Joined: Feb 2008
Location: Colorado Springs
One big source of confusion is always what you're measuring against, and why you're doing it.
The goal here is to have the pinion and the drive angle exactly the same during acceleration. For every degree that it's not the same, you lose power.
Remember that the drive line angle is the angle of the engine crankshaft/transmission main shaft. Not the drive shaft.
Under power, the pinion will rotate upward, as the front of the tires move downward. So, depending on your set up, you have to guess about how much the pinion will rotate. Baseline Suspensions provides some good guesses towards the top of the page, in red lettering.
OK, here's the tricky part. DO NOT measure the pinion angle against the horizon/ground. You measure it against the drive line (not drive shaft) angle. The driveline angle (AKA Power Angle) is usually 4-5*. It's easy to measure on the front of the harmonic balancer. The front of the engine points up.
Under acceleration, the front of the pinion should also point up the exact same amount - say 5*
For a stock suspension, expect the pinion to rotate up about 3-4*. That means the front of the pinion should point up 1-2* at rest. Under power, it will increase by 3-4*, and that gives you the recommended 4-5*. Which equals a 0* pinion angle.
Confused? Draw it out on a piece of paper, and it makes more sense.
'08 V6 Pony
'65 Monster FFR Cobra