My last post was edited since you last posted. Some helpful info in it.

Drilling to half the diameter of the heater hose will effectively work as if no thermostat was present, and your coolant temps will drop rapidly as soon as you start moving.

Actually I see it now and your rite. Getting the hole size correct would be imposible especially with changing revs. This is part of a full reroute and I already have a rad. Thanks for clearing that up. Very helpfull.

Message repeats:

http://ecx.images-amazon.com/images/...KL._SS400_.jpg

Joe, I'm a little fuzzy on this, could you clear it up for me? I don't understand how it shuts off the heater core path when hot. I've searched different retailer's websites, and none of them actually give an explaination.

Let us not forget that the water pump is a centrifugal unit which will flow less water when the flow is restricted. It will not blow open seals or lines and will only flow through the little tiny "jigglered" hole in the OEM thermostat unless a larger hole is drilled.

A 3/16 hole in the thermostat mounted in the rear will allow some critical flow during warm-up to keep the engine from developing hot spots and allow the thermostat to see the actual temperature coming from the engine. No flow through that thermostat will cause too much heat to build in the rear of the engine before it opens.

Blocking the flow completely to the heater(or a clogged heater) in the non-rerouted engine will cause severe heating in the rear of the engine at all times.

is a 3/16 hole a tried and tested method?

yes

Use the OEM two stage thermostat and leave the little "jigglered" hole alone.

then a 3/16th hole it is... or 5mm lol

You can't just dump the thermostat - you have to have some restriction there. The water pump isn't positive displacement - the system relies on temperature differentials to pull water through the motor/radiator.

I have a gutted thermostat installed in the back. No heater core, no heater core lines, no coolant line except the ones for the turbo and the big one to the radiator. The car takes a little while to warm up, and on very cold days it will run ~150*F on track, but otherwise it functions as normal.

Hey Sav this may be off topic, but does E-85 function better with cooler or hotter water temps or overall engine temps?

My heater is currently by-passed, as part of the re-route install on my dedicated track car.

Having spent a day in the pouring rain, with a completely fogged windshield, I now plan on putting the heater core back into the loop!

No idea. E85 should make the engine run cooler. As a rule of thumb, it's more efficient/powerful to run a motor as hot as you can (assuming your ECU doesn't pull timing), but I try and keep the track car as close to 180 as I can to promote motor health.

anyone else have fogging problems? i have bought some anti fog stuff for the windscreen and polycarb side windows.