New Torque Arm Design
 

I've been working on a new Torque Arm design for my F body. I currently have a Moser 9" housing with the cast torque arm mount and a Spohn adjustable torque arm. The casting and the Spohn stuff is extremly heavy. All those pieces parts went a whopping 56# on the scale. I have also been a bit dissapointed in the current Torque Arm setup in that it has way too may connections that generate slop. There's 1) the connection of the TA to the Moser casting with the tie rod bolts, 2) the heim joints to the Spohn attachment bracket, 3) the front short link bar to to cross member, 4) the urethane end link to the link bar. All of this makes for one system with tons of free play. Couple that free play up with the slack in the Detroit locker and you've got one huge noisy clunking mess. My goal was to eliminate unnecessary weight and eliminate multiple connections. My new TA design eliminates the Moser casting. The TA bolts directly to the 3 threaded Moser mounting points. The new design eliminates the Spohn link bar and uses a BMR style urethane 1.25 ID TA bushing in a Crossmember mount. This still gives longitudnal freedom for the TA but the TA end is held firm in the vertical and horizontal planes. There's nothing to clunk. I have eliminated and pinion angle adjusters and set my pinion parallel to the crankshaft centerline before making the final welds in the TA to mounting plate. I'm not a believer that pinion angle has anything to do with traction anyway. I think the new design has all the advantages of the chassis mount Torque arms but eliminates the downsides. The new design eliminated between 20# and 25#. That's huge in my book. I currently have some street miles on it and so far it is great. Time at the track will tell if I've gone too far on the weight reduction. Being an M6 car, I'm pretty abusive on drivetrain and chassis stuff. If it will survive my launches, It will be good for 95% of the drag racers on this board. I'll shoot some pics this weekend. Maybe it's something Spohn or BMR should consider for those Moser 9" racers.

Steve

Re: New Torque Arm Design
 

So basically you built a beefed up stock torque arm. It has no way of adjusting pinion angle or instant center. These both play alot into the way a cars suspension will react.

Re: New Torque Arm Design
 

Pinion angle was set before final welds were made. No way to make further adjustments after that. It's not even close to a beefed up stocker. It no longer mounts to the transmission and no longer uses the heavy Moser torque arm adaptor casting. I used the typical 1 1/4 OD X .120 wall DOM 1026 tubing.

Also,

There is really only two ways to significantly change the IC on a Torque Arm suspension.

1) Change the angle on the lower control arms
2) Shorten or lengthen the Torque Arm ( Moving the endlink point up or down doesn't really change IC very much)

I'll try to snap a pic or two this weekend.

Steve