I tried searching this and didn't come up with anything. Do Miatas not have an after run setting that would dissipate some of the heat from the engine bay? A low setting on the fan to run for a while. Just curious. Not worth the trouble?

 

Not that I know of. MS is powered down when the key is off. With MS3 at least, there is an option to have the fan run while the engine is off, key ON.

 

So how about coming up with a timer. You push a button and it activates the fan relay for an adjustable number of minutes then shuts off. I don't have the electronic skills to fabricate this, but wouldn't this be on the right track?

 

Umm ... why? Serious question. I see no turbo in your sig. Even with a turbo on the vehicle one would want to idle it until temps were stabilized before shutdown. What is it you are trying to avoid?

I have put a switch onto my fans, I can manually activate both of them at any time. But I can't see why I'd need to run them for a bit after the engine is off.

 

My 97 Land Rover Disco would run the fans with key off if it was hot enough.

 

Unfortunately this is not possible on the 01-05. The relays that power the fans have constant power on the 30 and 87 pins, but the 85 pin (high side of the coil) gets 12V from IG2 from the ignition. So to actually trigger the relay, the key must be in the ignition OR you need to install a turbo timer just for IG2.

 

"I see no turbo in your sig." -- It says FM II
Rev -- Does that apply to the 00 cars?
Is power to the fan relay normally off through the ign? If power came from a different route would that bleed back into the system screwing up something else?
Summer time temps can get quite high under the hood without any air moving in the engine bay. After a session at the track, even with a 2 min idle cool down that's not doing the motor any good to set there and cook. I hear noises that sound like the water is boiling out of the center section of the turbo.
If something like this was installed it would be easy enough to use an infrared temp gun on the center section with and without the fan on and see if it makes any difference.

 

Are you engine coolant temps spiking above 200°F when the engine is off?

 

By off I think you mean drive car, let it set for about 5 min, check Tuner Studio to see what the temp sensor reads for heat soak. Then start-idle the car and see what it says.
I'll get those readings later today.

 

yep, that. that's all you should care about when it comes to under the hood temps. if you care about under the hood temps, remove the hood.

 

My old Audi had a small electric water pump to circulate coolant and the fan would operate at low speed until the sensor would shut off at about 140F.

 

OK, so it's about 100 degrees today. Ran some errands came back home, here;s what we have.
Driving around we have coolant(CT) 202-210F depending on traffic Intake air (IA)is 103-107F before setting.
Setting/heat soak:
5 min: (CT) 220F (IA) 115F
10 min: (CT) 217F (IA) 112F
20 min: (CT) 211F (IA) 109F
30 min: (CT) 204F (IA) 109F

Started back up:
(CT) 195F (IA) 113F

Does this sound about right?