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Old 08-11-2010, 10:32 AM   #81
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Once the evaporator is covered in ice, warm air is not allowed to pass through. Ice will actually insulate the evaporator. Also, it's a huge waste of money to run a refrigeration system quickly because of the vast amount of power that the compressor consumes. You want to get the most cooling possible out of every cubic inch of refrigeration that goes through the compressor. It is therefore much more economical to run refrigeration slowly, and the cons of frozen evaporators suggest that little to no cooling capacity is to be gained by overclocking the compressor.
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Old 08-11-2010, 03:34 PM   #82
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i removed the thermostat on my 99 mustang with an 03 cobra swap and used it for dd and track never overheated but took awhile to heat up lol
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Old 08-11-2010, 03:48 PM   #83
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Originally Posted by fooger03 :
Quote:
on the track, you don't want your fans turning, they will act to block the airflow at track speeds instead of promote airflow.
I experimented pulling 1 fan relay, then driving on the freeway at 55 mph (it was hot and traffic was a bit heavy). It overheated. I then reconnected the relay, overheating gone.

Bill Cardell observed the same thing driving through mountain passes. Fans help even at speed.
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Old 08-11-2010, 04:42 PM   #84
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Quote:
Originally Posted by JasonC SBB View Post
Originally Posted by fooger03 :

I experimented pulling 1 fan relay, then driving on the freeway at 55 mph (it was hot and traffic was a bit heavy). It overheated. I then reconnected the relay, overheating gone.

Bill Cardell observed the same thing driving through mountain passes. Fans help even at speed.
https://www.miataturbo.net/showpost....7&postcount=23
http://www.jaycorptech.com/pc-62-14-...th-shroud.aspx


You don't count.

edit: or maybe you do. How much of that shroud is 1-way flaps?
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Old 08-11-2010, 06:18 PM   #85
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Originally Posted by fooger03 View Post
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...
This hypothesis is wrong.

In the situation you describe, when the propeller isn't turning, they feather the prop so that the blades are parallel to the oncoming airflow, offering the least resistance. If the propeller cannot be feathered, and it cannot turn, it is an enormous speedbrake.

A spinning fan will offer less resistance than a non-spinning fan (unless it is being actively spun in the opposite direction against the airflow, which is not the situation we are talking about).

It has to. For a given airflow speed, there will be a fan revolution speed which is a net zero impact to that airflow. If the fan spins faster, it will begin to produce thrust and speed up that airflow. If the fan spins slower, it will begin to create progressively more drag the more it slows. Extend this to zero rpm for the fan and you end up with the most drag.

Another way to look at it - a non-spinning fan will create the highest perpendicular delta-v to the airflow. The air has travel across the width of the airfoil. If the fan is spinning, that distance will be less (because the blade is moving out from underneath it as the air is traveling, reducing the distance), therefore less energy will be taken from the airflow (less resistance to the airflow).

Edit: does anyone know if the cooling fans are speed-governed? If they aren't, and there's just a voltage applied across the motor, then they are going to spin much faster at speed than they do with zero incoming airflow.
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Old 08-11-2010, 11:12 PM   #86
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Its five pages long, its late so I will post my universal bullet proof experience:

Coolant as usual, the bigger the radiator the better and the best fans that push the most volume of air.

One thing is I have a switch to turn on the fan on demand.

Stock radiator or aftermarket aluminum no difference, just the largest radiator with the most rows available.

I ran [email protected] with 2 layers of the head gasket removed, 215 compression, NGK 7 and never went past half the temp gauge on hot FL summer weather boosted at 15 psi.
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Old 08-12-2010, 12:36 AM   #87
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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.
Wow, really???? i sure sound like a retard... anyhow, by dyno testing a turbo mustang we've seen increased engine temps when running with no t stat compared to a cooler or even stock t stat installed... so from field experience and also by talking to a former colleague, running with no t stat is not recommended to anybody, if you really think about it the flow restriction is necessary on the cooling system to keep everything working in balance.

i almost forgot, a t stat is designed to achieve optimum engine temp in the fastest time possible, not to increase engine temp
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Old 08-12-2010, 07:22 AM   #88
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Originally Posted by fooger03 View Post
https://www.miataturbo.net/showpost....7&postcount=23
http://www.jaycorptech.com/pc-62-14-...th-shroud.aspx


You don't count.

edit: or maybe you do. How much of that shroud is 1-way flaps?
I think I will replace the fans next with fan relay, and add another small fan infront for the A/C coils.... what so special about this fan?

