Page 1 of 3 123 LastLast
Results 1 to 20 of 48

Drivetrain Angles - Pinion, TQ Arm, Trans, Help

This is a discussion on Drivetrain Angles - Pinion, TQ Arm, Trans, Help within the Drivetrain forums, part of the LSx Technical Help Section category; Alright guys, I am experiencing some bad wheel hop at the track. Not only is it killing my 60',1/4 mile ...

  1. #1
    Veteran Hi-Po's Avatar
    Join Date
    Nov 2005
    Location
    Florida
    Posts
    10,461

    Black
    1999 TA WS.6

    Drivetrain Angles - Pinion, TQ Arm, Trans, Help

    Alright guys, I am experiencing some bad wheel hop at the track. Not only is it killing my 60',1/4 mile time... Im going to break something soon. I bought an angle finder from UMI. When I hang the angle finder from the TQ Arm mounting post on my Moser 9".... it reading 0*. When I hang it on my Rear end driveshaft yoke... It read +3*. When I hang it on my trans out putshaft yoke it read +3*. Do I want the pinion angle (rear end yoke) at -2*? Any input or advice from guys who have measured it before would be awesome. Rear end has jack stands under the tubes, front tires sitting on big blocks of wood. Suspension is loaded.

    Rear end is a Moser 9", BMR adjustable Tq Arm, BMR adjustable trans cross memeber, Brand new PST aluminum Driveshaft.

    Trying to get back to the track tomorrow, but will not go again untill this wheel hop is takn care of.


    Also, I was told by UMI to put my LCA's in the LOWEST hole. Right now they are straight when suspension is loaded.

  2. #2
    Senior Member bills98ta's Avatar
    Join Date
    Feb 2007
    Location
    St Thomas, PA
    Posts
    5,047

    White
    1998 Trans Am

    With the car preloaded, you want the pinion & driveshaft down 1 1/2* - 3*
    I have mine about 2 1/2* and the LCA's at the bottom... That forces the rear & tires down to plant harder... I've had the tire shake before real bad... The LCA'a took care of it !

  3. #3
    Moderator Firebirdjones's Avatar
    Join Date
    May 2006
    Location
    Arizona
    Posts
    12,552
    When I set them up I measure a bit different. I don't trust that the torque arm mounts on the housing are exactly parallel with the pinion yoke. So what I do is measure from the yoke itself with the driveshaft removed, I stick a deep well socket in the yoke where the u-joint would sit, and measure from that. Rotate the yoke so the mounting points are vertical (up and down).
    I take my other measurement directly from the driveshaft itself while it's connected to the rear.

    The difference should be anywhere from -2 to -4 degrees for a street car.

    But from what you are describing, it sounds as though you need to lower your pinion angle quite a bit, which should increase the positive number you have on the shaft,,,and start to show a negative on the pinion gear,,,simply subtract the difference and adjust until you reach -2 or so and give that a shot. Then work from there with a little trial and error.

  4. #4
    Senior Member bills98ta's Avatar
    Join Date
    Feb 2007
    Location
    St Thomas, PA
    Posts
    5,047

    White
    1998 Trans Am

    A4 or M6 ? If A4, what stall ? What tires ?

  5. #5
    Veteran Hi-Po's Avatar
    Join Date
    Nov 2005
    Location
    Florida
    Posts
    10,461

    Black
    1999 TA WS.6

    Quote Originally Posted by bills98ta View Post
    With the car preloaded, you want the pinion & driveshaft down 1 1/2* - 3*
    I have mine about 2 1/2* and the LCA's at the bottom... That forces the rear & tires down to plant harder... I've had the tire shake before real bad... The LCA'a took care of it !
    Really? I was wondering how much of a difference lowering the LCA's would do. I have a mile of wiring ran throughout my car right now... so getting to the track will mean tieing all that up I might just try the LCA if Im in a rush to go down the 1/4 mile tomorrow.
    Quote Originally Posted by Firebirdjones View Post
    When I set them up I measure a bit different. I don't trust that the torque arm mounts on the housing are exactly parallel with the pinion yoke. So what I do is measure from the yoke itself with the driveshaft removed, I stick a deep well socket in the yoke where the u-joint would sit, and measure from that. Rotate the yoke so the mounting points are vertical (up and down).
    I take my other measurement directly from the driveshaft itself while it's connected to the rear.

    The difference should be anywhere from -2 to -4 degrees for a street car.

    But from what you are describing, it sounds as though you need to lower your pinion angle quite a bit, which should increase the positive number you have on the shaft,,,and start to show a negative on the pinion gear,,,simply subtract the difference and adjust until you reach -2 or so and give that a shot. Then work from there with a little trial and error.
    Well, my driveshaft is aluminum, so i cant hang the AF from it.

