Pinion Angle
12-22-2008, 01:20 PM
#1
Banned
Thread Starter
iTrader: (58)
Join Date: Mar 2004
Location: Leola, PA
Posts: 756
Likes: 0
Received 0 Likes
on
0 Posts
Pinion Angle I've been reading and searching all about pinion angle, but am confused on one thing, is it (pinion angle) - (driveshaft angle) or is it (driveshaft angle) - (pinion angle).
12-22-2008, 01:37 PM
#2
You actually add the two figures together. You might be adding two negative degrees or you could be adding a positive figure and a negative. Heres an example. -3 degrres drive shaft angle plus +2 pinion = -1 total. If you have any questions give me a call. Its easier to explain the process over the phone than it is to type it out.
12-22-2008, 01:38 PM
#3
Think of the transmission output yoke and the pinion yoke as being parallel to each other. This is ideal if there were no compression in the rear suspension that result in the change of the u-joint angles. Of course this is not the case.
You want the pinion yoke to be 2 degrees below parallel so that when you launch, the two parts become parallel to maximize torque transfer and reduce the chance of breakage.
Do a search on driveline angle. There are some very useful diagrams to be viewed.
You want the pinion yoke to be 2 degrees below parallel so that when you launch, the two parts become parallel to maximize torque transfer and reduce the chance of breakage.
Do a search on driveline angle. There are some very useful diagrams to be viewed.
12-22-2008, 05:40 PM
#4
Banned
Thread Starter
iTrader: (58)
Join Date: Mar 2004
Location: Leola, PA
Posts: 756
Likes: 0
Received 0 Likes
on
0 Posts
This is where i sit right now.....
Pinion angle is +1
Driveshaft Angle is +3
Now if i take 1-3 I get -2
I can plainly see that the driveshaft and the pinion are at a \/ shape pointing down, I still have a decel vibe when off the gas.....which i've heard is because of to much of a negative angle.
I did my reading with the car on jackstands on all 4 corners, but i'm thinking that it still might be a little off considering it's not on the ground.
If it matters at all i've also taken a reading from the front of the crank pulley and thats telling me +3.
All readings are from the pass. side of the car.
Any other thoughts or comments.
Pinion angle is +1
Driveshaft Angle is +3
Now if i take 1-3 I get -2
I can plainly see that the driveshaft and the pinion are at a \/ shape pointing down, I still have a decel vibe when off the gas.....which i've heard is because of to much of a negative angle.
I did my reading with the car on jackstands on all 4 corners, but i'm thinking that it still might be a little off considering it's not on the ground.
If it matters at all i've also taken a reading from the front of the crank pulley and thats telling me +3.
All readings are from the pass. side of the car.
Any other thoughts or comments.
12-24-2008, 03:48 PM
#7
TECH Fanatic
iTrader: (31)
Join Date: Jun 2004
Location: Mesa, AZ
Posts: 1,284
Likes: 0
Received 0 Likes
on
0 Posts
Looks as though you measured correctly (based on your crank pulley and pinion angles you are at -2 degrees). I'm running a 9 inch too and the only way I could get rid of all vibration was to run at zero to -1/2 degree. Try moving towards zero in half degree increments and see if that does it.
Trending Topics
12-24-2008, 06:05 PM
#8
Banned
Thread Starter
iTrader: (58)
Join Date: Mar 2004
Location: Leola, PA
Posts: 756
Likes: 0
Received 0 Likes
on
0 Posts
Looks as though you measured correctly (based on your crank pulley and pinion angles you are at -2 degrees). I'm running a 9 inch too and the only way I could get rid of all vibration was to run at zero to -1/2 degree. Try moving towards zero in half degree increments and see if that does it.
I'm starting to think it's my driveline angle up at the trans thats giving me my problems.........I'm running a poly mount with the spacer on the trans and i think that with the new crossmember it raised the tranny up a little and is throwing the driveline angle off, i now have the pinion angle set at -2 in relevance to the ground, still with no change to the vibration, I will be removing the spacer and doing the bump mod to the mount and i might have to even shim the crossmember down to get the equal/opposite that it needs, hopefully that will eliminate the harmonic vibration that I have, I'll post my results has i have them.
