4 replies to this topic

[mbican]

My 1990 Miata had vibration, removed driveshaft and u joints felt sticky. Purchased new shaft with replaceable u joints and found it to be larger and heavier than the stock one. My car will never win a race when I ever get around to racing it after a couple years of HPDE events but was wondering if extra weight would adversely effect performance.

[Ron Alan]

Rotating mass! In theory it all adds up right? But I wouldn't worry! 

 

Surprised you couldn't find an OEM piece(used/junkyard) that felt ok...I've got a pile of these in my shed! Cant hardly give them away! They do wear out/go bad but not real common...at least in my experience.

[Justin Casey]

Vibration? Check your motor and differential mounts. You'll notice a lot of slop between shifts. 

 

+1 from what Ronald said too. 

[mbican]

Vibration was the driveshaft, got the new one cheap enough, was concerned with used ones going bad. Not finding any Miatas in bone yards around here.

[Steve Scheifler]

Although non-ferrous driveshafts are something checked for in tech, I suspect primarily because it's a simple test with a magnet, the potential gain/loss for our purposes is minuscule. Refer back to the flywheel weight discussions and calculations from a year or so ago, then divide by about 10. That said, I have a brand new aftermarket driveshaft which is a bit heavy, so I've never used it.