Project: 1995 Miata

[Jake]

at track speeds in open air, even an original miata cooling system should keep the car nice and cool.
Going 70/30/WW may band aid the problem but it sounds to me like there is something else going on.

Thermostat is cheap to replace but they are designed to fail open, i doubt thats it. (and if it failed closed it would have pegged the temp)

Was the engine detonating at all? Rocks in a can?

can you check/set timing on the 99 engine?

Hrmm. That was my thought too. My old motor never ran hot like this.

Engine did not sound weird at all, just didn't make as much power.

I'm using the 95's Cam Angle Sensor - someone said the 99 motor should set timing automatically (versus the NA's motors where you can advance it manually) but I don't know for certain.