    So, Im going to LOWER my pinion/Tq Arm angle until I find -2*, right? Or am I lowering the pinion angle until I have such a negative number that I can subtract from the positive driveshast number to reach the -2/-4 final?

    In the end... I subtract the pinion angle from the driveshaft angle and want both of them to be between -2 / -4 correct? Am I missing something?

  6. #6
    Moderator Firebirdjones's Avatar
    Join Date
    May 2006
    Location
    Arizona
    Posts
    12,552
    You want to lower it enough to the point where you subtract the two and come up with a final -2 to -4. Your last sentence in that question was correct.

    For example if you show +5 on the driveshaft and -7 on the yoke (rearend) you have -2

    As you lower the pinion you'll find the negative number on the yoke will increase more than the positive number on the drive shaft. Eventually you will surpass that +3 reading you got on the driveshaft with a negative number on the yoke.

    The angle finder doesn't have to stick to the drive shaft,,,just hold it on there and take a look.
    Last edited by Firebirdjones; 09-01-2009 at 06:32 PM.

  7. #7
    Senior Member bills98ta's Avatar
    Join Date
    Feb 2007
    Location
    St Thomas, PA
    Posts
    5,047

    White
    1998 Trans Am

    With the car on the ground, the LCA's should be angled up towards the crank of the motor for the instant center. My moser made them angle down towards the bottom of the front tires, until I did the relo brackets.
    Still wondering about what tires & tranny setup...

  8. #8
    Veteran Hi-Po's Avatar
    Join Date
    Nov 2005
    Location
    Florida
    Posts
    10,461

    Black
    1999 TA WS.6

    Transmission is M6

    Tires are MT Et Streets radials as of now.

  9. #9
    Veteran Hi-Po's Avatar
    Join Date
    Nov 2005
    Location
    Florida
    Posts
    10,461

    Black
    1999 TA WS.6

    Quote Originally Posted by Firebirdjones View Post
    You want to lower it enough to the point where you subtract the two and come up with a final -2 to -4. Your last sentence in that question was correct.

    For example if you show +5 on the driveshaft and -7 on the yoke (rearend) you have -2

    As you lower the pinion you'll find the negative number on the yoke will increase more than the positive number on the drive shaft. Eventually you will surpass that +3 reading you got on the driveshaft with a negative number on the yoke.

    The angle finder doesn't have to stick to the drive shaft,,,just hold it on there and take a look.
    That makes since. Thank you, hopefully I can at least get the LCA's and the angle set at get to the track tomorrow.

  10. #10
    Senior Member bills98ta's Avatar
    Join Date
    Feb 2007
    Location
    St Thomas, PA
    Posts
    5,047

    White
    1998 Trans Am

    Quote Originally Posted by Hi-Po View Post
    Transmission is M6

    Tires are MT Et Streets radials as of now.
    Cool, That's what I'm running. ( 275/60-15 ) I'm finding that 19.5 - 21.5 lbs of air works for me. Cold, before my 1'rst round, I set them at 20.5, and they hook great !!!
    As far as the M6, I can't do it... I have to stick with the A4 / 4600 stall !!! LOL !!!

  11. #11
    Veteran Hi-Po's Avatar
    Join Date
    Nov 2005
    Location
    Florida
    Posts
    10,461

    Black
    1999 TA WS.6

    Quote Originally Posted by bills98ta View Post
    Cool, That's what I'm running. ( 275/60-15 ) I'm finding that 19.5 - 21.5 lbs of air works for me. Cold, before my 1'rst round, I set them at 20.5, and they hook great !!!
    As far as the M6, I can't do it... I have to stick with the A4 / 4600 stall !!! LOL !!!
    Thanks for the PSI stats. I have been fighting with PSI settings for weeks. I always wish I was an auto when I get to the track, but on the street I just love my manual.

    Ive been setting my tires at 19 PSI for the first run. Im pretty sure I have understand the angle setting.

  12. #12
    Senior Member bills98ta's Avatar
    Join Date
    Feb 2007
    Location
    St Thomas, PA
    Posts
    5,047

    White
    1998 Trans Am

    My wheel shake was so bad, both door mirrors would vibrate up to the sky, the console lid would fly open, the ash tray would fly out of the console, and eventully, I figured I was going to get punched in the face with an air bag...
    I've done some research on this matter ! LOL

  13. #13
    Veteran Hi-Po's Avatar
    Join Date
    Nov 2005
    Location
    Florida
    Posts
    10,461

    Black
    1999 TA WS.6

    Yea, its pretty violent with my car. I have some video of 2 weeks ago where it toss's my car sideways before it hooks. I cant wait to get resolved, by then though... racing season will be over.

