98TADRIVER

iTrader: (36)

i bought a UMI chassis mount tq arm w/ DS loop not too long ago

I recently got myself a fully optioned moser 12 bolt rear as well
also added a LPE 3.5" aluminum Driveshaft . both were purchased from a very good friend of mine

i went on this site http://www.streetissuecustoms.com/pinionangle.html

and I understood how to set it up, front on ramps, rear on jackstands, vehicle level, took my magnetic angle finder etc. the face of the crank pulley was reading -5 degrees so i set the rear @ +5 degrees so it is now at 0 pinion angle. there's 2 holes for the front of the torque arm to bolt to, i chose the lower of the 2 holes. (thats for instant center i believe) my DS loop and torque arm mounting bolts dont appear to be hitting the driveshaft (no signs of wear or shiny ring around driveshaft

but im having a few minor issues-

Vibration, and a light clunking sound too

The vibration is consistent with my speed, usually loud around 85 mph, and going on all the way till i feel like letting off. the vibration is pretty annoying, for it rattles the change in my center console.

the u joints were just replaced in the DS before i recieved it

the clunking noise isnt too loud, usually hear it at low speed (5-10mph), usually when i step on the gas or hit the brakes, (like coming to/leaving a stop sign or traffic light)but annoying nonetheless. if thats normal, i can live with it.

i never noticed all of this until i installed the torque arm, back when i had my 10bolt in it did the same thing as it is now.

is the vibration caused from the harder bushings and being mounted directly to the chassis?

all help is appreciated. thanks!

jdustu

iTrader: (2)

the clunking is going to be normal for a chassis mounted t/a. i've got the spohn t/a, and by playing around with the tightness of the front bolts you can get the clunking to lighten up, but it seems to be the norm that there will be some noise.

there was a good article in the "what's your problem" section of carcraft this month(july 2007) about vibrations at speed. i tend to get a lot of harmonic noise as i start hitting higher speeds, so this article made a lot of sense to me: if your trans and rear pinion are at the same height, you'll get harmonics....you want them to be parallel but not on the same plane....this is the pic they use from mark williams:


i might try to add a spacer to move the trans up in my lowered car, i want to see if i can eliminate some of those harmonics.
-josh

98TADRIVER

iTrader: (36)

thanks for the pic and the info, i understand. now its just trial and error now lol