I think you where right about my coolant problems, the headgasket is not blown but the hose that goes to the heater pumps was not blocked off tightly enough.
Glad it was this and not the headgasket. It's really amazing how much pressure you can build in the system with normal use and how it will find the little leaks.

Anyway I have some more questions for you. The first is brake ducts again. It seems the ducts direct air into the wheel arch, but not that close to the rotor or caliper. How effective are they?
You are correct as to how it ducts the air. It directs air to the caliper and not like a full racing setup to the rotor hat.

I can tell you that I have been completely satisfied with the ducts. REALLY terrific and I have zero desire to proceed with a more racelike setup. Just hasn't been required at all.

When turning right, I assume the left duct is ineffective becasue the tyre blocks air flow. same I guess on the right duct turning left.
I wouldn't think of them working this way. You are either putting heat into the brakes (braking zones) or removing heat (in a turn, on a straight). The ducts accelerate the heat removal process by routing air to the system, right? Anytime you are not on the brakes, the are helping you; I really don't think there's any relationship to straight vs. turns and the effectiveness. (Note that early track drivers tend to spend too much time on the brakes by braking both early and too lightly - this increases the brake heat by reducing the heat removal time; be sure you have good technique to maximize your heat removal time)

I suppose in very hard turns you might loose some flow however that's a very very small percentage of the time that it's never been significant for my setup.

After my first ten minute spin, by brakes where smoking at the front. temps where 90+ degrees, I was pushing the car pretty hard, but I didn't think it was that hard. anyway, my question is really with custom brake ducts that I will eventually make, is it enough to just having the air going into the wheel arch, or just I create a tube to go right to the rotors and remove the shielding for the rotor on the strut?
Yes - the stock brakes don't cut it on the track. I can only advise that I have ZERO brake problems with my current setup. M5 front brakes, stainless lines, 540 ducts, stock rotor guards in place and PBR metal master pads. The brakes are predictable and have no fade over 25 minute sessions. Do the brakes get hot during the session - hell yes. Do they fade or go away. Nope. And we have some HUGE braking transitions in our local tracks so I don't think that you're track can be any worse.

Cheers!

Jeff