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 ...
09-01-2009, 02:53 PM #1
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.
09-01-2009, 03:46 PM #2
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 !
09-01-2009, 04:55 PM #3
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.
09-01-2009, 05:07 PM #4
A4 or M6 ? If A4, what stall ? What tires ?
09-01-2009, 05:18 PM #5
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?
09-01-2009, 05:28 PM #6
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 05:32 PM.
09-01-2009, 05:55 PM #7
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...
09-01-2009, 06:24 PM #8
Transmission is M6
Tires are MT Et Streets radials as of now.
09-01-2009, 06:28 PM #9
09-01-2009, 06:36 PM #10
09-01-2009, 06:40 PM #11
Ive been setting my tires at 19 PSI for the first run. Im pretty sure I have understand the angle setting.
09-01-2009, 07:03 PM #12
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
09-01-2009, 07:29 PM #13
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.
09-02-2009, 03:29 PM #14
- Join Date
- Nov 2008
- harrisburg pa.
- 02 vette vert
09-02-2009, 03:58 PM #15
09-02-2009, 07:45 PM #16
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.
09-04-2009, 09:20 AM #17
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....
09-04-2009, 12:33 PM #18
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...
09-04-2009, 12:42 PM #19
Yep that's "0",,,,,keep on going. Just a couple of degrees negative is what I would start with.
09-04-2009, 12:51 PM #20
Alright, The driveshaft is +4*
Reading under the pumkin is -6*
Im going to tightened this up and try it.
Users Browsing this Thread
There are currently 1 users browsing this thread. (0 members and 1 guests)
By Ed Blown Vert in forum Firebird / WS6Replies: 22Last Post: 12-02-2009, 03:17 PM
By Ramairgod in forum Firebird / WS6Replies: 10Last Post: 10-13-2009, 08:47 AM
By meissen in forum Great Lakes MembersReplies: 126Last Post: 06-16-2009, 08:49 AM
By silver98TA in forum Parts For Sale / TradeReplies: 2Last Post: 05-07-2007, 12:47 PM