scites

iTrader: (30)

tried to set my pinion angle via BMR's web site. when my pinion angle reads -5 my D/S reads +5 which equals 0 so if i keep cranking the D/S angle seems to stay the same as the pinion angle..IE if the rear is -7 the D/S reads +7 and pretty much the best i could do was a -1.5 maybe..but she is vibrating like shitty under 40mph..help me out im confused..thanks, Tom

junior28570

iTrader: (22)

Yeah, it can be a little confusing.

+5 + -5 = 10 degrees total (BAD). If you simply count the degree marks between the 2 measurements, you'll find your total.

Think of it this way .. 0 would represent a straight line between the pinion and the driveshaft. You want the sum between the 2 angles to read what you're looking for (A4 somewhere between 1.5 and 2.5) Since your transmission is obviously higher than your rear, it should read +. So your pinion going to read -. EX. +1 + -1 = 2 total degrees of pinion angle.

1QUIKWS6

iTrader: (61)

Directly from BMR Adjustable TA instruction:

9. Set pinion angle using the following method:

• Make sure the rear end is loaded by either setting the car on the ground or letting the car rest on jack stands positioned under the rear axle.

• Place angle finder on the driveshaft and record the angle. Now place the angle finder on the rear end torque arm mounting plate and record the angle.

• Subtracting the two results in your pinion angle.(Ex: -6 rear end angle subtracted from +4 driveshaft angle = -2 degrees)

• Turn adjuster to achieve the desired angle.

• As a starting point, most F-Bodies seem to like the following initial settings: Automatics: 1-2 degrees negative Manuals: 2-3 degrees negative

10. Once pinion angle has been set, tighten all jam nuts and rear bracket cross bolts.

junior28570

iTrader: (22)

I should clarrify a few things so as to not mislead. The perfect scenerio is the car is perfectly flat in reference to the Earth. Gravity is the only constant since your car could be at a rake/slope/slant (ie. as being parked on a hill. up or down). So, 2 negative numbers are possible as are 2 positive numbers. So long as the difference between the 2 numbers is within the 1.5 to 2.5 degrees. Ideally you would want your car as perfectly level as possible and weight in the car to represent yourself.

Captain InsaneO

iTrader: (38)

Here is where I'm confused.. you said " +5 + -5 = 10 degrees total (BAD)." Which indicates you add the two numbers together, but BMR says to subtract those numbers.

• Subtracting the two results in your pinion angle.(Ex: -6 rear end angle subtracted from +4 driveshaft angle = -2 degrees)

Shouldn't it be +5 - -5 = 0 according to your example?

Brewski

iTrader: (1)

The math equation throws it off a bit... They're talking about the total number of values in the range of 5 <-> -5. So from the example posted before "EX. +1 + -1 = 2 total degrees of pinion angle." You'd have 1, 0 ,-1 in that range of numbers so you'd 2 degrees from the other number in that range.

Doh see what you're questioning: The BMR dirrections seem to imply that a condition of -5 rear end angle and +3 driveshaft angle would be in the sweet spot for an A4 rather than being a difference of 8 in the range.

camarojunky74

iTrader: (14)

not sure if this was emphasized, make sure you make these adjustments on a drive on lift,

GregWS6&z28

iTrader: (8)

it's easier to look at it like this:
subtract rear end angle from driveshaft angle
so, (Driveshaft angle (-) Angle of pinion = working pinion angle)
to make the numbers easier convert them all to 90degree numbers so there's no -3 and +3 etc.

if the driveshaft is pointing to 87 degrees note it as that. If the rear is going positive past 90 degrees say to 1 or 2 degrees, then note that as 91 or 92 degrees.

so if you have an angle of 87 degrees driveshaft minus 91 degrees pinion then that = -4 degrees of negative pinion angle (pinion turned downward)

hope this helps

camarojunky74

iTrader: (14)

call jerry at umi, he's good and helped me on this couple weeks ago when setting mine, just tell him you got a umi arm lol

GregWS6&z28

iTrader: (8)

also it wouldnt matter if the car was on a drive on lift or the back wheels were on rhino ramps. the front wheels end up being the piviot point and the angles will change accordingly.

scites

iTrader: (30)

i just crawl my fat *** under the car on the garage floor..

camarojunky74

iTrader: (14)

lol, my car is so low i cant get a jack under it, i bought the umi torque arm and i bolted it up, and had my angle perfect in less than 5 min's just like 3 turns to get perfect

Captain InsaneO

iTrader: (38)

I went ahead and already did that. He was a great help, along with all the replies. It makes perfect sense now.

camarojunky74

iTrader: (14)

yeah, im glad to hear, he's a very knowledgeable guy, explained it to me very quickly and i have no vibration what so ever