mindreaper

iTrader: (1)

I'm thinking of getting the UMI adjustable torque arm (tranny mounted) for my '99 Z28, which is lowered with Strano springs (it's not a radical drop, maybe about 1.3" or 1.5").

From what I've read, I need an adjustable torque arm if my car is lowered, is that correct?

Also: what is the right pinion angle for a car lowered like mine?

INMY01TA

iTrader: (1)

I'd assume -2 like any other car but not sure.

UMI Performance

iTrader: (77)

The pinion angle will vary slightly depending on the vehicle and whether it is a auto or manual and also what rear end is installed. But a -2 degree setting is usually the best compromise. Right now with the springs your driveline angle is positive and is most likely causing some poor traction.

If I can help anymore please ask. thank you!

Ryan

mindreaper

iTrader: (1)

Thanks for the reply. I thought -2 degree was for a stock height car, so surely I should set if differently now that I have Strano springs, no?

leadfoot4

iTrader: (1)

No, you really want the pinion angle to be (-)2 degrees, whatever the ride height of the car. Lowering the car changes this angle, and the adjustable torque arm allows you to return it to (-)2.

BMR Suspension

iTrader: (6)

Ideally, you want the pinion angle to be at 0 degrees WHILE DRIVING DOWN THE ROAD. The best way to achieve this in a torque arm car with poly bushings is to set the pinion angle at -2 degrees while the car is static. This is true for a lowered car also.

When you are ready to set the pinion angle, feel free to view the BMR 3-minute video on setting the pinion angle on an F-Body car. This video will help you whether you use a BMR torque arm or one by another manufacturer. The video is located on the front page of our website :

www.bmrfabrication.com

Good Luck!!

Sam Strano

iTrader: (41)

Every car is different to start with. Stock they are around 0, but that's not set in stone. The fact that every car is different means there is no absolute. Hell, you can't even get most folks to agree on how to measure pinion angle. And what's more is I can't think of a time I've been in a car that was lowered and had the pinion angle messed up to the point it actually caused a u-joint bind just from the lowering.

Cars most likely to have issues from lowering are the slammed ones. Sportlines, Intrax type springs. Or those that have adjustable TA's and folks have no idea on how to set them. In fact, unless there is a reason to change the TA, like the car wheelhops, or brake-hops, or the stock one is fractured--which comes from one or both of the things I mentioned--I generally don't do one and leave the GM one there.

You're asking what the "correct" pinion angle is for my springs. The question has nothing to do with the srpings, it has to do due with the angle (regardless of springs), and I don't know you'll get a consensus. The better located the axle is in regards to resisting rotation, the less negative angle you need. Leaf spring cars need a lot more negative pinion angle because the leaf springs wind up a lot more than a properly designed TA or control arm car.

BMR Suspension

iTrader: (6)

I agree with Sam. Many F-Body enthusiasts do not know how to set the pinion angle with an adjustable torque arm. That's why BMR recorded the video and released it to the LSx community free of charge. The video is helpful even if another manufacturers torque arm is purchased.

The intention was for this to be our contribution to the entire F-Body community, not just for BMR customers.

leadfoot4

iTrader: (1)

Thanks, guys, as it's a very good video. HOWEVER, if I remember correctly, as I just referred back to that video a couple of days ago, the narrator says that the stock torque arm provides (-)2 degrees of pinion angle....doesn't he??

mindreaper

iTrader: (1)

Thanks for the explanation, I understand much better now

And that video is neat!

JonCR96Z

iTrader: (33)

You don't listen very well, huh?

Quote:

"The non-adjustable (BMR torque arm) is factory preset with a -2 degree pinion angle at factory ride height." - Quote from the BMR video

INMY01TA

iTrader: (1)

I think you don't listen very well. Lol. He's asking about the stock torque arm, not the UMI non adj. He obviously has an UMI adj one and wants the same pa as the stocker. Which I myself am unsure of.

JonCR96Z

iTrader: (33)

No, he doesn't.

I edited my original post so you can understand it better.

And if you want to know what the stock one is just read some of the other posts in this thread. The stock one is designed with 0 degrees of pinion angle in mind. Now due to tolerances in the manufacturing process that may not always be entirely accurate. And with the stock stamped steel torque arm under load it's likely to be way positive because it allows so much more flexing than the aftermarket pieces.

Jon

INMY01TA

iTrader: (1)

You need meds or somethin man. Idiot? I noticed you edited your post. Kettle, you're black.

JonCR96Z

iTrader: (33)

I wrote that, then I thought well maybe he just didn't understand that I was quoting that video guy in my post. And it still appears that you don't get it.

INMY01TA

iTrader: (1)

I do get it. No I didn't understand in your 1st post you were Quoting the vid. You were however being kind of a dueschbag tho to him tho.

Lighten up.

leadfoot4

iTrader: (1)

PARDON ME, hotshot. Let me apologize for my mis-cue. The narrator of the video has the BMR adjustable bar in his hand when he says "The non-adjustable bar is set a (-)2 degrees at the factory". HOWEVER, what's in the picture??? The "factory", non adjustable, GM panhard bar.


I'm SORRY....for my 56 year old mind, the "word" factory being said, and the "image" of the factory bar on the video screen was a little confusing.....

BMR Tech2

iTrader: (5)

That video is a little confusing but our non adjustable torque arm does have -2 degrees built into it.

ZMONSTER!

iTrader: (9)

In theory, If your car is as the OP said lowered on strano springs, but you dont have any binding couldnt you just measure the pinion angle with the stock piece and then tune the adjustable TA to mimic that?
Not my idea so I cant really take credit for it, but that should work fine.

leadfoot4

iTrader: (1)

"In theory", yes. However, I think that's it's likely the pinion angle will change as the car is lowered. Therefore, you would want to correct for that.