We could go through the whole design process or we can start just by looking at the issues. I would enjoy working through this with you. I get a real kick out of this $hit!
Let me ask a couple of questions:
Non-racing temperatures
- are you able to lock all four wheels
- is the amount of pressure required on the peddle to lock all four wheels to your liking
- do the front tires lock first
Now answer the same three questions for the situation you described after 10-15 minutes on the track.
- when the brakes go away, is the peddle still high and hard or does it get spongy
- is your proportioning valve adjustable? if so, who is it made by and where in its range is it set
- please describe in some detail the layout of your ducting.
- have you checked you tire temperatures and if so what do they run after the problem you described. if not, please do so!
- have you noticed any pad taper
Some notes on your pads. The D compound begins to fall off at 600 degrees. That is not very hot. I have used the J compound with a good deal of sucess. Its torque curve is very flat to over 1300 degrees. At that point you rotors will glow red. I don't have my formulas in front of me but it will not take long to reach 600 degrees.
By the way, I have a bedded set of J pads for sale. But before you consider them, lets work through this. Also as a note of interest, the J compound has a higher torque value (CF) cold than the D compound or even the cold stoppers (tan pads). The statement about high temp pads not working when cold is NOT always true.
For all the big wheel, big brake advocates....... the ONLY thing that a larger rotor will do is increase the mechanical torque available. This means that for a given rate of deceleration your peddle effort will be lower. The other thing is IF the mass is greater, the temperature rise will be slower. That is all folks!
Get ahold of True Choice (
www.truechoice.com) and get some temperature paint, pads and use them at the next event. It will provide us with information that would take hours of calculations to even some close to!
Hang in there and we will have you stopping on a dime!
Rick