Custom Torque Arm
08-28-2007, 11:00 AM
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Custom Torque Arm Have any f-body owners tried to replicate an aftermarket torque arm at home, specifically those offerings from BMR? I’m switching to an LS1 T56 trans. and Ford 9” rear, and I’d like to build an arm that locates somewhere other than the transmission tailshaft. What are the advantages to running a shorter torque arm, such as BMR’s? If anyone has built their own, what are some of your material specs?
08-28-2007, 11:09 AM
#2
Most people do not because the aftermarket offers solutions for 99.9% of people out there. There are torque arm mount relocation kits that will get the mount off of the tailshaft and onto the cross member, there are the short arms, etc. etc.
It really isn't worth your time unless you just want to have the pride of having done it yourself. And there's certainly nothing wrong with that.
It really isn't worth your time unless you just want to have the pride of having done it yourself. And there's certainly nothing wrong with that.
08-29-2007, 12:02 AM
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Even professionally built torque arms break and most often at
the welds. I trust my welding for low stress hack-job stuff but
I wouldn't put my own work under my own car. Be sure you
have a realistic idea about your skill and knowledge. Material
specs are the least of it.
the welds. I trust my welding for low stress hack-job stuff but
I wouldn't put my own work under my own car. Be sure you
have a realistic idea about your skill and knowledge. Material
specs are the least of it.
08-29-2007, 07:29 AM
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Originally Posted by jimmyblue
Even professionally built torque arms break and most often at
the welds. I trust my welding for low stress hack-job stuff but
I wouldn't put my own work under my own car. Be sure you
have a realistic idea about your skill and knowledge. Material
specs are the least of it.
the welds. I trust my welding for low stress hack-job stuff but
I wouldn't put my own work under my own car. Be sure you
have a realistic idea about your skill and knowledge. Material
specs are the least of it.
08-29-2007, 10:51 AM
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What are the advantages and disadvantages of a shorter arm? I mainly want to build my own to work around the exhaust (long tubes, dual pipes), and the double-hump crossmember for the transmission. The BMR crossmember kind of gets in the way if I'd want to run two pipes all the way back. Are there particular aftermarket brands that have significantly more positive feedback than others? I know Spohn has a good rep with the Thirdgen guys.
08-29-2007, 11:37 AM
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The shorter the arm, the greater the torque reaction
at the axle. That means harder bite-down on launch
but also more chance of brake hop. For drag, great;
for street / road racing, probably want a more mellow
linkage setup (infinite length torque arm makes no
suspension reaction to wheel torque).
at the axle. That means harder bite-down on launch
but also more chance of brake hop. For drag, great;
for street / road racing, probably want a more mellow
linkage setup (infinite length torque arm makes no
suspension reaction to wheel torque).
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08-29-2007, 12:04 PM
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My car is mostly a drag car with a little street driving, so perhaps the short arm would be better.
Here's a response I got from a member on thirdgen.org:
"Length depends on power level and the height of the front mount. Shorter arms react faster, therefore work better for lower power levels. Longer arms react slower, thus are better suited for higher power levels. If memory serves me correct the BMR arm is roughly 48" and the factory is something like 54-56". Mine was 52, but the car would have been better suited to a shorter arm, as I had to run an excessive pinion angle to make it react fast enough to provide the needed traction. The BMR and Jegster short units are good for around 500hp, past that they become harder and harder to tune and become less tolerant to changing track/surface conditions."
Here's a response I got from a member on thirdgen.org:
"Length depends on power level and the height of the front mount. Shorter arms react faster, therefore work better for lower power levels. Longer arms react slower, thus are better suited for higher power levels. If memory serves me correct the BMR arm is roughly 48" and the factory is something like 54-56". Mine was 52, but the car would have been better suited to a shorter arm, as I had to run an excessive pinion angle to make it react fast enough to provide the needed traction. The BMR and Jegster short units are good for around 500hp, past that they become harder and harder to tune and become less tolerant to changing track/surface conditions."