Sigh I have replaced all the coolant hoses and changed to aluminum radiator, but im still overheating...sad part is my car is not even boosted.... i bet somewhere its leaking coolant

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Old 08-12-2010, 07:30 AM   #89
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Originally Posted by etang789 View Post
I think I will replace the fans next with fan relay,
Sigh I have replaced all the coolant hoses and changed to aluminum radiator, but im still overheating...sad part is my car is not even boosted.... i bet somewhere its leaking coolant
Do you have the Mishimoto radiator? If you have, check the cap. The Mishimoto caps seem to leak very often. My first Mishimoto cap leaked all the time and the second one leaks on the track on a hot day. I just ordered the 22-24 psi cap from FM.
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Old 08-12-2010, 07:43 AM   #90
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And by the way I do not have the T stat. I did a minor change, instead of removing the whole thing and having a big hole for water to go through as I have read some resistance is needed to prevent cavitation.

So the T stat was stripped out on the middle, but the flange is placed on the CH. Only the center part of the T stat is missing, it creates some resistance, not to much flow as when not having anything and not to restrictive when having the whole thing. To me, in my case, in this specific situation, it works for me and is the happy medium.
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Old 08-12-2010, 08:59 AM   #91
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Quote:
Originally Posted by Mobius View Post
This hypothesis is wrong.

In the situation you describe, when the propeller isn't turning, they feather the prop so that the blades are parallel to the oncoming airflow, offering the least resistance. If the propeller cannot be feathered, and it cannot turn, it is an enormous speedbrake.

A spinning fan will offer less resistance than a non-spinning fan (unless it is being actively spun in the opposite direction against the airflow, which is not the situation we are talking about).

It has to. For a given airflow speed, there will be a fan revolution speed which is a net zero impact to that airflow. If the fan spins faster, it will begin to produce thrust and speed up that airflow. If the fan spins slower, it will begin to create progressively more drag the more it slows. Extend this to zero rpm for the fan and you end up with the most drag.

Another way to look at it - a non-spinning fan will create the highest perpendicular delta-v to the airflow. The air has travel across the width of the airfoil. If the fan is spinning, that distance will be less (because the blade is moving out from underneath it as the air is traveling, reducing the distance), therefore less energy will be taken from the airflow (less resistance to the airflow).

Edit: does anyone know if the cooling fans are speed-governed? If they aren't, and there's just a voltage applied across the motor, then they are going to spin much faster at speed than they do with zero incoming airflow.
That is all wasted breath, it's been extensively tested and proven:
http://www.google.com/search?btnG=1&...ling+propeller

The major variable on whether this is true or not tends to be propeller pitch, so in cases where the aircraft has an adjustable pitch propeller, It may be possible to set a very steep propeller pitch to negate the effect; however, on aircraft with fixed propellers, it is very nearly ALWAYS advantageous to have a stationary propeller vs. a freewheeling or "windmilling" propeller.
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Old 08-12-2010, 09:15 AM   #92
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Quote:
Originally Posted by damasodeljr View Post
Wow, really???? i sure sound like a retard... anyhow, by dyno testing a turbo mustang we've seen increased engine temps when running with no t stat compared to a cooler or even stock t stat installed... so from field experience and also by talking to a former colleague, running with no t stat is not recommended to anybody, if you really think about it the flow restriction is necessary on the cooling system to keep everything working in balance.

i almost forgot, a t stat is designed to achieve optimum engine temp in the fastest time possible, not to increase engine temp
In case you've forgotten, we're talking about track driven turbocharged miatas...

Not your dyno queen. The cooling factors going 0mph on a dynamometer are outrageously different from those at 60-140mph on a race track.

