Drivetrain vibration and pinion angle

[Way2QWK]

Last weekend I went on a 600 mile road trip to drive "the Devils highway" more on that in another thread. Car only had 1800 miles at beginning of trip. I could feel some drivetrain vibes on the freeway around 80. Thought it was a combination of suspension mods, white line trains bushing and shifter bracket. half way into trip I started get some gear whine at 60-70 and vibration started to feel worse. Ended up putting cruise on at 70 and drove easy back home. Vibration was definitely felt under load but zero felt coasting. Figured pinion angle was off due to suspension mods. Measured it today and looks to 2 degree difference. Doesn't seem that out from what I gather from others. Need help here.

Mods..only 2,500 miles on car. 2014 track package.

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Steeda sport springs, Koni dampers, Bmr relocation brackets, pan hard bar, lower non adjust arms. Stock upper arm

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[Way2QWK]

Also I checked the pinion with the front on the ground and rear wheels on ramps.

 

[Way2QWK]

anybody have any ideas on what I can check or if that pinion angle is way off.

 

[DD2013 5.0]

With the stock rubber bushings still in place -2* isn't ideal. The rear end will "wind up" well into the positives. But without an adj upper arm it is what it is.

Pop the white line bushing back out and cut the bottom tab off of it. That will get rid of the vibrations.

With a drop more than about 1"-1.25" I'd look into an adj upper arm to correctly phase the driveline and lessen rear end movement with stiffer bushings.

 

[FocusSTGuy]

After I had lowered my car with K springs I had monster vibrations. I had to get an UCA and reset the pinion angle to get rid of it. It did not matter that it was close, the stock bushings were flexing like crazy. UCA is the way to go and it was really easy to install

 

[Way2QWK]

Thanks guys, needed others opinions before spending the money on an upper arm.

Whiteline bushing has been trimmed twice. Currently has the entire bottom piece gone. Not much reduction in vibes from complete.

What upper arm did you go with and are you happy with. How is increased NVH?

 

[lpheaven]

Thanks guys, needed others opinions before spending the money on an upper arm.

Whiteline bushing has been trimmed twice. Currently has the entire bottom piece gone. Not much reduction in vibes from complete.

What upper arm did you go with and are you happy with. How is increased NVH?

The whiteline bushing vibrates the living shit out of my Boss and its been "drilled out, trimmed etc". I'm pulling it this week, **** it, it's not worth that much vibration for the little benefit it offers.

 

[DD2013 5.0]

Interesting. All vibs with mine went away once I cut the bottom off the bushing.
I do had a UPR adj upper control arm tho.

 

[Way2QWK]

Just wanted to update this thread.....A few weeks ago I installed a BMR adjustable upper control arm(poly bushing). Happy to say that the freeway speed vibration is gone so far. Pinion angle is at 1.5' negative. No more adjustment on the arm turnbuckle to go any more negative but I dont think it needs it. Gear noise is probably ten times worse though, especially around 80mph.

I installed some dynamat in back seat and trunk to help lower noise. But haven't driven it to see if it helped. In the end all that matters to me is the vibration is gone now with the BMR arm. Installation on ramps in my garage was very easy. No nightmare like others had made it out to be.

 

[BMR Tech]

Try this.

Get the car on a level drive on 4-post lift.

Set the Pinion flange angle to zero.

Let me know if it gets better.