12-25-2008, 11:16 AM
#9
"I now have the pinion angle set at -2 degrees in relevance to the ground"
this is more than likely the entire problem...
pinion angle should never be measured in relevance to the horizon. pinion angle is always set measuring the difference between the angle of the driveshaft in relation to the angle of the pinion. in correct theory, the pinion should be at the same angle as the crankshaft centerline. the pinion is normally a bit lower in height compared to the to the crankshaft, therefore giving the pinion and driveshaft a "negative pinion angle". this simulates a "v" shape in the pinion to driveshaft relation. a "positive" angle would simulate a "^" shape and is not recommended.
"pinion angle" or what GM calls "driveline angle/u-joint working angle" is optimum at 1.5 degrees. this allows the u-joint to articulate and move the needles within the u-joint. a u-joint that doesn't articulate would wear out with the needle bearing rollers being loaded in the same spot all the time.
if your pinion measures 2* and your driveshaft measures 4* on the same side of zero on the angle finder, then there is 2* working angle.
if your pinion measures 2* and your driveshaft measures 4* on different sides of zero, then you have 6* working angle.
if your pinion measures 2* and your driveshaft measures 2* on the same side of zero, then you have 0* working angle.
you could have the nose of the car on the ground and get much different numbers, but it all works the same. it is simply the difference between the two.
the f-body car seems to like 1.5* to 2.0* negative pinion angle. the more angle you have, vibration chances will be greater. the entire driveline should be checked to make the car as best as it can be. this would include checking and adjusting the engine/trans angle to make the front u-joint the same as the rear. you are realistically looking for both angles to be the same as they would cancel eachother out and eliminate vibrations. being that the pinion on a 9 inch rearend is located lower from centerline than the stock rearend, if the pinion is set at the stock angle the entire "driveline angle" numbers will automatically increase. if you want stock angles, then the trans would need to be lowered a bit and the rerarend would need to have the pinion rolled higher than the stock angle.
in the performance mind, the 9 inch pinion being lower would instantly get somewhere around that 2* negative with the same rearend angle as stock. with different ride heights, transmissions different than stock, body tolerances, and worn mounts is the reason we make the torque arm adjustable to accomodate these differences and set the angles where they need to be.
this is more than likely the entire problem...
pinion angle should never be measured in relevance to the horizon. pinion angle is always set measuring the difference between the angle of the driveshaft in relation to the angle of the pinion. in correct theory, the pinion should be at the same angle as the crankshaft centerline. the pinion is normally a bit lower in height compared to the to the crankshaft, therefore giving the pinion and driveshaft a "negative pinion angle". this simulates a "v" shape in the pinion to driveshaft relation. a "positive" angle would simulate a "^" shape and is not recommended.
"pinion angle" or what GM calls "driveline angle/u-joint working angle" is optimum at 1.5 degrees. this allows the u-joint to articulate and move the needles within the u-joint. a u-joint that doesn't articulate would wear out with the needle bearing rollers being loaded in the same spot all the time.
if your pinion measures 2* and your driveshaft measures 4* on the same side of zero on the angle finder, then there is 2* working angle.
if your pinion measures 2* and your driveshaft measures 4* on different sides of zero, then you have 6* working angle.
if your pinion measures 2* and your driveshaft measures 2* on the same side of zero, then you have 0* working angle.
you could have the nose of the car on the ground and get much different numbers, but it all works the same. it is simply the difference between the two.
the f-body car seems to like 1.5* to 2.0* negative pinion angle. the more angle you have, vibration chances will be greater. the entire driveline should be checked to make the car as best as it can be. this would include checking and adjusting the engine/trans angle to make the front u-joint the same as the rear. you are realistically looking for both angles to be the same as they would cancel eachother out and eliminate vibrations. being that the pinion on a 9 inch rearend is located lower from centerline than the stock rearend, if the pinion is set at the stock angle the entire "driveline angle" numbers will automatically increase. if you want stock angles, then the trans would need to be lowered a bit and the rerarend would need to have the pinion rolled higher than the stock angle.
in the performance mind, the 9 inch pinion being lower would instantly get somewhere around that 2* negative with the same rearend angle as stock. with different ride heights, transmissions different than stock, body tolerances, and worn mounts is the reason we make the torque arm adjustable to accomodate these differences and set the angles where they need to be.