  14. #14
    Member
    Join Date
    Nov 2008
    Location
    harrisburg pa.
    Age
    61
    Posts
    868

    black
    02 vette vert

    Quote Originally Posted by bills98ta View Post
    With the car on the ground, the LCA's should be angled up towards the crank of the motor for the instant center. My moser made them angle down towards the bottom of the front tires, until I did the relo brackets.
    Still wondering about what tires & tranny setup...
    what i think is odd is the factory LCA brackets are pointing the arms the wrong way to start with. everybody says if you lower the car you need the relocation brackets. looks to me you need them anyway! by the way, are you ST. Thomas as in Linglestown, or some other place with the same name?

  15. #15
    Senior Member bills98ta's Avatar
    Join Date
    Feb 2007
    Location
    St Thomas, PA
    Posts
    5,047

    White
    1998 Trans Am

    Quote Originally Posted by dklowrider View Post
    what i think is odd is the factory LCA brackets are pointing the arms the wrong way to start with. everybody says if you lower the car you need the relocation brackets. looks to me you need them anyway! by the way, are you ST. Thomas as in Linglestown, or some other place with the same name?
    I'm outside of Chambersburg on Rt 30 / Exit 16 on 81... Yea, the moser sets the angle worse than the stock rear... Haven't had wheel shake since I add the relo's !!!

  16. #16
    Veteran Hi-Po's Avatar
    Join Date
    Nov 2005
    Location
    Florida
    Posts
    10,461

    Black
    1999 TA WS.6

    Well, I got the LCA's in the bottom hole. I started to measure my angles and adjust... but it seems no matter what I did... that angles barely changed. I spent the rest of my day wiring. I enjoy wiring much more then laying under my car Will get at it tomorrow.

  17. #17
    Moderator Firebirdjones's Avatar
    Join Date
    May 2006
    Location
    Arizona
    Posts
    12,552
    Did you get anywhere with it?? It will probably take quite a bit of adjustment to get it correct.

    When I installed upper control arm no hop bars on my chevelle (GM 4 link) it basically relocated the upper control arms to change instant center. The same thing can be done with lower control arms as well.
    But it changed my pinion angle horribly. Adjustable upper arms were needed, and I had to shorten them nearly 2 inches to get pinion angle correct again. So it's not unusual, especially when you start getting into aftermarket control arms and relocation brackets etc....

  18. #18
    Veteran Hi-Po's Avatar
    Join Date
    Nov 2005
    Location
    Florida
    Posts
    10,461

    Black
    1999 TA WS.6

    I JUST got back on that. Just finished all my wiring

    Now, with my LCA's in the lowest hole, and the adjustment I just made... When I hang the AF on the bottom of the pumpkin it reads -4*

    When I hang the AF on the driveshaft (right in front of the yoke) it reads +4. So, that means im at 0* correct? Keep on adjusting...

  19. #19
    Moderator Firebirdjones's Avatar
    Join Date
    May 2006
    Location
    Arizona
    Posts
    12,552
    Yep that's "0",,,,,keep on going. Just a couple of degrees negative is what I would start with.

  20. #20
    Veteran Hi-Po's Avatar
    Join Date
    Nov 2005
    Location
    Florida
    Posts
    10,461

    Black
    1999 TA WS.6

    Alright, The driveshaft is +4*

    Reading under the pumkin is -6*

    Im going to tightened this up and try it.

Page 1 of 3 123 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. See the new COPO Camaro's awesomeness from many angles
    By Ed Blown Vert in forum General Help
    Replies: 2
    Last Post: 02-06-2016, 11:35 PM
  2. Rack and Pinion Howto `99 Trans Am
    By 79Firebird_99TA in forum Suspension and Handling
    Replies: 6
    Last Post: 10-21-2012, 09:43 PM
  3. Incest-Baby Lemonade.... Sharron Angles' special juice
    By ibanez7 in forum Political / Debate Forum
    Replies: 6
    Last Post: 10-05-2010, 01:12 PM
  4. Can't Fix Toe Angles?
    By hoss 2000 z-28 in forum Suspension and Handling
    Replies: 4
    Last Post: 03-30-2008, 08:46 AM
  5. My Burnout video from diffent angles. (03 cobra)
    By Musclefan21 in forum Almost Anything Goes
    Replies: 37
    Last Post: 01-29-2008, 04:53 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •