Whats the best way to set this?
Measure pinion angle only?
Minus the pinion from the driveshaft angle?

I'm setting the car up for drag racing. Thanks for the help.

 

Set the pinion angle in relation to the ground. The driveshaft is irrelevant. Set your angle finder on the pinion yoke. Set it 2 to 3 degrees down.

 

is there a difference b/w teh settings for the "long" tq arm and the "short" arms like yours Madman/BMR trak pak?

 

No. The pinion angle is the same. Now this number is a good starting point. Every car might want a little different.

 

I assume for this to work the car must be sitting perfectly level?

 

Would that be the same as putting the angle finder on the little fin on the rearend that i've heard is supposed to be even with the pinion? Or am I not even thinking of the right thing?

 

The car needs to sitting as it would at the starting line. I only use the pinion yoke to measure off of.

 

OK, I set mine according to BMR instructions, and I think their instructions are either dead wrong or they are confusing.

Here are their instructions, they say to measure both the driveshaft and the mounting plate:
---------------------------------
Set pinion angle using the following method:

· Make sure the rear end is loaded by either setting the car on the ground or letting the car rest on jack stands positioned under the rear axle.


· Place angle finder on the driveshaft and record the angle. Now place the angle finder on the rear end torque arm mounting plate and record the angle.

· Subtracting one angle from the other results in your pinion angle.(Ex: -6 rear end angle subtracted from +4 driveshaft angle = -2 degrees)

· Turn adjuster to achieve the desired angle.

· As a starting point, most F-Bodies seem to like the following initial settings: Automatics: 1-2 degrees negative, Manuals: 2-3 degrees negative
-------------------------------------


These are the instructions I was given with the damn Torque Arm! I followed the instructions and the car was making a nasty sound, vibrations, and just didnt feel right. So I took the car out to a weekly meet on Friday and I was asking around about it and one guy told me not to worry about the driveshaft, just set the rear end down negative 2-3*. And I told him about the instructions and he just said that seems way off.

Anyway, he finally said, "this is the way MADMAN says to do it".

So I came on here and searched for a relevant post...

Is this BMR's fuckup or what? I need to call them up. Now that I know more about this stuff I can tell that the way they had me set it up is completely wrong. I am at -6 pinion angle lol

 

Here....
http://www.carcraft.com/howto/91758/

Quote from that article.....
"Pro Stock chassis builder Jerry Bickel assures us, “there is no mystery to pinion angle.” Setting the pinion angle is the final step in driveline alignment. The goal is to create a straight line from the back of the crankshaft through the transmission, driveshaft, and the pinion of the differential—under load. Due to the tendency of the pinion to rise under load, some angle must be present at rest."


Our torque arm acts similar to a ladder bar setup except that we don't usually have solid mounts. So you want 2-3 deg. negative as BMR suggested, however their instructions on how to get there are f-'d up.

Here, this is good too.
http://www.baselinesuspensions.com/info/pinionangle.htm

 

Thats for sure! I will try to get a scan of the sheet...

 

I always set my pinion angle according to the crankshaft centerlineand the angle of the crankshaft as it sits in the car.

 

So you just place the finder on the pinion yoke, and make sure its showing negative 2 or 3? Is that all you measure? Do you have to remove the driveshaft.

 

I've looked at all of these post but I though you measure it as if the driveshaft and pinion were straight (measuring with the angle finder) then turning down the rear to get your 2,3,4,0r whatever degrees differance in the two to achieve your negetive angle on the rear so when your on the gas the rear and driveshaft are straight not robbing you of any power due to angles and bind.

 

I'm not trying to put you down. But how does that work ? I thought the idea was to get the driveshaft as straight as possible when your on the gas. How does that work on cars that are lowered or ones with tall tires in the front . Wouldn't that be different on each of them cause with the front of the car up or down that changes the driveshaft angle. Maybe you could explain a little bit so I could see where your coming from.

 

The drive shaft vs pinion is called "driveline angle" How would you set pinion angle with a car that the rearend is higher than the trans output and the driveshaft runs UPHILL to the pinion???

Set your pinion without the driveshaft to 2.5/3.0 and go racing the driveline angle wont give you any problems.

 

So for those of that us that dont know as much about driveline angles, does that mean I need to take of the driveshaft, then place the angle finder on the yoke?

 

You can do it that way.

 

Ok. I now see that there is adifference between "Driveline angle" and Pinion angle. Is there a Good Driveline angle to shoot for? or is it best to just shot for the Pinion angle and call it a day?

 

The way I understand it is that you do not have to remove the driveshaft. Simply put the angle finder on the bottom of the torque arm mounting plate and measure your 1 to 3 degrees downward angle. Downward meaning that the front of the rear end is arched downward.

 

Thats the way I do it, although it may be recommended to verify that plate is 90deg from the actual yoke angle. I'm pretty sure its supposed to be, but machining operations may not be as 'dead nut' as expected.

Right now my "pinion" angle is zero in relation to level ground at ride height. My "driveline" angle is 3, so if I move the "pinion" angle to 3 also that would make this "driveline" angle 6 no load.....? But.....I'm thinking that the driveline angle would follow the pinion angle somewhat during adjustment since it will move also, while its 3 degrees now, with the pinion itself at 3 down it may only change 1/2 the difference, possibly 4.5 "DL" degrees instead. I know I'm probably overcomplicating things.