There may be a more effective mechanical fan available.
09-28-2005, 09:29 AM
#21
That's just what I've always used. It may be even slower...
the only point of the fans is to draw air over the rads when there is not enough air flow generated by the vehicle moving. Whether it's 10mph, or 40, it's certainly not more than 40 that you get ANY benefit from the fans.
It surely depends on the car though.
It surely depends on the car though.
09-28-2005, 09:49 AM
#22
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okay...
if I'm reving the engine at 6krpm at WOT it generates more heat than it does at 3k at 1/4 throttle. The fan is also turning twice as fast which would mean it might be pulling a lot more air through the radiator.
I guess the differential between air pressure in front of the radiator and behind the radiator would really determine at what speed the fan is a helper. At 80mph and 3500rpm, its not doing a whole lot for me... but at 45mph and redline it might be doing some good for me.
I guess we will have to test this a bit to be certain about effectiveness of any additional fan implementation.
I guess the differential between air pressure in front of the radiator and behind the radiator would really determine at what speed the fan is a helper. At 80mph and 3500rpm, its not doing a whole lot for me... but at 45mph and redline it might be doing some good for me.
I guess we will have to test this a bit to be certain about effectiveness of any additional fan implementation.
09-28-2005, 09:54 AM
#23
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Your engine speed logic is wrong...
The fan has a vicious clutch that is heat sensitive. The more heat in the fan clutch the more it releases allowing the pully to spin more than the fan. Sustained engine speed creates resistance in the clutch from the drag on the fan which in turn makes heat. So your fan is likely to pull more air at 3K RPM than at 6K. This is another reason why the fans are useless at any speed.
09-28-2005, 10:03 AM
#24
not to mention, at a given point, the air coming through the radiator will be WAY more than the fan
can possibly move, at which point, the air will actually drive the fan, not the other way around.
09-28-2005, 10:04 AM
#25
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interesting.... however the goop in the coupling should increase in viscosity with heat
which increases the resistance and thus to a certain point should flow more air as the fan if the coupling is at the right temp will be engauged more.
09-28-2005, 10:14 AM
#26
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Works the opposite.
The more heat (and this heat in the clutch is caused by the turning resistance, not engine heat) the less resistance there is. At engine speed, there is no use of the fan, since the car should be moving and flowing air through the front. So this is done to reduce the drag of the fan on the engine.
09-28-2005, 10:20 AM
#28
The more heat you have, the more the liquid binds up...
The thing is, like I said, teh more air that flows through the radiator, the more it cools the VC... the slower the fan wants to turn. You could probably experiment in your garage with an air hose.
09-28-2005, 10:42 AM
#29
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Yeah I'd imagine I would want to keep the coupling as hot as possible
However beign that it is sucking in hot air that has just been through the radiator and the condenser... I'd imagnie the air is quite warm... plus its in a hot engine bay. When I track I have the car out for 30 mins at a time... thats enough to build up a lot of heat in the engine bay.
