not the driveline angle. The angle of the driveshaft does nothing for me. I like to set the pinion angle to a -1.5 to -2 degrees. Meaning the diff should be pointing 1.5 o 2 degrees towards the ground not the sky. This is how MADMAN does it and its worked great for me.

Depends on the car. I think we had this discussion before.

But overall, this isn't a bad way to go about setting driveline angles. There are so many variables that it differs from vehicle to vehicle

[JoeliusZ28]

So per the madman method I would already be in spec. I could always use both methods and meet in the middle.

[c0ncEpT]

Yes. His method works. We accidently set Jeffs pinion angle to +2 once. The car wouldnt get out of its own way. Set it back to -2 and it went 1.45 60' next time out yanking both wheels.

[1BADAIR]

my car wont move if i measure off the driveshaft. pinion to subframe connectors is how i do it

[JoeliusZ28]

Yes. His method works. We accidently set Jeffs pinion angle to +2 once. The car wouldnt get out of its own way. Set it back to -2 and it went 1.45 60' next time out yanking both wheels.

my car wont move if i measure off the driveshaft. pinion to subframe connectors is how i do it

incredible that a couple degrees angle in a u-joint eats up that much energy

[hoogiesngrinderz]

incredible that a couple degrees angle in a u-joint eats up that much energy

I'd like to be corrected if I'm wrong, but angle helps with planting the rear....right?

Pinion down 2* with a DS up ~2* = 4*
Pinion up 2* with a DS up ~2* = 0*
Then add in the torsional forces...

Meh..I'm going to have to measure the 98 (all stock, stock height) vs my 89 (lowered, pinion 1* down, DS 1.5* up?). I'm tired

[JoeliusZ28]

does it? Seems like the same forces would be applied to the torque arm and control arms regardless of pinion angle... Is there something im missing?

[hoogiesngrinderz]

Depends on the purpose of the car. Drag, auto-x, street, and so on. Stock torque arms will allow flex, stock LCA bushings will cause flex, power levels will create different body flex.

The angles will cause changes on where/how the forces are applied.