Pinion angle setting....
Thread Starter
Joined: Sep 2003
Posts: 1,199
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From: Richmond, VA
Pinion angle setting.... Ok before you say "not another what's the pinion angle suppose be", I already know that a good street setting is -2*, but my question is where should measurements be taken? I've heard take the measurement off the driveshaft, other's say take it off the trans tailshaft/crankshaft pulley? I installed a Spohn adjustable a couple months ago and I used, what I thought was a good measurement method that I made up on my own, but now I know that it's wrong. So after reading some threads about it, here's what I came up with. Take a meaure off the trans tailshaft seal portion, say it was -5, and I measured the pinion seal portion of the rear end and the reading was +5*, what would be a 0 pinion angle correct? So by setting the rear end pinion angle on the rear to +3*, that should give me driveline angle of -2*, which is what I want, right?
the pinion should be -2* with respect to the driveshaft. The driveshaft measurement is more like a baseline. If that angle is 0* you want the pinion to be at -2*, if that angle is -5* you want the pinion to be at -7*.
the measurements you gave us give you a pinion angle of 10* if i am not mistaken. If both angles were at -5*, that would give you a pinion angle of 0*
measurement at rear end - measurement at driveshaft
the measurements you gave us give you a pinion angle of 10* if i am not mistaken. If both angles were at -5*, that would give you a pinion angle of 0*
measurement at rear end - measurement at driveshaft
Thread Starter
Joined: Sep 2003
Posts: 1,199
Likes: 0
From: Richmond, VA
well I read and read and read and I used what I thought was a good method. I took a measurement off the crank pulley, say is was 5*, then I took a measurement off the rear end pinion seal area and it was -5*. So from reading, what would be a 0* driveline angle, so then I set the pinion -7* to give me the -2* driveline angle I want. Does this sound right?
take a measurement on the driveshaft and then one on the flat part of the torque arm. Those are what i measure when setting mine.
(-5)-5=-10, so now your pinion angle is -10*
are you taking the measurement from the top of the crank pulley or the bottom, because if you measure it from the top and record +5*, it might actually be -5*.
Are all measurements taken at ride height or with the car up on ramps or jack stands?
(-5)-5=-10, so now your pinion angle is -10*
are you taking the measurement from the top of the crank pulley or the bottom, because if you measure it from the top and record +5*, it might actually be -5*.
Are all measurements taken at ride height or with the car up on ramps or jack stands?
Thread Starter
Joined: Sep 2003
Posts: 1,199
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From: Richmond, VA
Originally Posted by vjo90rs8
take a measurement on the driveshaft and then one on the flat part of the torque arm. Those are what i measure when setting mine.
(-5)-5=-10, so now your pinion angle is -10*
are you taking the measurement from the top of the crank pulley or the bottom, because if you measure it from the top and record +5*, it might actually be -5*.
Are all measurements taken at ride height or with the car up on ramps or jack stands?
(-5)-5=-10, so now your pinion angle is -10*
are you taking the measurement from the top of the crank pulley or the bottom, because if you measure it from the top and record +5*, it might actually be -5*.
Are all measurements taken at ride height or with the car up on ramps or jack stands?
yes the measurement was taken with jackstands under the rear, but the suspension was loaded. The measurement on the crank was taken at the face of the crank pulley.
TECH Fanatic
Joined: Nov 2004
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From: TX
OK... its real easy
Adjust the torque arm so that the needle points to the exact same spot on BOTH the driveshaft and the mounting plate on the differential.
This means you have a perfect 0* pinion angle. If you REALLY want to have a -2* pinion angle (which I do not advise for street driven cars) you simply adjust it so that the pinion starts to move down towards the ground. you can see which way the pinion goes when you turn the adjuster a certain way so it shouldnt be difficult to know that you're going down (negative). Just do it a little at a time and check with the finder. As you go you'll see that the gap gradually widens from being 37 and 37 (or whatever) to 38 and 36 and once the spread is 2 and youre sure that you adjusted it down and not up... you'll have a -2 pinion angle
However, your best bet is to go with 0 for a street driven car for 2 reasons.
