Optimum driveline angles for vibration free high speed operation.

[TheJDMan]

Here's my dilema. I replaced my old ST10 with a new T56 Magnum in Dust Off and since that time I have been fighting driveline vibration at hiway speeds. The driveshaft is a new unit from Strange so I have to believe it is balanced correctly. My crankshaft angle is 3.30 deg down to the rear. I adjusted the pinion to 3.30 deg up to match. The driveshaft is angled up 1.50 deg to the rear. This results in a working angle on the U-joints of 3.30+1.50=4.80 deg. I am pretty sure this is too much working angle. Since I have the G-Link rear suspension I can easily change the pinion angles and ride height but the crankshaft angle is not as easy to adjust. Just for a test I adjusted the rear coilovers up to raise the rear of the car about 1" in an attempt to reduce the driveshaft angle to near zero. A short test drive resulted in dramatically reduced driveline vibration but not completely gone.



I currently have the engine/transmission out of the car to fix a nagging oil leak and so I can massage the firewall and tunnel for about 1/2" more clearance. I also have to do some fabrication on the crossmember to raise the mount location but my question is what is the optimum crankshaft angle I need to shoot for? I'm thinking about trying to get the crankshaft angle to about 2.50deg but I'm hoping Ron has some drive line setup advice for high speed vibration free operation.