onefastmx5

So right in the middle of installing, I got a heavy case of the stomach flu. I Just slapped it together to get home to rest. In the 3 mile drive there was alot of vibration. The picture shows my setup http://s970.photobucket.com/albums/a...p.jpg&newest=1

Here are my questions- focused on the Yellow half circles.

1. Since my trans anlge is extreme at +4, can I shim the trans up with some washers between it and the poly mount?? I'd like it at 0 deg if I could.

2. I installed the TA on the "instant center" holes on the bracket for the tunnel mount. Does the angle of the bracket need to be 90 degrees? If it does, do I have to adjust the top eyelet bolt (instructions say don't touch it) to get the angle right?

Am I going in the right direction?

Thanks,
James

matLT1

In order to minimize vibration from the driveline you want the axis on the transmission output to be parellel to the input yoke on the axle. The parellel properties allow each u-joint angle to be equal thus cancelling vibrations out. You also want 2-3* of u-joint angle because u-joints will last longer with some sort of angle on them so the grease can be circulated. If you have 0* u-joint angle the grease will not circulate well. In addition, if you had 0* driveline angles when under WOT the rear suspension may deflect enough for the input yoke to create a negative angle (yoke actually lifts and pull shaft back slightly) and this is bad for traction.

onefastmx5

Thanks. After recovering from that nasty stomach bug, I put more thought into it. Basically, I need the Poly Mounts on the TA & mount to be 90* to the driveshaft. Also, I tried shimming the trans off of the mount- I got to +3, but my exhaust was on the body and rubbing.

Where I've gone wrong is reading about 0 and +1 as standard engine/transmission angles. So while I have +4, I don't think there's anything wrong with that. Actually, it may be a little better for weight transfer at the drag strip. I'll just set the pinion to +2 and that should result in -2 pinion angle.

UPDATE:
Readjusted the pinion angle and reset the TA bushing angle on the crossmember. No more vibration.
Negatives: There is a little more road noise and the faint gear whine from the s60 from 40-55 is amplified quite a bit now. Also, you can feel the gear lash (clunk) on quick accel or decel, since its no longer absorbed in a stock rubber bushing.
Positives: UMI makes a quality product. On the stock TA, under hard acceleration, I was getting massive shuddering from the rear of the car- that's now gone. Car hooks up immediatly now. The weight transfer feels much better. No more worries about breaking anything from the tailshaft on back when I hit the dragstrip. Time to buy sticky tires now