1. You'll be certain that your pinion angle isn't way off. because if the DS and the pinion read the same number, you'll know that its 0
2. Its better for your pinion. less noise, less wear and most street driven cars aren't powerful enough to flex an aftermarket torque arm enough to need anything other than 0 degree pinion angle. The only reason for a negative pinion angle is so that when the car launches and things flex, the pinion angle comes up to 0 at launch and is less likely to break. But most street cars with an aftermarket TA are only going to be fudging the pinion angle maybe 1 degree at launch. +1 degree at launch with less than 500 HP and slicks is going to be totally fine. and its better than driving around all the time with a noisy and quickly wearing pinion
Adjust the torque arm so that the needle points to the exact same spot on BOTH the driveshaft and the mounting plate on the differential.
This means you have a perfect 0* pinion angle. If you REALLY want to have a -2* pinion angle (which I do not advise for street driven cars) you simply adjust it so that the pinion starts to move down towards the ground. you can see which way the pinion goes when you turn the adjuster a certain way so it shouldnt be difficult to know that you're going down (negative). Just do it a little at a time and check with the finder. As you go you'll see that the gap gradually widens from being 37 and 37 (or whatever) to 38 and 36 and once the spread is 2 and youre sure that you adjusted it down and not up... you'll have a -2 pinion angle
However, your best bet is to go with 0 for a street driven car for 2 reasons.
1. You'll be certain that your pinion angle isn't way off. because if the DS and the pinion read the same number, you'll know that its 0
2. Its better for your pinion. less noise, less wear and most street driven cars aren't powerful enough to flex an aftermarket torque arm enough to need anything other than 0 degree pinion angle. The only reason for a negative pinion angle is so that when the car launches and things flex, the pinion angle comes up to 0 at launch and is less likely to break. But most street cars with an aftermarket TA are only going to be fudging the pinion angle maybe 1 degree at launch. +1 degree at launch with less than 500 HP and slicks is going to be totally fine. and its better than driving around all the time with a noisy and quickly wearing pinion
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the pinion should be -2* with respect to the driveshaft. The driveshaft measurement is more like a baseline. If that angle is 0* you want the pinion to be at -2*, if that angle is -5* you want the pinion to be at -7*.
the measurements you gave us give you a pinion angle of 10* if i am not mistaken. If both angles were at -5*, that would give you a pinion angle of 0*
measurement at rear end - measurement at driveshaft
the measurements you gave us give you a pinion angle of 10* if i am not mistaken. If both angles were at -5*, that would give you a pinion angle of 0*
measurement at rear end - measurement at driveshaft
"-2" = meaning the pinion points lower in regard to the drive shaft. Best realized when using your 2 index fingers pointing at each other (tip to tip) and touching. The right finger representing the pinion and the left, the drive shaft. Roll the right and left fingers down so you have a "V" .. that is a negative angle (in regard to pinion agles). -2 isn't much .. it's damn near a straight line but the pinion does (and should) point lower that the drive shaft.
For the record .. using the crank pulley to measure "pinion angle" is useless, unless you factor in the tailshaft angle (which is WAY to complicated!!). The drive shaft has 2 angles .. one at the pinion and one at the tailshaft of the transmission. Each is different. The roll of the rear axle will determine pinion angle.
I hope that helps ...
For the record .. using the crank pulley to measure "pinion angle" is useless, unless you factor in the tailshaft angle (which is WAY to complicated!!). The drive shaft has 2 angles .. one at the pinion and one at the tailshaft of the transmission. Each is different. The roll of the rear axle will determine pinion angle.
I hope that helps ...
The pinion angle thing can be debated 10,000 different ways. We have a video on the front of our website that describes what we feel is the best way to set driveline angle.
www.bmrfabrication.com
www.bmrfabrication.com
That BMR vid is pretty good. I got sick of trying to measure mine with all of the different methods when I put my dana 60 in so I just started feeding it more pinion angle and driving it until it felt the way i wanted it too. I kept a couple of 2x4's in the trunk so i could just drive up on them one the street and adjust the angle on the spot.