12-25-2008, 11:30 AM
#10
Banned
Thread Starter
iTrader: (58)
Join Date: Mar 2004
Location: Leola, PA
Posts: 756
Likes: 0
Received 0 Likes
on
0 Posts
"I now have the pinion angle set at -2 degrees in relevance to the ground"
this is more than likely the entire problem...
pinion angle should never be measured in relevance to the horizon. pinion angle is always set measuring the difference between the angle of the driveshaft in relation to the angle of the pinion. in correct theory, the pinion should be at the same angle as the crankshaft centerline. the pinion is normally a bit lower in height compared to the to the crankshaft, therefore giving the pinion and driveshaft a "negative pinion angle". this simulates a "v" shape in the pinion to driveshaft relation. a "positive" angle would simulate a "^" shape and is not recommended.
"pinion angle" or what GM calls "driveline angle/u-joint working angle" is optimum at 1.5 degrees. this allows the u-joint to articulate and move the needles within the u-joint. a u-joint that doesn't articulate would wear out with the needle bearing rollers being loaded in the same spot all the time.
if your pinion measures 2* and your driveshaft measures 4* on the same side of zero on the angle finder, then there is 2* working angle.
if your pinion measures 2* and your driveshaft measures 4* on different sides of zero, then you have 6* working angle.
if your pinion measures 2* and your driveshaft measures 2* on the same side of zero, then you have 0* working angle.
you could have the nose of the car on the ground and get much different numbers, but it all works the same. it is simply the difference between the two.
the f-body car seems to like 1.5* to 2.0* negative pinion angle. the more angle you have, vibration chances will be greater. the entire driveline should be checked to make the car as best as it can be. this would include checking and adjusting the engine/trans angle to make the front u-joint the same as the rear. you are realistically looking for both angles to be the same as they would cancel eachother out and eliminate vibrations. being that the pinion on a 9 inch rearend is located lower from centerline than the stock rearend, if the pinion is set at the stock angle the entire "driveline angle" numbers will automatically increase. if you want stock angles, then the trans would need to be lowered a bit and the rerarend would need to have the pinion rolled higher than the stock angle.
in the performance mind, the 9 inch pinion being lower would instantly get somewhere around that 2* negative with the same rearend angle as stock. with different ride heights, transmissions different than stock, body tolerances, and worn mounts is the reason we make the torque arm adjustable to accomodate these differences and set the angles where they need to be.
this is more than likely the entire problem...
pinion angle should never be measured in relevance to the horizon. pinion angle is always set measuring the difference between the angle of the driveshaft in relation to the angle of the pinion. in correct theory, the pinion should be at the same angle as the crankshaft centerline. the pinion is normally a bit lower in height compared to the to the crankshaft, therefore giving the pinion and driveshaft a "negative pinion angle". this simulates a "v" shape in the pinion to driveshaft relation. a "positive" angle would simulate a "^" shape and is not recommended.
"pinion angle" or what GM calls "driveline angle/u-joint working angle" is optimum at 1.5 degrees. this allows the u-joint to articulate and move the needles within the u-joint. a u-joint that doesn't articulate would wear out with the needle bearing rollers being loaded in the same spot all the time.
if your pinion measures 2* and your driveshaft measures 4* on the same side of zero on the angle finder, then there is 2* working angle.
if your pinion measures 2* and your driveshaft measures 4* on different sides of zero, then you have 6* working angle.
if your pinion measures 2* and your driveshaft measures 2* on the same side of zero, then you have 0* working angle.
you could have the nose of the car on the ground and get much different numbers, but it all works the same. it is simply the difference between the two.
the f-body car seems to like 1.5* to 2.0* negative pinion angle. the more angle you have, vibration chances will be greater. the entire driveline should be checked to make the car as best as it can be. this would include checking and adjusting the engine/trans angle to make the front u-joint the same as the rear. you are realistically looking for both angles to be the same as they would cancel eachother out and eliminate vibrations. being that the pinion on a 9 inch rearend is located lower from centerline than the stock rearend, if the pinion is set at the stock angle the entire "driveline angle" numbers will automatically increase. if you want stock angles, then the trans would need to be lowered a bit and the rerarend would need to have the pinion rolled higher than the stock angle.
in the performance mind, the 9 inch pinion being lower would instantly get somewhere around that 2* negative with the same rearend angle as stock. with different ride heights, transmissions different than stock, body tolerances, and worn mounts is the reason we make the torque arm adjustable to accomodate these differences and set the angles where they need to be.
Thank you for the post Eric....it really gets confusing sometimes hearing all these differant ways of doing this, I'll keep working at it until I get her riding good.
