funny, all this fuss about ducting & thermostats and few people do whats important:

1) maintain their coolant system (dump old for new)
2) bleed their system properly
3) run an ACCURATE water temp gauge

i removed the lower tray, run stock radiator and have vdo gauges for oil, water, etc... temps were always good (~180-190) and on super hot days out here in socal.. ac on, off, uphill runs.. all the same.

as for running with no thermostat, well.. if you generate that much heat you're better off just getting a lower temp thermostat.

Myth.

Indeed. The fans are going to turn no matter what. If the force of the incoming air is all there is to turn them, then they will effectively offer resistance against it. If you give 'em a little electric oomph, they will help it along.

I thought the consensus was this ISN'T a myth.

Heck, the newest MS-iii firmware is going to add a trigger to prevent fans from running at WOT.

IIRC,

In WWII airplanes, it was discovered that propeller aircraft, when in an engine failure or engine off condition, actually required a much steeper glide path, when the propeller was spinning vs. a more shallow glide path when the propeller was halted. A halted propeller offered much less wind resistance than a free flowing propeller, and it allowed the aircraft to better maintain airspeed and kinetic/potential energy. In order to counteract this, some later aircraft engines were designed to stop the propeller from spinning in an engine failure/engine off mode.

Until the speed of the fans approach the speed of the air passing through them, the actual effect is more wind resistant than aerodynamic. At full on, the fans are pushing what? 25 mph? 35? How does that compare to track speeds?

Just sayin...

quote from fogger 03: If you've raised the back of your hood (cowl induction?) then put it back down. Mazda put the rubber in there where your hood seals to the rear of your engine bay for a reason. That's a high pressure area and will serve to significantly reduce airflow through your heat exchangers.

now i've stated this before, and i don't know if it's because of my setup (cutout frt. bumper, splitter,etc....) but on MY car, the raised rear of hood allowed alot of heat to escape! yes, in the very center of the hood the air flowed in, but on each side there was hot air coming out at speed as you can see in the video below. and in traffic, when the fans are on there is incredible amounts of heat coming out all across the hood.
lastly, a magazine tested this concept with air and coolant temp sensors all over the place and in fact used a miata as the test vehicle, and there were significant drops in under hood and coolant temps.
personally, i don't like how it looks, but it worked great until i was able to install a drop vent/headlight delete hood recently.

http://www.youtube.com/watch?v=ejPk2eBnr7o

I've done the same and my strings got sucked in after 40mph:




that magazine test was bogus, there were so many flaws in the test method. and i keep asking: why does it matter if your IM's surface temps are 190*F vs 200*f?

like i said, my car might be different with the splitter and big cutout in the bumper. but i did notice that it looks like you just pulled the rubber seal and didn't lift the hood at all, so that might make your results different also. i also noticed smoke coming out from my hood once at the track. i was doing over 100mph and had a oil leak from my catch can make a smoke stream that went up and over the corner of the car.

:laugh: What turbo are you running?

wawaweewa!

Agreed. When I manually activate my fans on the highway the coolant temp drops.

Reality > theory

C

pick a car

point being, you're better off looking at your losses than doing useless stuff like thermostat removal or reroute to cool your motor. sealing off the radiator, larger radiator, maintenance & proper bleeding would be more advantageous. if you're still running into high coolant temps, then get a fuckin setrab oil cooler and be done with it.

i cant understand how anyone judges temps with stock gauges. theyre practically useless (moreso on the nb)

The one that you removed the undertray on, and are running the stock intercooler. You know - The car WITHOUT A TURBO.

Sorry, coolant reroute is proven. Please try again. An oil cooler for my coolant? You do realize the the specific heat of water will absolutely blow oil away every day of the week for the purposes of cooling, right?

Stock gauges are far from useless. Granted, we're not going to tell exactly what temperature the engine is operating at, but a person can tell the difference between 11 o'clock and 1 o'clock

run an oil cooler and tell me what happens to your high water temps


undertrays are overrated. in case you didnt realize, the factory calls them splash guards. they dont tend to do much of anything

The tray keeps high pressure turbulent air from reducing radiator flow. My tray goes back to the steering rack for a reason.

you should never remove a t stat by the way, it will actually increase engine temp... the t stat is designed as a restriction to water flow on the radiator, without it the water will flow too fast thru the rad and will not let it cool down

I don't think that is true. Yes the radiator inlet/outlet delta would be less if you flow faster, but the faster you flow water through the engine & radiator, the more heat you will extract from the engine.
The goal is more engine heat extraction and a cooler engine and not delta between the radiator inlet and outlet.

People who remove a t-stat usually see cooler operating temperatures leading to the motor running in 'warm-up mode' making the car run rich longer.

Wow, really? Do you realize that by using your concept, I can throw money into a fire to become rich!?!?!? STFU, and learn to think logical thoughts - thermostats were designed to INCREASE engine temperatures. That is their primary purpose in life.

It's not possible to extract 'more' heat from an engine by changing the cooling system unless the change in the cooling system fundamentally increases the heat energy generated. Does your theoretical thermostatless setup produce more heat energy than an identical thermostatted setup? Two otherwise identical engine setups that run at different operating temperatures will produce identical quantities of heat energy. The cooling systems will extract identical quantities of heat energy. The setup that keeps the engine cooler is simply able to extract that same amount of heat energy with a lower delta relative ambient air temperature.

Just to chime in here - past weeknd I flogged my car at Road Atlanata in 97F ambient temps in 20min sessions. NEVER saw the temp gauge rise past halfway (yeah, stock temp gauge) and ran long enough to get 184.5F tunnel temps by my foot - was not comfortable. I run a 180 thermostat with 4 1/4 holes drills in the top of it, with a reroute, ebay Godspeed rad, 25row oil cooler... and mad ducting. I also added a splitter this weekend that goes to the rack.

Also, I've heard the same thing with running w/out a thermostat - coolant passing too quickly to absorb max heat. Don't know if it's true for our engines, but in the refrigeration world I work in it's true, too much refrigerant flow will not allow enough time for heat transfer...