pinion angle

just back halfed a 74 duster for a fellow drag racer . narrowed 8 3/4 32in by 14in tires.i have set pionion angles before but this is the first time that the pinion center line is higher than the trans center line ,the pinion angle is 5degs neg or in the nose down position the drive shaft angle is 2deg positive or up position because the trans is 3/4in lower than level center of the pinion . this is a ladder bar suspension so is the pinion angle neg3degs or am i reading this wrong. thanks:confused:

i look at the link,if i read it right the engine angle and the pinion angle are the important ones not the drive shaft angle.so in my case the engine is at neg3degs and the pinion is neg5degs so that totals neg8degs.so the trans centerline being below the pinion centerline does not affect the total angle.

You'll be just fine.

On a ladder bar chassis with very little pinion angle change on acceleration, don't you think 8 degrees is a little excessive? Why not swing the pinion upwards a bit - maybe as far as only 1 degree down?

How well the rear suspension controls the position of the rearend is the most critical issue that determines how much pinion angle will be needed. Some types of rear suspensions offer more control than others and require different angles. a ladder-bar suspension normally requires ½ degree of pinion angle, a four-link requires 1-2½ degrees, and a leaf-spring suspension requires up to 6 to 7 degrees. In all examples, we’re talking about negative pinion angle, i.e., the pinion is nose-down in relation to the driveshaft.

thanks for the reply,im just trying to get this straight that the pos2degs i have at the driveshaft does not come into play when doing the math, i always thought that driveshaft angle was to be 0deg to 2deg negative but never positive is that correct or not.thanks:)

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Originally Posted by terrylittlejohn

thanks for the reply,im just trying to get this straight that the pos2degs i have at the driveshaft does not come into play when doing the math, i always thought that driveshaft angle was to be 0deg to 2deg negative but never positive is that correct or not.thanks:)

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thats close enough, if you were racing, the idea would be to have the angle set so when you went throught the speed traps at WOT under full power the pinion angle would be 0 degrees. it takes less HP to turn it at 0 degree. i'd set the pinion angle at 2 to 5 neg. degrees and let it ride. :eek:

thanks again it was a interesting read, the key word here was simple,in my case the pos2degs at the driveshaft +the neg5degs gives me neg3degs pinion angle this is close enough for a 450hp small block mopar.:)

thanks mike that sounds good to:)