UCA adjustment question again

99SSls1

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I have read so many post on this and still I find myself questioning my set points. Driveshaft pointing down in rear so this is negative and my setting is -3.5. The rear end pinion is pointing down so this is also negative and my set point is -1.5. The car is a 11 gt500 stock ds with lca's and the adjustable uca. I checked the ds close to the rear end and the pinion on the small flat spot on the pinion by where the u joint is. I tried to keep it close to the 0 pinion angle but it left me with 0 and -4 which was not right.
Any thoughts
 

SCGallo2

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Measure your driveline angle on the crankshaft harmonic balancer (mine was -1.8* pointing down towards the rear of the car). I then measured on the rear end pinion flange and adjusted the UCA until I achieved 0*. My pinion angle is -1.8* with a full poly bushing rear and my driveshaft is happy, no vibrations. Your difference between the two angles should be -2.0 to -3.0* depending on the style bushings you have installed. Took me a while to figure this out also. FYI... stock 2008 UCA length is 8.5" center to center of bolt holes.
 
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Robert M

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Measure your driveline angle on the crankshaft harmonic balancer (mine was -1.8* pointing down towards the rear of the car). I then measured on the rear end pinion flange and adjusted the UCA until I achieved 0*. My pinion angle is -1.8* with a full poly bushing rear and my driveshaft is happy, no vibrations. Your difference between the two angles should be -2.0 to -3.0* depending on the style bushings your have installed. Took me a while to figure this out also. FYI... stock UCA length is 8.5" center to center of bolt holes. Start there and adjust your UCA as needed, but if your car is not lowered, you should be good right there.

^^^^Are you using a 2011-up UCA on your 2008? If not, the center to center on the OP's 2011-up UCA will be longer than the 2007-2010 UCA, both oem and aftermarket adjustable as shown below............

025_zps61c8f4e3.jpg


.......................................................^^^^^^^2011-up BMR UCA...........................................^^^^^^^^2007-2010 BMR UCA.
 
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SCGallo2

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^^^^Are you using a 2011-up UCA on your 2008? If not, the center to center on the OP's 2011-up UCA will be longer than the 2007-2010 UCA, both oem and aftermarket adjustable as shown below............

No I am not using the 2011 and up UCA on my 2008, thanks for pointing out the difference Robert. So it appears that 8.5" would not be a good starting point for his car.
 
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Robert M

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No I am not using the 2011 and up UCA on my 2008, thanks for pointing out the difference Robert. So it appears that 8.5" would not be a good starting point for his car.

Yes, I didn't want the OP to be confused when trying to set a starting measurement of 8.5" on his 2011 while scratching his head and thinking, "This isn't working out?!?!".

The BMR 2011-up UCA/UCM is a nice upgrade for the 2007-2010.


R
 
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99SSls1

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Measure your driveline angle on the crankshaft harmonic balancer (mine was -1.8* pointing down towards the rear of the car). I then measured on the rear end pinion flange and adjusted the UCA until I achieved 0*. My pinion angle is -1.8* with a full poly bushing rear and my driveshaft is happy, no vibrations. Your difference between the two angles should be -2.0 to -3.0* depending on the style bushings you have installed. Took me a while to figure this out also. FYI... stock 2008 UCA length is 8.5" center to center of bolt holes.

Well all I have read says with a 2 piece ds to measure off the back of the ds. Measuring off the crankshaft balancer is news to me. Now I am really confused but it seems good with no vibrations. More research I guess unless someone else responds. Until then I'll check the balancer.
 

SCGallo2

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Reading the driveline angle at the balancer is the same as reading it from the transmission output shaft, but the installed driveshaft will prevent you from getting an accurate reading at that point. This is the simpliest way to get an accurate reading without removing the driveshaft. You are looking for -2.0 to -3.0* difference between angles measured at the output of the transmission and the rear end pinion flange, regardless of what driveshaft you have installed - one or two piece.
 

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