12-26-2008, 12:15 PM
#11
10 Second Club
iTrader: (15)
Join Date: Nov 2001
Location: St. Michael, MN.
Posts: 4,519
Likes: 0
Received 0 Likes
on
0 Posts
FWIW - I've used the same adjustable Spohn TA for 7 years and have tried every imaginable method to adjust and measure pinion angle. I called around to shops who actually drag race and eventually settled on the Thunder Racing (now the Madman) method. It flat out works every time I use it; no drivetrain vibration or noise when street driving and the car hooks well at the track. I would suggest a search or call Madman Racing for a few tips.
12-26-2008, 01:02 PM
#13
Staging Lane
Join Date: Mar 2006
Location: upstate NY
Posts: 65
Likes: 0
Received 0 Likes
on
0 Posts
+3- and loaded as the way you typically drive it- You want the angle to be close to right for cruising for minimum vibration- a degree or two negative if you are more concerned with launching, where the axle and pinion will torque wrap up, bringing the measurement where it should be under load-
12-28-2008, 09:56 AM
#14
Banned
Thread Starter
iTrader: (58)
Join Date: Mar 2004
Location: Leola, PA
Posts: 756
Likes: 0
Received 0 Likes
on
0 Posts
Some new findings.......
Took my midwest crossmember out and matched it up with my stock crossmember.......well big differance to say the least.....no matter how much i would have adjusted my pinion angle....it would have never been right, so long story short i did do the plate and shave mod to my poly mount, shimmed the crossmember down with 2 washers in between the crossmember and the body. Now that everything is set back correctly, i started adjusting and measuring the tailhousing and pinion and finally cam up with a 3 down on the tailhousing and a 2 up on the pinion which would give me a working angle of -1. I still have to do a little more adjusting here and there on the pinion to see if I can get it better, I still have a very very small amount of vibe around 40 and then again at 100+, which I might say it could be a little of my steel driveshaft as it sticks out of the tranny 1 3/4" from flange to tail, I will be getting it lengthened or might just buy a new one. So for anyone having issues with crossmember mounted TQ arms, make sure the stock crossmember matches up to the new one in height.
Took my midwest crossmember out and matched it up with my stock crossmember.......well big differance to say the least.....no matter how much i would have adjusted my pinion angle....it would have never been right, so long story short i did do the plate and shave mod to my poly mount, shimmed the crossmember down with 2 washers in between the crossmember and the body. Now that everything is set back correctly, i started adjusting and measuring the tailhousing and pinion and finally cam up with a 3 down on the tailhousing and a 2 up on the pinion which would give me a working angle of -1. I still have to do a little more adjusting here and there on the pinion to see if I can get it better, I still have a very very small amount of vibe around 40 and then again at 100+, which I might say it could be a little of my steel driveshaft as it sticks out of the tranny 1 3/4" from flange to tail, I will be getting it lengthened or might just buy a new one. So for anyone having issues with crossmember mounted TQ arms, make sure the stock crossmember matches up to the new one in height.
12-28-2008, 01:43 PM
#16
10 Second Club
iTrader: (15)
Join Date: Nov 2001
Location: St. Michael, MN.
Posts: 4,519
Likes: 0
Received 0 Likes
on
0 Posts
DiabloFormula - What torque arm are you using?
FYI - I still run the original trans mount because of the issue you mention. I also tried the 1LE mount (not the factory installed, but the service replacement from GM) and noticed it also changed the angle of the transmission, so I went back to the OEM mount.
FYI - I still run the original trans mount because of the issue you mention. I also tried the 1LE mount (not the factory installed, but the service replacement from GM) and noticed it also changed the angle of the transmission, so I went back to the OEM mount.
12-28-2008, 02:02 PM
#18
10 Second Club
iTrader: (15)
Join Date: Nov 2001
Location: St. Michael, MN.
Posts: 4,519
Likes: 0
Received 0 Likes
on
0 Posts
Thank I didn't see that. I ask because I helped my friend with installation and setup of the same rear end and TA with no problems. We did have to move the front of the TA to a different hole, but once we got it, it was just a matter of fine tuning the pinion angle. He also has a poly trans mount. I guess each car is different.
Here is a pic of the front cross member with the adjustment holes I'm referring to.
Here is a pic of the front cross member with the adjustment holes I'm referring to.