Stangkilr

iTrader: (47)

Okay, this might be a dumb question BUT my angle finder does not tell me which is which. What side is the negative side when its setting on the rear-end? This is the way it is when setting on the rear end. Is the way I have the pos/neg correct when upside down?

BMR Suspension

iTrader: (6)

When you are viewing the rearend from the driverside of the car and have the angle finder facing you, looking at the top of the angle finder, to the left of zero is negative meaning the driveshaft is running down from the transmission.


When you take an put the angle finder on the rearend viewing it from the driverside of the car looking at the top of the angle finder, to the right of zero is negative meaning the rearend is pointing down. Hope this clears it up a little for you.

Lee Spicher
lee@bmrfabrication.com
(813)986-9302

OldeSkool

Doesnt matter

Adjust so that the needle points to the exact same spot when you put it on the DS as when you put it on the pinion. Then you'll have the ideal (for street car) 0* pinion angle

If you Feel that you'll actually go severely positive under launch (unless you're a serious drag racer this wont happen) and you must go negative.. just figure out which way turning the adjuster causes the pinion to move down- you can tell by looking- and turn the adjuster and check the measurement until there are 2 marks(or however many degrees you want) difference between them.

SS1156

iTrader: (4)

Ok here's a question. I installed a Spohn TA and did the angle and mine is set at -2.5, which the guy told me was the right setting. I have noticed since then I get a horrible groaning (the best way I can describe it) once I reach around 70mph. I'm thinking the pinion angle is off? Any suggestions Lee? I'm soon going to be getting rid of this TA for a BMR with the relocation bracket. Since my car is lowered and I have speed bumps, they just installed, on my street, I need something that isn't so low. I'll be posting that once the BMR one is in.

OldeSkool

because a negative pinion angle isnt for street driving. theres no need to have anything other than 0* for a street car.

A dedicated track car... maybe you might go with a negative pinion angle, but thats it

A negative pinion angle on a street car wears out the pinion and generates noise

BMR Suspension

iTrader: (6)

It sounds like the pinion angle is not correct in the car which is causing the groan as you describe it. I will out of the office until Monday but I can be reached then to see if I can help you out

Lee Spicher
lee@bmrfabrication.com
(813)986-9302

BMR Suspension

iTrader: (6)

An absolute zero degree angle on the u-joints doesn't allow the needles to rotate in the cups and they will eventuallt flat spot and fail. It takes very little angle to make them rotate properly but no angle difference at all I don't recommend.

Lee Spicher
lee@bmrfabrication.com
(813)986-9302

Stangkilr

iTrader: (47)

Im confused but ill listen to the man that works at BMR lol. My car just vibrates and I get a horrible groaning like said above around 70mph. What I also dont understand is I put a stock 10 bolt back in my car so I set my adj. LCA's to stock length but my rear end sets way back towards the rear bumper. Im just tired of working on my car, I wish I had an LS1tech style speed shop near my house. I would just drop it off and let them **** with it. I like my cobalt, it drives good everyday and never breaks lol.

SS1156

iTrader: (4)

I'm gonna get my car up on the lift and adjust the pinion angle this weekend.

pmbmax

I agree .

revtime

iTrader: (1)

If they are adjustable LCAs then just adjust them to center the tire in the wheelwell.
I also agree with Lee on the 0 pinion angle. I lost a DS some time ago and I believe it was due to having zero pinion angle.
The Cobalt is fun and won't leave you stranded but its just not that fast now is it?

OldeSkool

Centering the wheels in the wheelwell isnt the best way to adjust the LCA's

They should be adjusted on an alignment rack to make sure that your thrust angle isnt off. Even stock cars are known to have thrust angles that are wildly off.

revtime

iTrader: (1)

I will admit thats the best way but if they were off and you had it aligned wouldn't your wheel/tire combo not be centered in the wheelwell while being perfectly straight?
That would suck.

OldeSkool

center the wheel in the passenger side wheel well and then adjust the other LCA so that the axle is square in the car (0 thrust angle) and if the passenger side isn't at least reasonably close to being centered as well.. then something is wrong with the car.