Nine Ball

iTrader: (38)

I'm about to install a new torque arm and lower control arms on my car, and some lower control arm adjustment brackets. (LG Motorsports items), What pinion angle should I set for my 12-bolt, and how do you do such a thing? How much of a difference will this make?

I'm wanting some 1.4X 60' times in a full weight car with a 6-speed. Help a brother out! <img src="gr_stretch.gif" border="0">

Tony <img src="images/icons/confused.gif" border="0">

BADZ

iTrader: (5)

Tony, the pinion angle is very important and you will need to get ya a pinion gauge. Steve set mine and set it at -2 degrees with me in the car and it work fine, it work so good that I broke my last tq arm on a serious launch @ 4400 rpms so I know it was working well at that angle. You need to have someone measure it while your in the car to get a good angle reading...

P.S. Steve's dad was there also to give us tips on the old school and the new..

[ December 14, 2001: Message edited by: BADZ ]</p>

Camaroholic

iTrader: (1)

You usin' the LG arm? I didn't think the pinion angle was adjustable on those. He sets 'em up that way for RR and AX. If it's a solid arm (no adjuster joint near the rear of the arm), then it's not adjustable, and you don't need to worry about it. <img src="gr_grin.gif" border="0">

-Andrew

Big Mike

iTrader: (4)

Tony,

I went through this whole ordeal back in May. After lots of research and asking around I was told that anything over -1.5 pinion angle was to much and the more negative you go, the more road noise you will get, and expect to change u-joints quite often. When you set the angle, the car must be on the ground (all 4 wheels), don't set the angle with the car up on a regular lift, if it's a drive on lift that's a different story. Remember as you go more and more negative you create a binding effect which in an extreme case will hurt performance.

mmiller

iTrader: (1)

Tony,

You might want to shoot Steve and Dennis an email regarding torque arm pinion angle. I think both of them have pinion angle gauges. Dennis has a Random Tech T/A and Steve has a BMR T/A.

Nine Ball

iTrader: (38)

Andrew, you are correct, the LG torque arm is solid. Their setup uses the adjustable lower control arms and variable mounting brackets to set the pinion angle. Just a different method.

Tony

ChrisB

Ideally under full load you want your pinion angle to be from 0 (pushing it) to -1. Basically you never want to see positive pinion angle as it will unload the rear end a bit.

Now depending on your suspension, track bite, etc. How much initial you need can vary greatly. I have run up to -4 degrees on the street without issue, though that mandates new u-joints every 6 months or so (and you don't need -4 on the street as street tires don't have enough *traction* to warrant it. On slicks may be another matter.


[quote]Andrew, you are correct, the LG torque arm is solid. Their setup uses the adjustable lower control arms and variable mounting brackets to set the pinion angle. Just a different method.
Tony
<hr></blockquote>

Don't like the sound of that. If you vary the length of your LCA to change your pinion angle you will (1) be putting it in an instant bind with the TA since this specific to a certain pinion angle. (2) Your LCA's will swing on a different arc than the T/A. Now you have some give in your torque arm (for-aft movement - or you should), but I would be worried about putting additional stress on the TA.


Chris Bennight

Skelton

Very high hp cars can use -4 but .15-.2 would be a good starting point to try. Under acceleration you want the pinion angle to be as close to 0 as possible without going positive just like Chris said. Its also true that the more negative you go, the more bind you have so you get more noise and quicker wear on u-joints and pinion bearings.

Smoke_ur_5.0

iTrader: (2)

Good thread! I am in the market for a torque arm here too. I am sold on the Billingsley racing setup. I have been taking with them recently and it is one baaaad dude for a torque arm.

Take a look at the pic real qic.



The T/A mounts to a new fabbed tranny crossmember in stead of the tranny itself..also it's longer than the other T/A that mount in the rear brace area...longer means more leverage. Also they said that the tranny crossmember will have a built in drive shaft loop that extends off of it.
If you look at thier fabbed crossmemeber it appears that it has different holes for different pinion angles..looks like a good quick way to switch to a more aggressive pinion angle at the track or to try out different angles to see how it affects your launch.

