Driveline angles
As I understand it, the engine/tranny tilt angle and the pinion angle should be equal, i.e. the two axis should be parallel and the U joint operating angles should not exceed 3 degrees ideally.
That all said, I see mopar enthusiasts using some pinion angle (preload?) to account for the rise of the pinion under load. That is, put the pinion angle a bit below parallel to the output shaft so that when it rises under load, it becomes parallel to the output shaft or close to it. Some in fact, determine this preload angle based on horse power, more hp means more preload angle (apparently this is derived from empirical observations).
OK, so I measured my output shaft angle and the engine/tranny is sloped downward (from front to back) 3.4 degrees. The pinion is sloped downward (from front to back) .6 degrees. My driveshaft slopes downward 2 degrees. Using Spicer's driveline operating angle calculator, see pic below, gives me equal operating angles at each U joint of 1.4 degrees. This seems fine, I don't have any vibrations of which I'm aware. My inclination is to leave it alone, but....
Questions:
1. should I shim the axle regardless, say with a 2.5 degree shim so that the output shaft and pinion are parallel at rest?
2. My engine puts out 375 hp at the crank, does that change your answer to question 1?
As I understand it, the engine/tranny tilt angle and the pinion angle should be equal, i.e. the two axis should be parallel and the U joint operating angles should not exceed 3 degrees ideally.
That all said, I see mopar enthusiasts using some pinion angle (preload?) to account for the rise of the pinion under load. That is, put the pinion angle a bit below parallel to the output shaft so that when it rises under load, it becomes parallel to the output shaft or close to it. Some in fact, determine this preload angle based on horse power, more hp means more preload angle (apparently this is derived from empirical observations).
OK, so I measured my output shaft angle and the engine/tranny is sloped downward (from front to back) 3.4 degrees. The pinion is sloped downward (from front to back) .6 degrees. My driveshaft slopes downward 2 degrees. Using Spicer's driveline operating angle calculator, see pic below, gives me equal operating angles at each U joint of 1.4 degrees. This seems fine, I don't have any vibrations of which I'm aware. My inclination is to leave it alone, but....
Questions:
1. should I shim the axle regardless, say with a 2.5 degree shim so that the output shaft and pinion are parallel at rest?
2. My engine puts out 375 hp at the crank, does that change your answer to question 1?