Homemade Torque Arm-Pics
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From: Downers Grove,IL
Homemade Torque Arm-Pics There are many nice T-arms available but I thought I would try building one myself. I figured I could do a decent job, save a few bucks, learn a thing or 2 and practice at my beginner level fab skills
.
After looking at all the available arms for some building ideas, I went with a short arm, shackle design. The Arm is built from mild steel tube, 1.3" OD, .133 ID, nothing special. The rear plates are 3/8" and 1/4". The total length of the arm including the Moser mount is 35" from the axle centerline. Should be good for a nice hard fast hit. I had built the arm with a rear adjuster at first. But as I messed with it, I found it really was not needed so I re-did the arm to eliminate the adjuster. Since the arm is pretty short, lowering the front pivot to adjust pinion angle does not make much of a change to the geometry like it would with a long arm. So I made a few shackles with preset pinion angles. It's pretty fast and easy to change them out. The shackle in the pic gives me -1' of angle.
I decided against a spherical bearing up front on the arm for a few reasons. The front bushing on the arm is solid with poly isolators.The lower bushing is poly.The entire arm is welded as 1 piece, although I kept the rear bolts in anyhow. I triangulated it with some plate but that was probably overkill.
The tube part of the cross member is actually a modified front sway bar that is 1" by .190 ID. While preparing to build the cross member I spotted my old sway bar and thought the bends and width sure looked like what I needed to tie into the roll bar and clear the exhaust and run tight to the floor pan for clearance. I added some plate to the ends and added 1/4" bar stock to stiffen everything up from any unwanted flex. The lower bushing mount is 1/4" thick and externally and internally welded to the tubing.The cross member is tied directly into my roll bar main hoop through the floor. It's a very strong unit and it would take a lot to flex it. Arm and cross member weigh 26lbs.
Steve
.After looking at all the available arms for some building ideas, I went with a short arm, shackle design. The Arm is built from mild steel tube, 1.3" OD, .133 ID, nothing special. The rear plates are 3/8" and 1/4". The total length of the arm including the Moser mount is 35" from the axle centerline. Should be good for a nice hard fast hit. I had built the arm with a rear adjuster at first. But as I messed with it, I found it really was not needed so I re-did the arm to eliminate the adjuster. Since the arm is pretty short, lowering the front pivot to adjust pinion angle does not make much of a change to the geometry like it would with a long arm. So I made a few shackles with preset pinion angles. It's pretty fast and easy to change them out. The shackle in the pic gives me -1' of angle.
I decided against a spherical bearing up front on the arm for a few reasons. The front bushing on the arm is solid with poly isolators.The lower bushing is poly.The entire arm is welded as 1 piece, although I kept the rear bolts in anyhow. I triangulated it with some plate but that was probably overkill.
The tube part of the cross member is actually a modified front sway bar that is 1" by .190 ID. While preparing to build the cross member I spotted my old sway bar and thought the bends and width sure looked like what I needed to tie into the roll bar and clear the exhaust and run tight to the floor pan for clearance. I added some plate to the ends and added 1/4" bar stock to stiffen everything up from any unwanted flex. The lower bushing mount is 1/4" thick and externally and internally welded to the tubing.The cross member is tied directly into my roll bar main hoop through the floor. It's a very strong unit and it would take a lot to flex it. Arm and cross member weigh 26lbs.
Steve
When I looked at the underbody shots, I was thinking, 'what is that bohemeth tube running down the length car'. At first glance it looked like a fabbed driveshaft 
I finally realized what it was (the y-pipe)...
The tq arm looks nice. I just put one together as well. That was a good idea using the swaybar-for sure an original. It didn't even cross my mind...
I finally realized what it was (the y-pipe)...The tq arm looks nice. I just put one together as well. That was a good idea using the swaybar-for sure an original. It didn't even cross my mind...
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Everything looks pretty beefy except for those two plates that join the arm to the cross member. Maybe use thicker gauge plate, or even better, box those in and make them a single unit.
