1992 Camaro ZZ4 TPI T56 lowered 2" eibach pro kit. Bilstein Shocks. I brought and installed a spohn adjustable torque arm that mounts to the trans. cross member. I ordered it with the del-sphere end. Spohn said its the best of both vibration and flex. I got the angle indicator and adjusted it. The car vibrates from 2000 rpm up. Every time you shift it starts all over again. I thought I had it wrong. So I had the pinion angle adjusted at a local dealership that has a drive on hoist. Still nothing changed I also had a 2nd shop look at it. I was told everything was adjusted correctly and the vibration is expected. I called Spohn with my problem and was told its my driveshaft. I had my drive shaft balanced at a local machine shop. Still no luck. If I put my stock TA on the car the vibration is gone. WTF I thought the cross member mounted TA was the way to go. Anyone have this problem if so please would love to know what was done to solve it?

 

So only the torque arm and crossmember were changed?

A rubber bushed torque arm has no negatives. Even a 0.25" vertical deflection at the forward bushing would have basically no pinion angle change.

It's the tailhousing mount that's an issue.

Right now, you need to change to a rubber transmission mount if you're rocking a poly. It could help.

But, you need to clarify when the vibration occurs. If it truly is dependent on engine speed, that points to an engine balance issue, flyhwheel perhaps.

How many miles are on the swap? When was it vibration free? Did it ever work right? What's been changed since?

And: Which T56? LT1 with OEM style flywheel? Did you use the right pressure plate bolts? Or: LS1 against adapter plate against thirdgen bell? Or, something else?

Lots of holes in your question.

 

My guess. Check the following link:

https://www.thirdgen.org/forums/tran...ison-pics.html

JamesC

 

if it is based from rpm and not mph, it sure sounds like something coming from the motor or input shaft side

 

Gotta be something in front of the clutch.

See my signature for some mental organization help.

 

I have a poly transmission mount. Never vibrated until I installed the Spohn cross member mount TA. The car has been lowered for 8 years every bushing has been replaced with poly. All that was done a long time ago never had and vibrations until I put the Spohn set up on the car. If I put the Stock tail mount TA with a poly bushing it doesn't vibrate. This was the last thing done on the car until this it never vibrated. (Transmission is a Richmond Retro fit T56)

 

two things been down same road as you with spohn TQ arm setup in my case I had rubber engine mounts and poly trans mount that was the main vibration issue went to poly engine mounts and poly trans mount most vibration was gone also using a digital angle finder I went to neg -4.5 degrees pinion angle and ALL vibration gone..DO NOT use stupid plum bob thing that comes with tq arm it is usless never got it correct

 

definitely use a digital angle finder, driveline angles can be very difficult to get right.

it sounds to me like it isn't set correctly. after chasing the same problem myself last summer. you need to get it dialed in better.

 

Oddly enough, Mine has a strange Kinda Vibration/growel also after upgrading the rear with new torque arm and all rear end linkages All Polly. only comes on during acceleration and squatting thru a dip in the road makes it more pronounced. I cant figure it out either. You can feel it in the seat. Would really like to see if we can figure it out.

 

Thanks for the insight in to this. I still have the car in storage. Hoping to get it out in May sometime. I will have to buy a digital angle finder and try a go again. Will post if resetting the angle fixes it. (will post either way)

 

Just wondering what digital angle gauge did you use a model and manufacturer would be greatly appreciated. Thanks

 

this is the one i have:

 

If it doesn't do it with the original mount its the Spohn torque arm.I had the same problem. My camaro shook unbelievably with the Spohn setup .I took it off and it is fine now.