I just put some SFC's and a track pack on and my car vibrates like crazy now at 80MPH. Could this just be a bad pinion angle setting, or something toutching the DS (God I hope it's not the DS loop). I set the pinion angle at -1.5 which is very conservative for an M6. Any ideas would be appreciated. Thanks.

 

I've had vibrations at high speed due to pinion angle being off, so yes it could be. I'd recommend setting it to zero, to see how it feels at that point. Then you'll know whether this issue is related to pinion angle. Then double-check your measurements on pinion angle, -1.5 degrees like you say shouldn't be a problem...

Dave

 

Ok, I reread the instrucions on my SFC's, and it said that I may have to torque the LCA bolts to 90 ft lbs to compress the reenforcment bracket enought so that you don't get clunking and rattling. So I have compressed it to 80, and then to 90 then to 95. It helps alot, but they said 90 ft lbs. I emailed BMR yesterday but have had no response yet. Any suggestions?

 

Make sure you are measuring the pinion angle correctly, the angle finder needs to be parallel the pinion, make sure to scrap off dirt and grime.

 

after rereading your post I am thinking you overtightened your u-joint sraps and thats your vibration, you will probably need a new u-joint, I forget the torque specs but its something like 2-25 ftlbs, its a good idea to use blue loctite and not to crank them down.

 

How about using a washer on the inside instead of overtightening them

 

Is the rear u joint of the driveshaft installed correctly in the straps? Is it contacting the TA hardware? It should be obvious if anything is contacting the ds, there will be scrape marks on the ds.
Even if there was not enough torque to compress the LCA mount (which I doubt) it would not cause vibration.
Did you set pinion angle with the weight of the car on its tires?

 

I set it with the suspension loaded, no weight on the tires. Is that just as good?