Don't worry you aren't. In fact what is stopping me is probably the same thing stopping anyone else from doing it lol...
7MGTE fan clutch
- Thread starter aloshan
- Start date
Well, here's a plot from a Lytron oil to air heat exchanger ES-0714. Nothing special about this one, except it had more flow rates plotted than some of the others. You can see that heat flow measured in terms of dQ/dT gets better with increasing flow rates for both the air and the liquid, but efficiency is dropping as the liquid flow rate increases. Note that for lower liquid flow rates dQ/dT is limited by the thermal transport capacity of the liquid, rather than efficiency as the air flow increases.
In my mind, the important point is that we don't see dQ/dT peaking with flow rate, which we would expect if there is some flow rate where cooling ability peaks and then starts to decrease.
In my mind, the important point is that we don't see dQ/dT peaking with flow rate, which we would expect if there is some flow rate where cooling ability peaks and then starts to decrease.
What is wrong with this statement?
"Cooling air becomes heated as it passes through the radiator. It enters the radiator at ambient temperature and exits the radiator at some increased temperature. It is the difference between the average core, or coolant temperature and the average of these two cooling air temperatures that creates the ability of the radiator to transfer heat to the air. The slower the air passes through the radiator, the higher will be its exit temperature and the higher will be the average cooling air temperature. The higher the average cooling air temperature, the less heat will be transferred from the coolant to the air. On the contrary, the faster the air flows through the core, the less it will increase in temperature on its way through, making the exit temperature and the average cooling air temperature lower. This increases the differential between the average core temperature and the average air temperature, increasing the heat transfer. Increasing airflow by speeding up the fan, by providing an improved fan, by providing or improving the fan shroud, by reducing air restrictions in the grille or engine compartment, or by providing recirculation shields to prevent air from bypassing the core, will all improve heat transfer and cooling."
This is essentially what I would think would be the case. If too much airflow will actually reduce heat transfer, what is it in the above statement that is incorrect?
"Cooling air becomes heated as it passes through the radiator. It enters the radiator at ambient temperature and exits the radiator at some increased temperature. It is the difference between the average core, or coolant temperature and the average of these two cooling air temperatures that creates the ability of the radiator to transfer heat to the air. The slower the air passes through the radiator, the higher will be its exit temperature and the higher will be the average cooling air temperature. The higher the average cooling air temperature, the less heat will be transferred from the coolant to the air. On the contrary, the faster the air flows through the core, the less it will increase in temperature on its way through, making the exit temperature and the average cooling air temperature lower. This increases the differential between the average core temperature and the average air temperature, increasing the heat transfer. Increasing airflow by speeding up the fan, by providing an improved fan, by providing or improving the fan shroud, by reducing air restrictions in the grille or engine compartment, or by providing recirculation shields to prevent air from bypassing the core, will all improve heat transfer and cooling."
This is essentially what I would think would be the case. If too much airflow will actually reduce heat transfer, what is it in the above statement that is incorrect?
T3rril79;1823407 said:
I do. What fan speed would you like it for?
And are we still arguing this stuff? Appears to be a case of too much geek theory and not enough practical experience...
Not so much an argument. I understand that things can be different in theory and in practice, but in the end I would still like to know the reason why.
I hear ya and it's a good thing. Always had a lot of that in myself. Sometimes things can be over-thought however. What you really need is to talk to someone who engineers heat exchangers for a living. Btw in a liquid to liquid exchanger which do you think is the better method, flow or counterflow?
From what I gathered from the wall of text, it seems to not account for volume. If you can't get much heat out because of the flow speed through the heat exchanger, you can get more heat out by increasing how much air gets through it. Hence, high speed fans work well in our case. May not get much heat pulled out in each molecule, but you're getting a lot of molecules moved.CyFi6;1874447 said:
I know a lil time has past on this thread but how do you know that your clutch fan is going bad? is there anyway to check it. I've purchased a new one since the one on my car his never been changed i don't have any overheating issues but better safe than sorry right should i just install the new one and call it a day or is there anyway to cheak if its going bad?
only comment I can make on this is my very first upgrade was a Koyo rad after I felt the heat in the engine bay on my first drive. Never regretted doing that.. lol.
al lewis;1891923 said:
The way that I found was by listening to the car when you crank it up. The clutch will engage for about 5-10 sec (you should hear the difference in sound when it disengages). The other way is by spinning the fan blade (while car is off). If the blade spins freely its bad. There should be a noticeable "brake" when you try and spin it.
The clutch is thermostatic. It engages or disengages based on temperature. I've never seen any behavior to indicate otherwise. If I were to go out and dig my car out from under the snow, I would expect the fan to move pretty smoothly, seeing as how it's really cold, and there is no need for the fan to pull much air at all. There is no "engage" or "disengage" -- it's a variable amount based on the temperature of the clutch. The clutch doesn't know, or care if the engine is running, idle, or WOT. (Though while not spinning, some of the oil will go to the engagement section, this doesn't make much difference, since it needs to be spinning in order to actually DO anything.) There is a bi-metal coil (How it knows what temperature things are) which controls a valve for a silicone based oil. When cold, that valve is closed, and the fan spins more easily.satx88supra;1891939 said:
Test moving the fan while the car is cold, and engine off. They try it again when it's warmed up. It should have more resistance when the fan clutch is warm.
Prevent the fan from moving at all, and start the car. While cold, there will not be MUCH force against the fan blade. Let it go, then take the car out until it warms up. Get it nice and warm, then shut off the engine, prevent the fan blade from moving, and start again. There will be a noticeable increase in the amount of force against the blade.
If there is enough force against the blade at either attempt to cause the fan blade to bend, or it isn't possible to prevent it from moving, (Do NOT use your fingers for this, btw) then your fan clutch is trash.
If there is still very little force against the fan blade when it's hot, or there is no noticeable difference in force, then your fan clutch is also trash.
Crack me up. How 'bout testing it the way professionals do? How 'bout using the greatest source of information the world has ever known to find that method? It's more than a global pornography network you know...
