what pinion angle for the street?

what is the best pinion angle for street racing for the best traction at off the line in a stock susp. coupe.

pinion angle is all about keeping the ujoints happy, nothing to do with traction.

i have to disagree, pinion angle plays a factor in traction. every race chassis shop in the country sets pinion angle. Door Slammers The Chassis Book (which is must read for every drag racer imo) explains it very well. my mustang is set to -2

if you move the "pinion angle" and that only, there is no effect on cg etc, only now the drveline is in a different spot. If that makes any sense.

Take my ladder bar for example. I can move the bars to a different hole, this does change pinion angle, but its not the pinion angle that affects the reaction, but the change in the bars.

I do a poor job of explaining it, but in my head it all makes perfect sense lol.

Possibly someone with a better vocabulary will come along and explain better.

i have to disagree, pinion angle plays a factor in traction. every race chassis shop in the country sets pinion angle. Door Slammers The Chassis Book (which is must read for every drag racer imo) explains it very well. my mustang is set to -2

I agree, if the suspenstion is binding then it will effect the launch . Also setting the pinion angle goes buy what kind of bushings you use . If you have all rubber bushings then you will need more negative pinion angle becuese there is more movment . If you have metal bushing you won't need hardly any negative angle because there isen't much movment

You want the outputshaft on the trans and the pinion on the straightest line of sight possible when the car is under power, this will offer the least amount of power rob from the ujoints. Some suspension types pinion angle may not able to be adjusted individually, in this case pinion angle will play a role. I can change my pinion angle without affecting rear sus geometryon my setup, in this case I fail to see how pinion angle in itself has an effect. I have about -2 myself with the car in its rest position and me in the car fully wet.




I made the post above as the guest, dont know how that happened but might explain all the spam, this forum needs fixed lol.

Jon's initial response is correct because in GT's opening question he asked what was the "best pinion angle" for "best traction"....there is no such thing.

Kyle, yes chassis shops/chassis people do set pinion angle. But as Jon said it's to set the U-joint(s) operating angles to keep the driveshaft "happy" in it's intended operating environment (drag use only or street/highway use), and the type of chassis/suspension used (stock, mini-tub, back-half, full chassis). Using pinion angle as you say a "factor in traction" (such as a tuning tool) can be dangerous.

The pinion's U-joint angle isn't the only thing to check, the front slip yoke u-joint operating angle must be factored in as well to keep the drive shaft happy (as close to "in phase" as possible). Adjusting the angles too far from "equal but opposing" and the driveshaft could spin out of phase ("jump rope effect").

The only real way using pinion angle as a suspension adjustment tool works to effect how the car "hooks" is [A] the pinion actually pushs/rotates/interacts with/against a solid/rigid chassis component, such as a pinion snubber type traction device (not dangerous). And [B] adding a bunch of pinion angle (either direction) to a car killing some power reaching the rear tires because of frictional losses through increased U-joint binding (very dangerous).

For a street/highway use vehicle, keeping the front & back U-joints as close to "in phase" as possible (equal but opposing angles) under "real world" load is the best idea. But a "drag use only" combo (that will never see the street/highway) with a dedicated "race car" rear suspension might not always be set to a "true" equal but opposing angle setting. Since they are usually a stiffer suspension with less pinion rotation they can (at times) be set up with minimal angle settings (as close to 0.000* as possible under launch grunt loads ).

There is no "one-size-fits-all" pinion angle setting. You adjust it to the required/best setting for the cars intended use.......and LEAVE it there. It is not a "hook" adjusting/tuning tool.....unless you like testing driveshaft safety loops.

well put.

Anyone have a how-to to set pinion angle?

I've got a magnetic base angle indicator.

My motor sits about 20 degrees tilted to the rear and my rear axle is parallel with the ground in my F100.. I should fix this some time.. I can shim the crossmember some, but, don't know how to acheive the proper angle, other than eyeballing it.

Powerhouse Products sells a handy little doohicky that measures the angle but its easy enough to use your magnetic angle thing as well.

Just check the angle on the drive shaft and compare it to the angle on the motor.

ie if the motor is down at the back 20 degrees and the drive shaft is down at the back 16 degrees then you have a 4 degree difference.

Same thing for the actual pinion angle. There are tapered shims available to shim the rearend on a leaf spring set up but if your driveshaft to trans angle is bad your only option is to move the tail end of the trans or the front end of the motor.

dkp

how to set pinion angle:

1) Get an Anglemaster, this is a digital protractor it cost about 250 bucks.
2) put vehicle on flat ground
3) make sure both flanges on the trans and the pinion are parallel to the floor, this will make taking measurements easy.
4) take the Anglemaster rest it on the frame and hit the "zero" button
a) all drive line angles are determined by using the frame as reference.
5) measure the angle of the output shaft on the trans (use the output flange is the best)-measurement "A"
6) measure the angle of the driveshaft- measurement "B"
7) measure the pinion angle (once again use the flange on the pinion shaft)- measurement "C"
8) subtract the larger of the angles "A" and "B" this is output shaft angle
9) subtract the larger of the angles "B" and "C" this is pinion angle

the difference of both calculations should be within 1 degree of each other.

If they are not with 1 degree of each other uses shims to adjust the rear pinion under the springs, like has been mentioned.

If the front is not correct you will have to adjust the powertrain accordingly.

if you look at any factory manuals this is how it is done. Or talk to Dana/Spicer and this is their same procedure. Other wise you will get a wicked vibration and will over stress the u-joint and could break.

If you are going to use it just for the track you will have to actually play with the pinion angle till you get it within the 1 degree spec.

If I remember (without looking it up) the actual working angle of a u-joint is like 3-5 degrees this is best for both power take off and decel.

You can get an Anglemaster from a company called Production Tool Supply part number NA42-360. Or try and get one from a ford dealer ford part number 164-R2404. You can try and get it from the tool trucks but it will take about 3 weeks to get it and it will cost close to 600 bucks.

how to set pinion angle:

1) Get an Anglemaster, this is a digital protractor it cost about 250 bucks.
2) put vehicle on flat ground
3) make sure both flanges on the trans and the pinion are parallel to the floor, this will make taking measurements easy.
4) take the Anglemaster rest it on the frame and hit the "zero" button, all drive line angles are determined by using the frame as reference.
5) measure the angle of the output shaft on the trans (use the output flange is the best)-measurement "A"
6) measure the angle of the driveshaft- measurement "B"
7) measure the pinion angle (once again use the flange on the pinion shaft)- measurement "C"
8 ) subtract the larger of the angles "A" and "B" this is output shaft angle
9) subtract the larger of the angles "B" and "C" this is pinion angle

the difference of both calculations should be within 1 degree of each other.

If they are not with 1 degree of each other uses shims to adjust the rear pinion under the springs, like has been mentioned.

If the front is not correct you will have to adjust the powertrain accordingly.

if you look at any factory manuals this is how it is done. Or talk to Dana/Spicer and this is their same procedure. Other wise you will get a wicked vibration and will over stress the u-joint and could break.

If you are going to use it just for the track you will have to actually play with the pinion angle till you get it within the 1 degree spec.

If I remember (without looking it up) the actual working angle of a u-joint is like 3-5 degrees this is best for both power take off and decel.

You can get an Anglemaster from a company called Production Tool Supply part number NA42-360. Or try and get one from a ford dealer ford part number 164-R2404. You can try and get it from the tool trucks but it will take about 3 weeks to get it and it will cost close to 600 bucks.

I used the 10 dollar magnetic deal from Ace hardware, worked fine, and when I had Duffy recheck it when he scaled the car is was dead on.