I had the car up in the air today to swap out the existing 3" driveshaft for another (oem) 3 1/2" unit I picked up from a friend. The OEM unit was the exact same length as the existing one which I had built locally for the car years ago, and I was pretty sure the existing 3" unit was going beyond it's critical speed limit. Although the charts said it should've been good for ~4700 rpm, I never got it that far. The highest I've had it up to was just over 4000 in 4th gear.
The OEM shaft didn't appear to make any appreciable difference in the vibration levels--as soon as it got to ~4000 it started to vibrate.
I reinstalled the 3" shaft and decided to video the rear tires to see if I had a wobbly rim or an out-of-round tire.
Here's the first video:
http://vid33.photobucket.com/albums/...psl8qdnrez.mp4
The second video of the drivers side was too dark, so I re-shot it. As soon as the tach hit 4000 in 4th, all hell broke loose.
http://vid33.photobucket.com/albums/...ps73g92xhw.mp4
Part of the aftermath:
I am within a whisker of throwing in the towel at this point. I have fought tooth and nail to get this car de-bugged, and as soon as one issue was resolved another came up. I now have a <span style="font-weight: bold">VERY</span> expensive hunk of garage art sitting on jackstands with a wasted trans, a wasted exhaust system from the X pipe to the mufflers, and who knows if the rear end got hurt, I haven't checked that yet. The floor took a hell of a beating as well, but again I haven't mustered the courage to crawl back under the car again and assess the severity of the damage.
And to top it all off, I'd just made phone calls today to inquire about having a new driveshaft made for the car. Due to the length (60" center-to-center) everyone said either 4" aluminum--which there wasn't room for under the car, or 3 1/2" carbon fiber--to the tune of well over $1K. There's no way I could swing that right now, while desperately trying to get my father's old house into marketable condition which is quickly bleeding me out.
Sure wish I would've video taped the driveshaft first--I was going to video it right after the drivers side rear tire.
Somebody please wake me up, this has to be a bad dream.....