pad question

[bryant]

do i want to run racing pads only in the front or on all 4 corners?
i have been running racing pads on the front and had street pads in the rear. it would lock the front tires under hard braking.
it has willwood dynalite 4 piston calipers all the way around. the front tires are 255 and rears are 275s.
i have an adjustable portioning valve but its fully backed off allowing max pressure to the rear.
so am i at a good brake bias at this point or would i benefit with more aggressive rear pads?

[Apogee]

Given that you're locking the fronts before the rears with 100% pressure to the rears, you're leaving a little brake performance on the table. If you were to move to a higher CoF rear pad compound, you should then be able to handle higher brake torque at the rear and then use the adjustable proportioning valve so that you still achieve front lockup first.

What pads are you running up front? What are you running in the rear? You don't have to run the same compound in the rear, but it sounds like you can tolerate more rear brake at this point.

Tobin
KORE3

[bryant]

i was running pfc 01 compound pads in the front and the stock wilwood pads provided with their kit in the rear. the bp-10s i believe. i just purchaced some hawk black pads for the front.
any suggestions on a rear pad?
should i run the same pads as in the front?
the rear kit is this one http://www.wilwood.com/BrakeKits/BrakeKitsProdRear.aspx?itemno=140-7140-DR
it has 3 sq in of piston area
the front kit is this one http://www.wilwood.com/BrakeKits/BrakeKitsProdFront.aspx?itemno=140-13476-R&year=1966&make=Ford&model=Mustang&option=Drum+Brake+V-8+Spindle+Only
it has 4.80 sq in of piston area

[nokones]

What are you doing with the car? Grocery getting, autocrossing, track, or combo autocrossing/track?

[Apogee]

Are we to assume this is the Maverick in your signature line? If so, aren't they fairly front heavy in stock form? Something like 60/40? Have you changed your front/rear weight bias much, as that could certainly impact how your car transfers weight. Without additional info, I would probably try running the Hawk HP Plus pads in the rear, or something similar, as they have a comparable temperature rating, slightly lower CoF with similar CoF versus Temp curves, and won't be as hard on the rotors as compared to the Hawk Black compound. You'll still have the adjustable proportioning valve to find the sweet spot, but you'll have significantly more rear brake torque than the Wilwood BP-10's offer.

Tobin
KORE3

[bryant]

What are you doing with the car? Grocery getting, autocrossing, track, or combo autocrossing/track?
autocrossing and weekend cruising.


Are we to assume this is the Maverick in your signature line? If so, aren't they fairly front heavy in stock form? Something like 60/40? Have you changed your front/rear weight bias much, as that could certainly impact how your car transfers weight.

Tobin
KORE3
yes its the maverick
i did have it on 4 corner scales a year ago. i remember it being just over 50% on the front. i have changed the bias significantly from stock. carbon fiber hood, aluminum heads, battery in the trunk, wilwood disk brakes. 8 point cage, 9" rear end, no back seat, lightweight racing front seats, and sound deadener from the rear valance to the firewall. all contributes to moving the weight bias back in the car.

ill try the hp plus pads in the rear. i dont have time to get them for this weekend but ill get them for the next autocross. that will allow me to see the difference.

would it be helpful to put a brake pressure gauge on the rear line to get an idea of how much the rear pressure is being reduced or just try different amounts of adjustment on the knob?
also on adjusting the proportioning valve, wilwood says try 2 turns at a time on adjustment. is that what you guys would recommend?

[Apogee]

When I set up an adjustable proportioning valve, I typically start near the lower pressure range of the valve adjustment...somewhere around 7-8 turns out. All of the way out (CCW), 11-turns, essentially moves the pressure set point to 0 PSI, reducing the rear brake pressure to 57% of the front. All of the way in (CW) essentially takes the valve out of the equation, as it moves the set point outside of the normal operating range for most applications. Then I test it and make full turn adjustments until I find the point where the rears start to lock right around the fronts under a full deceleration stop. Once I find that point, I typically back it off one turn and call it good. While you can certainly do 2-turn adjustments, you may overshoot and then need to backtrack a bit in finer increments.

Tobin
KORE3

[bryant]

ok so i had it backwards. the proportioning valve was all the way out which ment i had the rear brakes cut way back!!!. so i started turning the knob in during runs and got to a point where the rear end seemed to feel a little squirly braking into a turn.

Thank you Tobin for the great advice.