Rear Brake Lockup Help, Help Options

[spaceshuttle]

I am running larger 4 piston Outlaw (read Willwood) calipers on the front of my v6 track car, with 911 M calipers on the rear. I installed a brake bias adjuster knob initially but my rears lockup under heavy braking no matter the adjustment. Switched to a Tilton bias adjustment with the notched rod with multiple positions and still no change. I cannot tell that there is much difference in the pressure to the rears. They will lockup no matter the position under heavy braking. They are not sticking. Not sure which direction to go from here. I am running Hawk blues front and rear. Perhaps a less aggressive rear pad? And yes the factory proportioning valve was removed.
thanks for any help guys.
LC

[wndsrfr]

I am running larger 4 piston Outlaw (read Willwood) calipers on the front of my v6 track car, with 911 M calipers on the rear. I installed a brake bias adjuster knob initially but my rears lockup under heavy braking no matter the adjustment. Switched to a Tilton bias adjustment with the notched rod with multiple positions and still no change. I cannot tell that there is much difference in the pressure to the rears. They will lockup no matter the position under heavy braking. They are not sticking. Not sure which direction to go from here. I am running Hawk blues front and rear. Perhaps a less aggressive rear pad? And yes the factory proportioning valve was removed.
thanks for any help guys.
LC

Interesting....I've got a similar setup, Wilwood fronts #120-11131 with 1.62 inch diameter pistons, and 38mm 911 rear calipers. Depending on which Wilwood piston diameter you are using, with 48mm "M" caliper pistons in the rear, I suspect that you may have too small Wilwood piston diameter. It's all in the ratios--I'm using Porterfield R4 compound pads all around and have had no rear lockup issues. The Wilwoods come with several sizes of piston diameters....here's the link to their page:
http://www.wilwood.com/Calipers/CaliperLis...lite%20Internal