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From: Downers Grove,IL
Thanks Guys. It was sort of fun building it.
Kevin, I installed my flooring myself so I feel I'm entitled to put anything I want on it
.
yeah it's a big Y Pipe I made running into a 4" mufflex system .
I'll try and take some more pics of it. I could have welded it as I have plates under the car already welded for the rollbar. I decided to just bolt it through the plates into the rollbar plates so It could be removed if necessary.It's bolted with 4 bolts each tightened to 110 ft/lbs of torque.
Well I agree, if there is a weak link it's the shackles. They are 3/16" thick and since the load on them is pretty much just a up/down motion and distributed through 4 holes I did not see a need to box it. Plus it let's them flex a bit for lateral motion. I checked out how the arm responds to one wheel being jacked up to simulate lateral motion. If the car was a road racer I would for sure use a sperical bearing up front to allow the arm bind free lateral motion and use beefier shackles. I can fit a huge single bearing to replace the poly bushing on the cross member with a load rating equal to two 3/4" rod end bearings.But I think for my intentions for the car it's not needed.
Looking at BMR's and Wolfes arms, the shackles they use don't appear any beefier.
I'll keep an eye on them and If I see any reason to upgrade them I will.
Next project is a rear drag sway bar.
Steve
Kevin, I installed my flooring myself so I feel I'm entitled to put anything I want on it
.
When I looked at the underbody shots, I was thinking, 'what is that bohemeth tube running down the length car'. At first glance it looked like a fabbed driveshaft I finally realized what it was (the y-pipe)...
I finally realized what it was (the y-pipe)...
.
Is it possible to get some pics that better illustrate where the crossmember attaches?
Everything looks pretty beefy except for those two plates that join the arm to the cross member. Maybe use thicker gauge plate, or even better, box those in and make them a single unit.
Looking at BMR's and Wolfes arms, the shackles they use don't appear any beefier.
I'll keep an eye on them and If I see any reason to upgrade them I will.
Next project is a rear drag sway bar.
Steve
Joined: Nov 2001
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From: Cecil County Raceway!!!
the Instant center of that T/A is pretty far back...Its going to want to hit very hard I think...hopefully it don't put you on the rear bumper 
Looks sweet though...we are going to build a custom T/A for mine this spring
Looks sweet though...we are going to build a custom T/A for mine this spring
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From: Downers Grove,IL
the Instant center of that T/A is pretty far back...Its going to want to hit very hard I think...hopefully it don't put you on the rear bumper
I had looked into building a set of short ladder bars like the Pete Z setup. But decided against it. Now those REALLY move the instant center to the rear.
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From: Downers Grove,IL
im very impressed and very jealous of your talent and tools you have available to you. good job!
I am only using a 115 volt 155amp Century Mig for a welder. I have a modest amount of tools and do it all in my garage. The tools used for this project was my mig, chop saw, drill, angle and die grinder and shop press. Heck I even used my home oven on self cleaning mode to help stress relieve the arm some after welding it - 880'F for 4 hours.
The Wife loved that!
here's a couple more pics of the cross member showing how it fits pretty tight under the car and bolted into the rollbar plate-
I also made some LCA relocate brackets for my Moser 9"-
Steve
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From: Downers Grove,IL
How many total hours do you have in your arm?
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I admire you for investing that much time in it. I, on the otherhand, do not have and cannot afford such time and would simply pickup the phone and order one.
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I admire you for investing that much time in it. I, on the otherhand, do not have and cannot afford such time and would simply pickup the phone and order one.
. as to the brackets, I made the shackles from the same 3/16" plate I made the LCA drop brackets from that are pictured above, those pics gives a little better sense of the thickness.
When you consider the entire stock t-arm is only about 1/8" thick stamped steel, then two 3/16" plates for the front pivot should workout I guess.
Steve
Originally Posted by kp
I'll measure the BMR shackles if I remember but they look like 3/16, I think Steve'e look thinner because they are bigger and not rounded off..
KP is that the Extreme or Track Pak????
Awsome job fabbing it up yourself......
Kyle