My '88 IROC-z now has an LS3, T56, and a 12bolt. It has a non-adjustable BMR torque arm now, but I have heard that they often hit the transmission tunnel. My noise sounds a lot like the springs are bottoming out. I was wondering if anybody knows of a different torque that fits better or does not hit the trans tunnel? Any pointers would be appreciated.

 

I'd put the car on jack stands and use a floor jack to lift the rear to normal ride height. Look around for possible interferences. The tunnel sheet metal is really thin and torque arm leaves quite a mark if it hits.

The most likely place of contact is the bracket that attaches to rear axle. That can dig into the tunnel if the car is lowered a lot, or the pinion angle is set nose high (improperly). The rest of the torque arm usually has good clearance to tunnel.

It's very possible the axle is hitting rear snubbers if the car is lowered. It doesn't make a loud noise though if the snubbers still have structure. It just makes the car ride lousy and causes tires to spin during acceleration.

 

Sometimes the contact point is obvious.
And very loud when it occurs!



That's an adjustable UMI arm on a Dana 44. Chassis is an 86 Coupe that's been lowered a 1-1/2" to 2".

 

Had to take a hammer to the same area when I put in my 9", luckily I didnt get to the point you did

 

Well, one thing I can say about the result is that it was self clearancing!
After the initial hit, I tweaked the adjustable panhard arm a little and drew the axle to the passenger side slightly. It may have been even more centred when I was finished. As for the gash, I trimmed up a piece of sheet metal to fit the hole and tig'd it in place. A little paint and it disappeared.

 

yikes,
i guess I got lucky that mine only left the slightest scuff mark in that exact spot. I guess I had the PHB adjustment pretty close, but one day I was under there and I noticed the scuff on the paint so I knocked a little more clearance with a hammer and I have been good ever since then.

 

No problems, here. I'm using the BMR trak pak with a Mark Williams 12 bolt. Fitment up front was tight, but not in back.

 

I have an 8.8 rear in mine and an adjustable BMR torque arm wouldn't work. My car is lowered and the arm was hitting everywhere. I now have an UMI arm on it and its much better but it still treats the transmission tunnel like a 2 dollar ***** on nickel night every time I drive it.

 

" it still treats the transmission tunnel like a 2 dollar ***** on nickel night every time I drive it.[/QUOTE] "

classic..2 dollar ***** abuse at its finest

ive got the umi torque arm with the trans mount/loop and its noisy as hell too but i need to drive it a bit more,and a lot harder in order to do some automatic clearancing as well.*** end of the car isnt too low YET but it will be seen enough however this is with a lowly 9 bolt rear