STEEPSS

iTrader: (30)

I went from a 3.70 gear to a 4.30 gear
stayed with 31 spline detroit soft locker
changed from 4" 1330 pinion yoke to 5" 1350 pinion yoke
went from stock driveshaft to used pile of **** denny's busted *** "nitrous ready" driveshaft
moved rear end ~1" forward to accommodate for 28" slicks
went from busted *** driveshaft to PST aluminum driveshaft (measured for after rear was moved)
replaced extension housing bushing


I'm all BUT 100% sure that when I moved the rear forward that 1" forward, it took the working angle of the front U joint to an extreme that when it hits 80 MPH (XXXX rpm) it starts to get silly.

It'll be a while before i'm back around the car to further investigate, but so far, spacing the tranny x member down is the only thing that has made any difference, besides replacing the denny's driveshaft with the PST.


see--------------> http://www.vibratesoftware.com/html_...aft_Angles.htm

95 TA - The Beast

iTrader: (2)

Ok, so, basically, a 9" is the WORST solution for our cars because of the extreme pinion angles that result from running one... Thanks for that clarification...



Honestly, I hate the idea of a 9" rear end... always a hack... S60 or 12-bolt is the only way to go...

STEEPSS

iTrader: (30)

a hack?

I don't hack anything.

jmd

iTrader: (4)

Yes and no. It sounds like driveline angle is the issue. While the difference in angle from the foreward and rear u-joints can be incorrect for operation, a stock or slightly lowered F-body isn't going to be putting "extreme" angles on things.

You're going to make someone who reads this think that. :o

Mikey 97Z M6

iTrader: (37)

LOL,,, thanks for the laugh. I needed that.

Mike

studderin

iTrader: (28)

another thing you said was the DS was tight to install. did you think about moving the rear end back maybe only 1/2 (reset pinion angle) and see if that helps? The DS slip yoke might be bottoming out. That was something you said you changed (move the rear end fore word) then the vibration started.

cool shimming the Xmember down helped.

oh I forgot to tell you my hood is painted now.

STEEPSS

iTrader: (30)

Ok. it's not necessarily an "extreme" angle. Its just out of the tolerance for the RPM's that its turning. ... I believe.

I thought about that, but it doesn't matter if its under acceleration, (even though when you accelerate and load the suspension, the drive shaft actually moves to the rear, and out of the trans. if you hold it at 90+ it does it, regardless.

And correct on moving the driveshaft forward. However, I measured for a new driveshaft after the rear end was moved. SO, according to PST, it's the "correct" length.

Sweet on the hood!

STEEPSS

iTrader: (30)

FML. I've messed with this every weekend, and still no end in sight. I guess I'll be pulling the third member here in a couple weeks the next time I'm home.

My working angles are <2* front and rear, and <.5* difference between them.
Pinion angle is -1*

It moved my vibration up in the MPH range by correcting my working angles, and decreased it, but it did not fix it by any means.

Vibration is persistent. I just emailed a couple sponsors, so we'll see if they have any more insight into this situation.