As soon as they get it into production I'm gonna try it out.

[ December 14, 2001: Message edited by: Smoke_ur_5.0 ]</p>

Skelton

Looks very sweet and noisy to boot. Should be the ticket for low 60 fters. <img src="graemlins/gr_hail.gif" border="0" alt="[hail]" />

ChrisB

The billingsley setup looks nice - I have emailed Jay about it also (pricing/availability).

[quote]The T/A mounts to a new fabbed tranny crossmember in stead of the tranny itself..also it's longer than the other T/A that mount in the rear brace area...longer means more leverage. <hr></blockquote>

As I understand it reducing instant center will increase the anti-squat characterstics of a chassis. So now the torque that would be wasted on spring deflection, etc. is instead trasmitted to the rear end housing and acts as an increase in the normal force (more traction). Now I know with high hp cars this can lead to some wild wheels up launches, but at the power level most of us are talking about (<650-700+ rwhp) I would think a shorter instant center would be preferrable? (posted this in the JFP/SS TA thread and didn't get a reply there either <img src="gr_stretch.gif" border="0"> ).

Chris

[ December 14, 2001: Message edited by: ChrisB ]</p>

steve

hmm...

nice to see some people chimming in on this.

for starts, i would go with a -2 pinion angle.
adjust from there.

be sure what ever you do to have your weight in the drivers seat when you do it also. it will change other wise.

i will have to say that dont like the thought of changin the angle using the lower control arm either. but ya never know, it might work out better.


steve frank

Pro Stock John

iTrader: (34)

-2 thru -2.5 o over here in Chicago on my car and HackerJoe's car.

I have the RT tech tq arm but plan to get Billingsley's front mount (at least).

02 'Hawk

I just bought the latest spohn street versioin, it has a pivoting front mount of some sort. im going to set initial pinion angle at -0.5 for starters, on a drive up lift.

Chris

Terry Burger

iTrader: (4)

Tony your 60' times are already pretty good for an M6, don't expect to pick up anything with the new suspension pieces. If you really want to change something 4.30s and some 28" slicks would be the way to go.

Pinion angle should be left as close to -2 as possible. If the car doesn't hook, going lower will help reduce the shock to the tires at launch, at the expense of a few hp going down the track.

Mike Hoffpauir

What is factory pinion angle?

Colonel

[quote]Originally posted by Mike Hoffpauir:
<strong>What is factory pinion angle?</strong><hr></blockquote>

I don't know exactly (maybe someone will chime in) but it's not much. Maybe a half degree or so?

02 'Hawk

+ or - ? guys are sayint to set mine at ~ -2 on the new Spohn arm....

Terry Burger

iTrader: (4)

There is about -2 built in to the stock housing, + another degree or two in the arm.

Patrick G

iTrader: (14)

You guys are going to be sorely disappointed looking for tenths in a torque arm...even more so with adjusting pinion angle. I tried different angles...-8 all the way to +2 degrees and found no difference in traction on the street or at the track (Random Torque Arm). The longer the torque arm, the less degrees nose down you need to achieve 0 degrees under launch. For most suspensions, it's going to be between -1 and -2 degrees nose down.

The real traction advantage comes from looking past the torque arm. It's all in the first foot in front of the rear axle. The Pete Z bars use axle torque (twisting torque) to push the body up and plant the tires down. There is actually separation between the body and the rear end, which plants the tires to the pavement with much greater force. Squat is bad...separation is good...at least in a 9 to 11 second ride. The torque arm is just along for the ride...it can't really have that dramatic of an influence on traction because of its great length. Too much leverage is lost over those 4 feet. Look further back for traction, it's not in the torque arm. If you don't believe me, crawl under any F-Body running stock eliminator and you will see where all the effort is spent...it's not in the torque arms...open your eyes!