Mk4: alignment between IRS/pumpkin and TKX tailshaft

[Grubester]

I have concerns about the offset I'm measuring (w/Klein digital level):
With the 4" frame tubes level to the ground, I measure 1.6 deg "down" for the flange on the IRS pumpkin. And with the engine centerline level, the center of the tail shaft is 1" higher than the center of the flange on the pumpkin.
This would seem the driveshaft's universal joints are going to be working too hard. But is that true?
Note: I measured the level condition of the "engine centerline" using the front crankshaft pulley.

[rich grsc]

:rolleyes: normal. The driveshaft should not be straight or level

[Grubester]

Yes, 'rich grsc', but where's the limit? That's the thing I have no experience with.

[gbranham]

I agree with Rich. I put three of Forte's spacers under my TKX w IRS, eyeballed the driveshaft ujoints, amd they didn't look to be extreme angles, so I called it good. I know I've in no way given you empirical data, but this just wasn't something I was worried about. I think folks get a little too precise with these angles.

Greg

[TXeverydayDad]

This is one of these things that can drive you nuts! With a pinion angle (difference between the Tkx tail shaft and the pinion (connecting surface on the IRS)) less than 2* and relatively similar operating angles of the 2 joints (between tkx-drive shaft and drive shaft to pinion) you’ll not have any issues at all. Yes, you can optimize and chase vibration sources forever, but I doubt this will have much impact.

Disclaimer: I’ve not driven my roadster yet, so it’s still all theoretical for me.