ORIGINAL: PRO50SC

Not a good way to get responses to your problems!!


Maybe tyhis will help.



SETTING PINION ANGLE



Need more traction out of your Steed? Try adjusting your pinion angle. As suspension gurus tell us, pinion angle is critical under hard launching conditions. The action/reaction tendencies of the Mustang's pseudo four-link suspension creates a pretty significant amount of axle rotation under hard launches. As the tires bite, the pinion's reaction is to rotate upwards towards the pinion snubber. This tends to unload the tires and create wheel hop. The optimum power transfer would be if you could get your transmission, driveshaft and pinion to form a perfectly straight line as shown in the top figure. Unfortunately, with articulating suspension, varying ride heights and other geometric considerations its highly unlikely that you'll ever wind up with that perfect alignment. When I'd measure my geometry with Megabite Jrs. lower control arms and stock upper control arms, my car had the pinion pointing upwards 2.5 degrees and the driveshaft pointing upwards 1.5 degrees (both running uphill when looking from the back of the car forward). I've tried to show this in the middle drawing. Under hard launches, the pinion will have a tendency to rotate 3 to 4 degrees upwards which was leaving my pinion pointing to the sky (well almost). I tried to limit this somewhat with a Competition Engineering adjustable pinion snubber (see photo here) but the initial upward orientation still wasn't what I needed. So then I installed a set of Unlimited Performance's double-adjustable uppers (see photo here). The adjustable uppers allow you to shorten (or lengthen) the upper control arm, which changes the initial pinion angle. By shortening the UCA length, I was able to get the pinion pointing about 2.0 degrees downward with the driveshaft following it to about 2.0 upward. This provides a total difference between the two of about 4.0 degrees downward (negative) pinion angle. Under hard launches, if the pinion rotates 3 to 4 degrees upward, it should just about straighten the driveline for maximum bite and power transfer.





So how do you measure the angles? I built four wood blocks of 2-by-12 lumber, two pieces thick by about 15 inches long. This way I can get the car far enough up in the air to crawl under and make the measurements and adjustments while still maintaining the normal ride height, weight distribution and driveline geometry. I bought a simple angle finder at Sears for about $10 that gives angles to the nearest 1/2 degree. To measure the driveshaft angle, simply place the angle finder on a straight and smooth portion of the driveshaft. To measure the pinion angle, I measure off the side of the pinion companion flange. There's enough flatness to the edge that if you're careful you can get a good read off the angle finder. Click here for an exploded view of the pinion and driveshaft measurement.



If you have converted your rear suspension to all spherical bearings instead of rubber or poly bushings, the deflection under load is going to be much, much less. In this situation, you want to set your pinion angle as neutral as possible with the car at its normal ride height.

ORIGINAL: PRO50SC

Get THESE. I know a few ppl running them and like them.