Originally Posted by Joe Perez

18psi more clearly stated a point that I was trying to imply.

The turbo is always spinning. It spins at idle, it spins at cruise, it spins at WOT. Depending on the size of the turbo, the design of the exhaust system, and quite a lot of other variables, it's even possible that it may be spinning fast enough at high-speed cruise to make some amount of "boost" between the compressor and the partially closed throttle plate.

But none of this should be causing overheating. I have driven my turbo car (which, incidentally, is missing most of the front shrouding) from San Diego, California to Phoenix, Arizona and back, twice, both times in the summer. You may not be familiar with the geography of the western US, but this is a roughly 600 km trip that goes across some mountains which are over 1.5km in height, and through a desert in which the temperatures in the summertime are commonly 40-45°C.


So, if you are overheating, something is wrong. Maybe there's a pressure leak in the cooling system, maybe your thermostat is crap, maybe there's a blockage somewhere...

A good start would be a coolant reroute, which fixes a major shortcoming in the design of the Miata cooling system, restoring it to the way it was when this engine was originally installed in FWD cars, specifically, removing the thermostat and moving it to the back of the head and blocking off the port on the front of the head. There are a couple of commercially-available kits to help you do this, if you don't want to assemble it yourself:

http://www.etdracing.com/m-tuned/pro...products_id=85

http://www.bellengineering.net/produ...roducts_id=300

Big, aluminum radiators are also very pretty, and some folks believe that they improve cooling performance as well.



The turbo melted the aircon comopressor? I don't even know what this means. But you could always put a heat shield between the two.



Nearly a worst-case scenario. With the top down, the aerodynamics of the car go completely to ****. The engine has to produce far more power to propel the vehicle through the air at 140km/hr with the top down than it would have to make do to the same with the top and windows up while also powering the aircon. It should still be able to do this without overheating, just pointing out that you may be unknowingly aggravating whatever problem exists.

Originally Posted by cueball1

I used a sheet of 1/4" thick ABS. Anything fairly rigid and won't be effected by boiling point temperatures would be fine.

Originally Posted by faeflora

Eerrrghhh these track ****** (savington and hustler) are recommending solutions for racing, NOT for what is essentially just daily driving, albeit high speed driving. You don't need ducting for day to day driving. It might fix your problem but I think that first you should swap out your thermostat. It is much less effort and is likely the real problem.

I also think you don't need a reroute and you don't need a big aluminum radiator.

I think your problem is most likely just your thermostat.

Originally Posted by miatasc

Try replacing your coolant with pure water + Redline Water Wetter, put the fans working in parallel, a lower temperature thermostat, a 1.3 bar Cap...
A bigger aluminum radiator as a Koyo or PWR will help too as well as the re-routing.

Good luck.
Ben.