07_Turbo

Car has a moser 12 bolt with 3.73s has a race style arb and all heim joint suspension. Was told to set it to -6 and it just seems lazy out the hole. Everything is adjustable so point me in some direction guys

BMR Tech2

iTrader: (5)

Whoever told you -6, do not ever let them help you work on your car.
We normally recommend around a -2* angle on a rubber/poly bushing setup. If it is all rod ends, then -1 or 0* is good. Although, pinion angle will not affect suspension reaction much. It mostly only affects driveline vibration and u-joint stress. How are you measuring your pinion angle? Refer to this diagram to make sure you are properly measuring it

ThoR294

iTrader: (6)

So for our cars on the street, what do you recommend

BMR Tech2

iTrader: (5)

Around -2* if using bushings, -1 or 0 for rod ends/spherical bearings

ThoR294

iTrader: (6)

so if my trans is pointing down 3 degrees... i want my rear pointed up 1 degree? (i have bushings for my LCAs) im currently at 0 with a wicked vibration in neutral

BMR Tech2

iTrader: (5)

Correct. There should be 2 degrees of separation between the angles when measure from the same side. For ease of reading the angle, if you have a smartphone you can download an app called "Clinometer". It uses the flat edges of your phone as an angle finder and displays it in an easy to read format.

ThoR294

iTrader: (6)

I bought a digital anglefinder from amazon for ~$20. Worth every penny, way better than those analog ones lol. its got a huge magnet and it fits right below the output shaft of the transmission

BMR Tech2

iTrader: (5)

Where are you measuring your driveline angle from? There are not many accurate surfaces to measure from on the transmission itself. The measurement should really be taken from the output shaft yoke or the balancer/crank pulley. My personal preference is actually to remove the driveshaft and measure the pinion yoke across the u-joint cap mounting surfaces. Then measuring the crank pulley. This seems to be the most accurate.You can do it with the driveshaft in the car but you have to make sure you are measuring the pinion yoke correctly without the shaft/u-joint interfering.

MTN_Z

iTrader: (7)

Is the trans angle and axle angle measured in relation to the ground or another fixed point on the car?

ThoR294

iTrader: (6)

I was measuring it right here.

01ssreda4

iTrader: (96)

I had bad vibes at approx 90mph. I got around to measuring mine. First with the car on a level slab, I verified my subframe connectors were 0. They were. Then I backed on ramps and figured out the trans was at a 3° less angle then the subframes, actual numbers don't matter because the subframes are the new theoretical ground. So, my trans was pointing down. I checked my rear end and it was nose down. So I adjusted my torque arm to get my rear end nose up and matched the angle of my trans at about 1 less degree. Bam, vibes went away. If you find a theoretical level before lifting the car then you know where you stand once you get in ramps. As for measuring points, you want to measure on the u joint caps that are flat and on the flange side of things. Meaning as you roll the driveshaft, two caps will angle up/down as the shafts spin, the other two stay true with the trans or rear end. Also, use a socket of the appropriate size to get in in the cap and get an accurate measurement. Fitting a straight angle gauge on a cap is near impossible.

BMR Tech2

iTrader: (5)

Honestly, angle of the vehicle to level ground is irrelevant. You can set correct pinion angle with the car sitting on a hill. All angle finders reference to the ground as being "0" so technically when you measure you are referencing the pinion angle to the ground. HOWEVER, this is only to get a number to use as comparison. Even with the car sitting on a hill, if you measured your driveline at 33* in relation to true vertical, you would just adjust the pinion to read 31*. Thus leaving a 2 degree difference. It just makes the angles a little smaller and easier to manage.

MTN_Z

iTrader: (7)

That's the answer I was looking for. Thanks!

BMR Tech2

iTrader: (5)

This is not a good place to measure from. This is a cast aluminum piece, so all of the outer surfaces are inconsistent and have angles made in to help with mold removal. You need to be measuring from a machined surface such as the yoke, tailshaft itself, or the crank pulley. You may see 2-3* of variation just in measuring from a cast outer surface which can cause vibration, even if the comparative angle is measuring 2*

ThoR294

iTrader: (6)

Great info. Can I do this in my driveway with the weight on the wheels? I don't feel like driving to my uncles just to use his alignment rack which takes some ramps for me to get onto lol

BMR Tech2

iTrader: (5)

Yes, you can do it anywhere as long as the rear suspension is loaded. You can put the car on ramps, but we advise against jackstands since they don't load the suspension the same as on the wheels

ThoR294

iTrader: (6)

I have ramps. I will do that. Thanks!!!!!

01ssreda4

iTrader: (96)

I'm on the same page with you, however, with my car its near impossible to tell how things are angled once its on ramps. Knowing theoretical level is relevant so you get a better picture of what exactly is going on in your drive train. It helps you to know if your engine in pointing up or down and same with the DS and rear end. Once my car was in the air I honestly couldn't tell. Its just one more piece of info, plus, not everyone agrees with the same way for setting pinion and driveline angles so reference to ground angle may be relevant to some other way you may read.