Howard Jones
Supporter
I have had a ongoing vibration in the front of my SLC. I am beginning to believe that it is related to changing brake pad materials. More on that as I get into this but does anyone has any experience with this. Especially those of you with track experience?
My symptoms:
1. Car feels completely normal at low speeds around paddock, in the street in front of my house, and at very low brake effort stops.
2. On track, on warm-up lap none to very minor vibration in the steering wheel . I will rate it in severity at 1-2 on a scale of ten. Car is being driven at speeds that will heat tires up, primarily moderate corner speeds, engine revs held to 75% and brake effort held to less than 50%.
3. As lap times come down in subsequent laps, full power, hard cornering, and working up to max rate stops, vibration get worse until it is at 8-10 of scale. This is hard to describe but I have looked on the incar video and you can see it in the steering wheel/ hand contact just a bit. I feels much worse that it looks.
4. At no time is it felt in the brake peddle, No pulsation as would be present with a warped disk. Peddle is hard.
5, Disk run out = < .004 all four. Hub rubout = near 0 or < .001.
6. No other indicators in suspension. All rod ends on A arms are ok (took them off car and gave them the what for) , Wheel bearings are good (checked). Calipers are OK in that all the pistons (all four calipers) are free and retract normally when pressed back into the caliper by hand (all feel the same).
7. Steering tight and there is no pulling to one side. Car stops straight at all brake efforts.
More info:
Current configuration: Wilwood 6 piston calipers F Wilwood 4 piston calipers R. Wilwood two piece rotors all around (aluminum hats/ iron HD48 1.25/ 13.06 fronts and 1.24/12.88 R. Masters are both .625 on a Tiltion peddle box.
Car was first built with BP10 pads as a place holder to get the car going and see where I was with brake balance. Changed to Wilwood A pads on front and Wilwood B pads on the rear. The friction value of the A pad is nearly double that of the BP10 and the B pad is nearly so. I think that this issue may have come up at near the same time as the pad change.
Is this a compound interaction problem?
Info I found on Brake Judder:
Any good info you may have would be greatly appreciated especially track related in nature. Thanks in advance.
My symptoms:
1. Car feels completely normal at low speeds around paddock, in the street in front of my house, and at very low brake effort stops.
2. On track, on warm-up lap none to very minor vibration in the steering wheel . I will rate it in severity at 1-2 on a scale of ten. Car is being driven at speeds that will heat tires up, primarily moderate corner speeds, engine revs held to 75% and brake effort held to less than 50%.
3. As lap times come down in subsequent laps, full power, hard cornering, and working up to max rate stops, vibration get worse until it is at 8-10 of scale. This is hard to describe but I have looked on the incar video and you can see it in the steering wheel/ hand contact just a bit. I feels much worse that it looks.
4. At no time is it felt in the brake peddle, No pulsation as would be present with a warped disk. Peddle is hard.
5, Disk run out = < .004 all four. Hub rubout = near 0 or < .001.
6. No other indicators in suspension. All rod ends on A arms are ok (took them off car and gave them the what for) , Wheel bearings are good (checked). Calipers are OK in that all the pistons (all four calipers) are free and retract normally when pressed back into the caliper by hand (all feel the same).
7. Steering tight and there is no pulling to one side. Car stops straight at all brake efforts.
More info:
Current configuration: Wilwood 6 piston calipers F Wilwood 4 piston calipers R. Wilwood two piece rotors all around (aluminum hats/ iron HD48 1.25/ 13.06 fronts and 1.24/12.88 R. Masters are both .625 on a Tiltion peddle box.
Car was first built with BP10 pads as a place holder to get the car going and see where I was with brake balance. Changed to Wilwood A pads on front and Wilwood B pads on the rear. The friction value of the A pad is nearly double that of the BP10 and the B pad is nearly so. I think that this issue may have come up at near the same time as the pad change.
Is this a compound interaction problem?
Info I found on Brake Judder:
Any good info you may have would be greatly appreciated especially track related in nature. Thanks in advance.