If your experience is that running thermostatless increases your engine temperature, then:
A: Stop running antifreeze
B: Add a bottle of water wetter
C: Please post results of your controlled experiment, with multiple and identical runs for each setup in identical conditions.

damasodeljr, don't get your panties in too tight of a bundle. We both agree on the point "Always run a thermostat"

JasonC SBB above has posted an example of an extremely good, absolutely relevant, argument. Had he not been running a shroud, I would have almost immediately dropped my argument. Since he is, I'm not sure.
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Old 08-12-2010, 09:38 AM   #93
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i like turtles.
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Old 08-12-2010, 03:22 PM   #94
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Quote:
Originally Posted by damasodeljr View Post
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
This is true if you consider only a single trip through the radiator. If you consider the entire, closed loop, continuously circulating enigne/cooling system, it is nonsense. In the latter context it violates 2 laws (and 18 more minor regulations, statues, and executive orders) of thermodynamics.

M.
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Old 08-17-2010, 08:43 AM   #95
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I think I can contribute here. I have some experience with power plants. I'm going to oversimplify a little.


On a typical power plant:
The pump to cool the heat source has multiple speeds.
The pump to cool the water/water radiator also has multiple speeds.

When there is large heat production both the heat source pump kicks into high speed and the radiator pump kicks into high speed. It's never only one or the other--water has to move faster through both the heat source and the radiator for it to work.

I suggest that removing the thermostat is akin to kicking the heat source pump into high speed. It can only work if airflow is also increased through the radiator.
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Old 08-17-2010, 09:26 AM   #96
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Guys, you need to stop thinking of removing the thermostat whatever your gauges tell you. Removing the restriction on the engine outlet will reduce fluid pressure inside the block/head. The boiling point of the coolant will be lower leading to vapor pockets which in turn cause hot spots in the head. Just as Hustler pointed out on page 2 and delcbr on page 3... According to the book Four-Stroke Performance tuning by A. Graham Bell the pressure supplied by the pump is 30 to 40 psi at higher revs unless you remove the restriction.

Last edited by j-po; 08-18-2010 at 08:52 AM.
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Old 08-17-2010, 10:11 AM   #97
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Quote:
Originally Posted by r808 View Post
I think I can contribute here. I have some experience with power plants. I'm going to oversimplify a little.


On a typical power plant:
The pump to cool the heat source has multiple speeds.
The pump to cool the water/water radiator also has multiple speeds.

When there is large heat production both the heat source pump kicks into high speed and the radiator pump kicks into high speed. It's never only one or the other--water has to move faster through both the heat source and the radiator for it to work.

I suggest that removing the thermostat is akin to kicking the heat source pump into high speed. It can only work if airflow is also increased through the radiator.
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Perhaps I just don't understand the point that you're trying to make, but here is my counter-argument:

I'm not sure how you get that the water pump can function at different speeds based on how hot the engine is. I'm also not sure where you get two different pumps at. There is a single water pump, which is entirely dependent on engine speed. If we want a pump which pumps faster as the coolant gets hotter, then we need to install an electric water pump. Coolant temps are generally load based, not speed based - If I'm doing 80mph up a 20% grade, my engine loading, and therefore the heat produced, is going to be far greater than if I'm doing 80mph downhill, the other way. In both cases, the water pump is moving at the same speed. We compensate for this with a thermostat. The coolant will get hotter, the thermostat will open farther, the coolant temp in the radiator will increase, the surface temperature of the radiator will increase, and once that happens, the difference between ambient temps and radiator temps increases, which literally translates to a greater cooling effect at a greater load, all while maintaining the same engine speed and fluid 'pump' speed.
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Old 01-05-2012, 01:54 PM   #98
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sup
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Old 01-05-2012, 03:17 PM   #99
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sup
did you fix this ?
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Old 01-05-2012, 03:21 PM   #100
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Well I haven't done any serious driving since 2010 :( I moved and have been deplyed for the last year. Planning on a 1.8 swap soon hopefully. I did go all water/water wetter though which worked for the track day I made this thread for.
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