C Murda

iTrader: (24)

its an M6 car with a Moser 9" and longer PST aluminum DS....my car is also lowered on LG springs and i have the TQ arm relocation crossmember bracket and it is set to the highest hole (figured it made since seeing as my car is lowered so drivetrain moves up)
ive read a bunch of threads but everyone seems to say different things... ive recorded my rear pinion angle and DS angle accordig to the BMR video...my rear pinion angle i set to 2.5+ while my DS angle is at -4 which gives me a
-1.5 driveline angle. is this alright to have being an M6 car with a moser 9"?

before i had set it to this -1.5 (i havent yet driven it with this new setting) i had a slight vibration or bucking when cruising on the highway 65-80 mph...and my driveline angle was set at -3 (+1 for the rear pinion and -4 for the DS)

also i have read things such as my rear pinion angle should always face downward toward the front of the car making it a negative reading, is that true?

Intercooler2

iTrader: (24)

Yes -1 to -3 and you will just have to play with it to see

getusum

iTrader: (42)

had my car tuned last year...m6 cars should be around -2 and your tq arm need to be on the lowest hole not the highest....

C Murda

iTrader: (24)

Can someone just explain why it would need to be on the lowest hole seeing as when the body is lowered the rear end sits higher up in the chassis and that would make the nose end of the tq arm angle down towards the front? To me it just makes sense if I wanna keep the correct geometry I would have to raise the nose end up to stay with the rear?

C Murda

iTrader: (24)

man i hate reading all these other threads about pinion angle, driveline angle, true pinion angle....? what the hell am i supposed to be adjusting for? is "true pinion angle" the same as "driveline angle"? when people are just saying your pinion angle should be from -2/-3* doe that mean the actual rear pinion must read that or are they talking about the whole driveline relation (BMR method Rear angle+ Drivesaft angle= -2/-3 GOAL!)?

as i stated earlier my car is lowered on LG springs so 1.5-1.75" or whatever it is and with my car raised up as evenly as i can get it my rear pinion is pointing up 2.5* towards the front of my car (which everyone seems to say it should always point downwards) and according to BMR pointing up towards the front means its a positive 2.5*.
THEN my DS travels up 4* towards the front of the car and according to BMR if the DS goes up towards front that means the reading is a negative (-4*).....FINALLY like BMR says to do Rear angle + DS angle = "true pinion angle" in my case +2.5* + -4* = -1.5*...

now the biggest thing that is confusing me is how everyone seems to be saying that the rear pinion should be angled down towards the front and yet they have there -2 or -3 "pinion angle" while mine is angled upwards and im getting a -1.5? i know i just would have to adjust it to be a little less positive and i will get -2* but my rear end would still be in a positive upward angle????? can someone please shed some light on this?

EPP

iTrader: (22)

If you were to watch a car on a chassis dyno from the side of it, when a load is applied you can see the front of the rear end rotate up. If the front of the rear is angled down approx -2 degrees, under a load it will be somewhere around 0 degrees.

I copied the info below from BMR's website. I'd adjust it for a -2 degrees. Bob

Load the rear axle by either setting the car on the ground or letting the car rest on jack stands positioned under the rear axle.

Place the angle finder on the driveshaft and record the angle. The driveshaft angle is negative if it slopes downward towards the rear of the car. The driveshaft angle is positive if it slopes upward towards the rear of the car.

Now place the angle finder on the rear end torque arm mounting plate and record the angle. The rear end angle is negative if it slopes downward towards the front of the car. The rear end angle is positive if it slopes upward towards the front of the car.

Add the two measurements. This is your pinion angle. (Example: -2 rear end angle plus -1 driveshaft angle = -3 degrees)

C Murda

iTrader: (24)

^^^ you see i understand all of that and i understand how the tq load will want to rotate the front of the rear axle up hence why it seems as everyone is saying the rear pinion itself should be angled down towards the front BUT my problem is with the car in the air and suspension loaded my rear pinion is angled up towards the front with a measurement of +2.5* and then my DS is -4* for a total pinion angle os -1.5*. im getting the correct "final angle" after calculatio BUT why is it my rear pinion itself is angled upwards? that would mean under load it will want to rotate up even more and i dont understand how that can be safe???

z28ss4me

iTrader: (2)

Try putting the torque arm on the lowest setting and check the angle of the rear again. I'll bet you'll find you need to adjust the torque arm come up with the final reading of -2 you're looking for and the nose won't be rotated up as much.

C Murda

iTrader: (24)

^^ i had just considered that and went under the car to do it BUT...i can only go down one hole with the nose of the tq arm because my kooks ORY is right there IN THE WAY just like everything on these cars...theres always something in the way.. WTF. i just wanna know if it is bad that my rear pinion itself is angled up a degree or two? technically it shouldnt matter as long as my driveline angle or "true pinion angle" is within par -1 -2 -3 correct?