pinion angle ?

[TKGN1]

Long story short....
Recently lowered car with Eibach springs, after lowering, my 60' times sucked, best was a 1.9.
I decided to check pinion angle, was way off, -10 degrees. To fix this problem I got some adjustable uppers, installed and set rear to -2 degrees (set degrees by using the drive shaft angle minus angle of u-joint).
After finishing I noticed the axle had moved way back in the wheel well, almost to the point where the tire was rubbing the frame at the rear. Decided to make a set of lowers.
I made my lowers out of aluminum (I'm a machinist) and shortened the distance between the two mounting locations (by 5/8") to bring the rear back into the center of the wheel well. Question is, I havn't yet installed them and does this sound like a reasonable way to correct the problem?
Is -2 degrees a good setting for street/strip use?

Thanks for any input.
Todd

 

[Sleeper1987]

Long story short....
Recently lowered car with Eibach springs, after lowering, my 60' times sucked, best was a 1.9.
I decided to check pinion angle, was way off, -10 degrees. To fix this problem I got some adjustable uppers, installed and set rear to -2 degrees (set degrees by using the drive shaft angle minus angle of u-joint).
After finishing I noticed the axle had moved way back in the wheel well, almost to the point where the tire was rubbing the frame at the rear. Decided to make a set of lowers.
I made my lowers out of aluminum (I'm a machinist) and shortened the distance between the two mounting locations (by 5/8") to bring the rear back into the center of the wheel well. Question is, I havn't yet installed them and does this sound like a reasonable way to correct the problem?
Is -2 degrees a good setting for street/strip use?

Thanks for any input.
Todd

Ive always set my pinion angles to 4-6* negative.

 

[John Larkin]

Just make sure the driveshaft isn't going to bottom in the trans. 5/8 should not affect it though.

 

[TKGN1]

Installed the lowers last night and re-set the pinion angle. The 5/8" offset (mounting holes closer together) made about an inch difference once the uppers where re-adjusted, putting the wheel back in the "stock" position in the wheel well.
For those lowering their car, you might take this into consideration when setting pinion angle.
Not sure if any company makes "off-set" lowers for this type of situation, but it fixed my problem.

 

[KEVINS]

Long story short....
Recently lowered car with Eibach springs, after lowering, my 60' times sucked, best was a 1.9.
I decided to check pinion angle, was way off, -10 degrees. To fix this problem I got some adjustable uppers, installed and set rear to -2 degrees (set degrees by using the drive shaft angle minus angle of u-joint).
After finishing I noticed the axle had moved way back in the wheel well, almost to the point where the tire was rubbing the frame at the rear. Decided to make a set of lowers.
I made my lowers out of aluminum (I'm a machinist) and shortened the distance between the two mounting locations (by 5/8") to bring the rear back into the center of the wheel well. Question is, I havn't yet installed them and does this sound like a reasonable way to correct the problem?
Is -2 degrees a good setting for street/strip use?

Thanks for any input.
Todd

Yep. Have at it...

ks

 

[John Wilde]

I use -2 on the all the Regals and Mustangs that I help with.

 

[vader87]

John,
I would like to learn about this. What do I need to do and check. I have non adj lowers and adj uppers. Thanks!

 

[turbodave231]

Lots of myths out there on pinion angle.

You really need to measure the working angles of both front and rear u-joints. Optimally, they should be within 1 degree of each other to cancel out the speed variation that is created by a ujoint.

I measure +1 degree on the front and -3 on the rear at ride height. Under load the pinion will rise slightly.....maybe 1 degree. That leaves me with 1 degree difference front to rear.

A digital protractor is the best method to measure.

Here is a good article to read: Article

 

[John Wilde]

Dave's information is good, read through it when you get a chance.
I can tell you that in low 8 second GN going from -2 to -4* made the car really hard to hook. The same thing on a Fox bodied mustang caused the car to almost crash. This was an 9.3 Car.

 

[Way2QWK]

What would be the correct way to adjust the pinion angle if I dont have adjustable upper arms?

 

[TKGN1]

What would be the correct way to adjust the pinion angle if I dont have adjustable upper arms?

I don't believe you can adjust pinion angle without adjustable uppers on our cars.

 

[V6UnderPressure]

I have not yet measured my pinion angle, but I too have installed eibach springs. I kinda "eyeballed" it and figured that because it was lowered and it increased the angle of the u-joint to the transmission, I assumed I would need to EXTEND the adjustable uppers instead of SHORTENING them. In short, in a lowered car, (disregarding actually degrees of the pinion angle) should the adjustable uppers be lengthened or shortened?