Silver Bullet 8150

iTrader: (1)

I have a spohn adjustable TQ arm bolted to a 9'' rear. do you want the pumpkin of the rear that bolts to the driveshaft to point up or down. i measured my rear where the tq arm bolts up and its at -2 facing up and the front of the driveshaft by the trans at -4......is that correct or no?


i tried searching and found no threads helping me with this.


thanks

mzoomora

iTrader: (36)

The rear should be pointing down when referenced to the trans. So if the back of your trans is -4 pointing down then your rear should be positive 1 or 2 pointing up, which would net you -2 or 3 pinion angle.

Silver Bullet 8150

iTrader: (1)

ok maybe it me but i dont get it, or im reading the angle finder wrong. im on the drivers side of the car looking under and im reading the finder at what i think is -2 or since im an idot looking at a clock 11:58...lol but the rear is up, shouldnt it be point down or am i completely lost?

mzoomora

iTrader: (36)

Depending on who you listen to you can do it different way. Some people will just point the rear 3 down in the front, but you should have -2 or 3 total when you factor in the trans. The idea is to have the driveline parallel under load, so if the trans is pointing down the rear should point up under load, or vice versa.

Edit- that is why it should be 2 or 3 degrees different, that is the amount you are expecting it to move when loaded.

Also, just because you measure a certain amount doesnt mean that the rear itself is pointing up or down because the ground is most likely not level. That is why you measure both the rear and trans.

mzoomora

iTrader: (36)

http://www.carcraft.com/howto/91758/

Other methods include measuring the driveshaft angle. You measure the driveshaft angle and adjust the rear until you get you desired pinion angle. This will assure you have the rear diff yoke at 0 , but does not account for the front u joint and does not make the pinion parallel to the transmission output.

mzoomora

iTrader: (36)

Also, look in the drag racing tech section. There has been a few threads on this with varying opinions.

Silver Bullet 8150

iTrader: (1)

ok thanks man

onfire

iTrader: (17)

https://ls1tech.com/forums/gears-axles/782847-we-me-my-friend-totally-hate-adj-sphon-ta.html

chrismorales75

You don't just point anything anywhere. The rear end or drive shaft may or may not point down.

You need to measure the angle of the drive shaft and pinion each time after you make an adjustment.

You can run between a total of -1 to -3 degrees of combined angle between the drive shaft and pinion.

Autos and manuals respond different to pinion angle.

A good starting point is -2 total degrees.

To do this you add the two values together. -1 degrees on the drive shaft and -2 degrees on the pinion would be -3 total.

So in this example the drive shaft would be pointing downward towards the rear end and the pinion would also be pointing down towards the center of the car.

If the drive shaft is +1 degrees and the pinion is -3 degrees it would be -2 total.

So the drive shaft would be pointing upward towards the rear end and the pinion would be pointing downward towards the center of the car.

So no matter which way the drive shaft or pinion is pointing the two should be -1 to -3 total when adjusted.

Like I said I would start around -2 total between the two.

If you have -2 and -4 you have too much negative angle, so you need to adjust the rear end up and that will also decrease the drive shafts negative angle, raise the pinion angle until the two added together are between -2 to -3, so that should be around -1 on the drive shaft and -2 on the pinion.