Im running 5 psi but i havent boost til redline yet because of this problem i think the boost creeps up to 10 but ill deal with that problem once i figure out this cooling issue.

:facepalm:
I'm going to now tell you to undo all the stupid shit your "friend" did first, before diagnosing any other problems.

NOT a compression test, a PRESSURE test. Testings the cooling system...

^^ This is your problem, and this is why you are loosing coolant. You have completely taken the radiator bypass out of the coolant system. Your engine coolant stays cold, your thermostat stays closed. At high RPM, your water pump is trying to push A LOT of fluid through the 2mm hole in the thermostat. Your coolant is pressurizing something extreme. (And definitely unsafe for your head gasket) Look for where your friend capped off the heater line. That is where you are losing water. Drain the oil and make sure it's not milky.

Parts:
E301-15-287 O-Ring (For metal pipe to mixing manifold connection)
BPE8-15-290 Pipe, Bypass (Metal Pipe)
NA75-61-211 Hose No.1, Water (Head to heater core)
NA75-61-212 Hose No.2, Water (Heater core to metal pipe)

I'm not sure I've ever seen a Toyota Miata, usually they're Mazdas ;) He doesn't work in throttle pedal design, does he?


Edit: P.S., for posterity: http://en.wikipedia.org/wiki/Tri-state_area

Looks like fooger just won this thread:D

you're right, but a compression test wouldn't hurt either.
(just trying to cover up the fail:D)

Fooger thats what it is the pressure broke the radiator cap i ordered the parts from Mazda they will be here thursday! I appreciate the help dudes, i really hope i didn't blow my head gasket i only drove maybe 10 miles while i was testing it.

How many g's are you boosting?

Well done on ordering parts. I still have a concern though, because your radiator cap shouldn't be under any unusual pressure if I'm correct...If your radiator IS indeed under unusually high pressure, then you have something blocking coolant passage between your lower radiator hose and your water pump. I would suspecting your mixing manifold in this situation. How exactly did your Toyota friend go about capping the mixing manifold when he removed the metal heater core return pipe?

im boosting 5 psi he capped the the hose coming out of the heater core return at the end of the rubber section.Then we put a cap on the coolant inlet tube

After looking at the cooling diagram it is not good im glad i didnt drive it to far.

How about how many gs ($$$) do you have in your boost?

The kit was 1500 i had the ms that was 550 so alittle over 2gs and a act clutch i got second hand for 200.

Cryswht93N/A,

Dude, I can't read your posts. The lack of punctuation is driving me insane. One more thing, when you use I when referring to yourself, it needs to be capitalized.

Pressure testing your radiator with a possible head gasket issue is a good way to hydrolock your engine.

Do a leakdown test with the rad cap off and see if you get any bubbles. No need to go crazy with the psi, regulate your feed down to about 20 psi and go from there.

Or...pull the cap off and start the engine. Watch the radiator opening and rev it up. If you get coolant flowing out like a bitch, you've got a bad headgasket.

On another note, you got your kit already?:fawk:

I received the kit a week ago, the only thing missing was the tap I order. Im happy with it, I had the hose replaced today and the dealership said its fine. It runs good, does NOT overheat anymore. I still have to get it tuned better....

The Mazda dealer is fixing your turbo Miata? Any comments from them?

C