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What is the difference between your Pro-Series and your Standard Duty torque arms?


Spohn Pro-Series Torque Arm vs. Spohn Standard Duty Torque Arm:

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What is the difference between our standard crossmember mounted torque arms and our Pro-Series crossmember mounted torque arms? We knew you'd ask, so here it is. We've been building crossmember mounted F-Body torque arms for over ten years. When we first started manufacturing torque arms most "fast" f-bodies were running 12's in the 1/4 mile. Then the LS1 F-Body was released and cars started getting in to the 11's. As more LSx technology came to market 10's and then 9's were becoming the norm. Fast forward to today and we have customers knocking on the 6's, some on drag radials (who would of thought?). Bottom line, our standard torque arm (and those like it) were never designed to handle that kind of horsepower and torque.

The 1982-2002 GM F-Body cars offer a unique suspension set-up in that they only have one ladder bar (torque arm) in their "stock style" suspension. The single torque arm prevents the rear axle housing from rotating. On a 3 link set-up the lower control arms locate the rear housing fore and aft and the panhard bar locates the rear housing laterally. Most cars (ie. G-Body, A-Body, B-Body, 79-04 Mustang, etc.) came from the factory with a four bar (4 link) set-up that spreads the anti axle rotation across four separate bars, and of course aftermarket race suspension systems like ladder bars and four link suspensions do the same. To keep a "stock style" suspension on an F-Body, this entire load is placed through one single torque arm.

What we have found over the years is that the weakest link in an F-Body torque arm is the pinion angle adjuster. If the pinion angle adjuster bends, once that link fails, the arm will twist up or snap instantly. There is no set rule on when you will overpower the strength of a 1.25" o.d. tube x 3/4"-16 threaded pinion angle adjuster set-up. We have customers running 7.X 1/4 mile times for several seasons with no issues. We also have had 10 second customers doing 8K RPM clutch dumps that have had arm failures.

Our advice would be that if you have an 11 second or slower car with an automatic transmission you'll be fine with the standard torque arm. If you're running 10.99 or quicker or have a manual transmission car with an aggressive clutch and do high RPM clutch dumps, then we recommend the Pro-Series torque arm system.

We designed our Pro-Series torque arm from a clean slate. We asked ourselves what it would take to design and build an F-Body torque arm that could stand up to a 6.0 second (sub 1.0 60' time) 1/4 mile ride, and the Pro-Series torque arm is the result.



Click on the thumbnails below to view full-size images
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1982-1992 GM F-Body                           1993-2002 GM F-Body

 

 

 




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Article Details

Last Updated
25th of September, 2011

Vehicle Application
1982-1992 GM F-Body, 1993-1997 GM F-Body, 1998-2002 GM F-Body

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