Best pinion angle

**shownomercy** · 10-09-2014, 10:56 PM

You will have some noisy ass driveline stuff if its severely off.

**firebird_1995** · 10-10-2014, 12:13 AM

Originally Posted by jahajazz

Dont want to hijack, but is pinion preload only applicable for dragstrip launching? I have read that for minimizing driveline vibration, the best setup is setting the pinion angle to the opposite of the trans output angle, so that he u-joints are in phase?

Well, from what I've READ (not much real world experience here so if im off, someone please correct me) the common -2ish preload (measured with the suspension sitting stationary under full weight with driver in seat) is a benchmark because when the car launches, the pinion rolls upward under load and (should) put the pinion to driveshaft angle at zero, where the least amount of energy is being lost due to misalignment in the u joint. This is great in a racing environment where you want to minimize driveline loss.
From a normal driving condition situation, a u joint should have at least 1° of misalignment to keep the bearings in the u joint cups from wearing improperly. It is considered "balanced" when the joints have equal but opposing angles. Meaning if your front u joint, measured in the difference between the trans yoke and top of driveshaft is +2° then the rear joint should have -2° measured between pinion yoke and top of driveshaft. This would be considered to be in perfect balance. The industry standard seems to call for no more than 3.5° for longevity with 5° becoming a reason for concern. From the factory, most gm crankshaft centerlines are between -3 and -4°. The angle of the driveshaft depends on the depends on the length of the driveshaft. If you have a shorter wheelbase and longer transmission, you're going to have a shorter driveshaft and have to pay closer attention to your angles.

http://www.hotrodhotline.com/md/html..._harmonics.php

Maybe I said that right

**SSlowBoat** · 10-10-2014, 12:21 PM

^what he said

**Camaro96** · 11-08-2014, 11:45 AM

firebird_95 well said.

**Wilburbeest** · 01-14-2015, 08:05 PM

Originally Posted by firebird_1995

Well, from what I've READ (not much real world experience here so if im off, someone please correct me) the common -2ish preload (measured with the suspension sitting stationary under full weight with driver in seat) is a benchmark because when the car launches, the pinion rolls upward under load and (should) put the pinion to driveshaft angle at zero, where the least amount of energy is being lost due to misalignment in the u joint. This is great in a racing environment where you want to minimize driveline loss.
From a normal driving condition situation, a u joint should have at least 1° of misalignment to keep the bearings in the u joint cups from wearing improperly. It is considered "balanced" when the joints have equal but opposing angles. Meaning if your front u joint, measured in the difference between the trans yoke and top of driveshaft is +2° then the rear joint should have -2° measured between pinion yoke and top of driveshaft. This would be considered to be in perfect balance. The industry standard seems to call for no more than 3.5° for longevity with 5° becoming a reason for concern. From the factory, most gm crankshaft centerlines are between -3 and -4°. The angle of the driveshaft depends on the depends on the length of the driveshaft. If you have a shorter wheelbase and longer transmission, you're going to have a shorter driveshaft and have to pay closer attention to your angles.

http://www.hotrodhotline.com/md/html..._harmonics.php

Maybe I said that right

I have absolutely nothing to add to this. F$%^ing top shelf post.