BMR Rear Suspension

[MattR]

2011 with adjustable pan hard, adjustable lowers and upper link. Basically the Revan Racing package. After installing the Ford Racing L springs I took the car in for a 4 wheel alignment. Now my tires seem further back in the wheel opening. They also said they set the pinion angle to +2 and Ford specs are 2-4. Everyone on here uses -2, when I questioned them they said it would drive my rear tires further back causing rubbing to make the angle more negative. Car drives smooth up to 120. Can things be adjusted to move the axle forward and still have good angles? Right now the rear axle is perfect side to side and thrust angle is zero.

 

[Catmonkey]

I believe the only way to move the axle forward in the wheel wells is with adjustable lowers, if the pinion angle is adjusted properly.

 

[MattR]

I do have adjustable lowers. I'm guessing they found it difficult to adjust the upper and used the lowers to set pinion. I can only fit my pinky finger between the tire and rear factory mud flap. So much for the best shop in the area.

 

[enormous]

What size tire are you running in overall height?

 

[MattR]

29" its the 315/35/20 NTO5R. Anyone know of a good shop in Michigan that can set this up for me? I already spent a half day and 2.5 hours of driving to get what I think is a poor set up. That and I have not seen an ounce of traction increase since adding all these parts. The DR's helped a lot but so far other than centering the rear axle for tire clearance I haven't gotten anymore bite. I might be at 520rwhp and can still blow the tires off in first and most of second with the TC on.

 

[Catmonkey]

Did you install relocation brackets to move the pivot point on the axle lower? That's a must on a lowered vehicle to improve the instant center for better traction.

 

[MaximumVelocity]

That bites. The lowers should really only be adjusted to set thrust angle, not pinion angle (like you said, that's the UCA). Take a stock lower so the next shop can adjust the BMRs closer to the stock length.

 

[MattR]

probably hard to tell as the car is in the garage, but you can kind of tell the axle is pushed back.

 

[MattR]

Did you install relocation brackets to move the pivot point on the axle lower? That's a must on a lowered vehicle to improve the instant center for better traction.

Yes I do have them, set in the middle hole.

 

[Tight Lines]

Use the lowers to set thrust but also set them to 107" hub to hub wheelbase. Then adjust pinion angle. I am only assuming, but I would bet you are pass 107".

 

[SCGallo2]

You should be hooking much better with 315 Nittos and are probably losing grip due to extended wheelbase as your car sits now. Adjust the LCAs to stock length and start from there to adjust thrust angle as needed. Then adjust the UCA as needed to achieve -2 degrees pinion angle. This is an easy job in your garage on race ramps or jack stands, just make sure the car is level and suspension is loaded. I have seen good shops with little experience with our chassis screw this up before.

 

[MattR]

Thanks.

 

[MADRUSSIAN]

I got a 29.5 qtp tire....had to move my axle about half inch forward, because tire rubbed on pass side mud flaps pretty bad when car squats.

 

[MattR]

Pass side is where I can only get a pinky finger between the tire and flap.