my car is overheating, but only when i sit at idle at the traffic lights, i pressume this is because the fan is struggling to pull air through the intercooler and radiator at the same time, when its at low speeds (intercooler being in front of the radiator)

would a electrical fan do a better job at idle? and maybe save me my overheating woes?

yeah get a thermo fan man, get 2 10" or 1 12". from what i have been told (im lookin into buying one also) it will improve idle, fuel econ etc. worth the $200 i recon

gee i wouldnt spend $200, i have some that i got for like $20-30, think i gave away most of the good ones i had though

yeah i was lookin at them yesterday, gotta get one for my rotary. $80 for a crap one, $200+ for a good one :)

The engine fan runs at its slowest when most needed - at idle or in heavy traffic, and runs alot faster when the car is cruising along and doesn't need a fan at all.

The electric fan when switched on will run at max speed when its most needed at idle. And you can switch it off when just cruising along.

So yes, it should help.

do you have a fan shroud on it now? if not, that may be enough to get you by.

i do have a shorud, its probably not the best though

i think ill hook up a thermo fan and see how it goes

4nik8 i was talking second hand you can get fair decent ones pretty cheap if your lucky,

I wonder about replacing the mechanical water pump with an electric water pump. This will greatly increase water flow. Plus now you gain HP.

Quote:
For a drag racer, running an electric water pump drive off a battery that is not charged from an engine driven altenator will release a few extra HP to the flywheel.

For street use, this is not really a proposition as the coolant flow from this system is constant, so it is likely to be too much at idle, & quite possibly too little at full throttle, particularly when pulling up a long steep hill.
If the coolant flow at low speeds is more than you need, then power is being wasted pushing an excess of coolant around at these lower engine speeds.
In a street car, the power to run the pump is supplied from the altenator, which is in turn, driven by the engine. The higher the electrical load, the higher the mechanical load on the engine. If there was any real advantage to using an electric water pump, then i suspect that the car manufacturers would have done it decades ago.

Yeah I agree dodgeman the little A-series water pump has small fans on it which would produce hardly any load. An electric water pump would pull a reasonable amount of load form the battery and in turn an alternator and the effect of hp gain would be negated. I wouldnt want to run an electric pump for the simple reason is that I wouldnt know if it had failed. With the belt driven one I know that if the charge light is on I have probably thrown a belt and hence the water pump is rendered inactive.
An electric pump would be a whole lot of work for little gain.
I still run the factory fan even at 8500rpm!!!.
I dont know how much gain I'd get running a thermo fan as far as HP....but this I know...I was running it all day at wakefield raceway at those revs on a 35 degree day and the water temp didnt get over 80 degrees. I do however have a TF Gemini radiator and a large oil cooler as well from Permacool. it is rated for engines max 250HP ...a little large maybe but the oil temp never got above 60 degrees.

Here's my outlook on electric water pumps.


A mechanical pump varies its flow amount with engine revs, therefore you are not always obtaining the flow that gives the optimal heat transfer time for the radiator vs supplying cooled fluid to the engine components.

i.e. if the flow is too fast it will not give enough time for the radiator to sufficiently transfer heat from the coolant to the air passing through the core fins and therefore higher temp coolant will then flow back to the engine.
If the flow is too slow then it will allow the coolant in the engine to become excessively heated and possibly start localised boiling, probably worse than having the flow too fast. Also, when the engine is below normal operating temp the thermostat closes slightly and therefore causes the water pump to operate against a higher resistance.

So lets say for instance that the optimum flow of coolant from the mech water pump is acheived at 3000rpm, revving to anything above this, in regards to coolant flow, is meaningless and an unnecessary use of power.

Compare this to using an electric water pump with a constant flow rate.
You can keep the water flow at the optimal rate whether you're engine is revving at 800rpm or 8000rpm.

Torque required to operate the alternator to, in turn, provide enough energy to operate the electric pump at the optimal flow will be the same as the torque required to operate the mech pump at the optimal rate, no more, no less. To push 100 litres / minute through a given size hose is going to take 'X' amount of energy, no matter how big the impeller is. General physics states that energy cannot be created nor destroyed, it can however be converted. The mech pump uses mechanical energy to turn the pump impeller directly from the crank, the elec pump uses mechanical energy to turn the alternator which converts the energy into electrical energy to operate the elect pump's motor, which converts the electrical energy back to mechanical to turn the impeller.

Then theres always the extra weight argument, I'd rather bolt an extra 2 or 3 kilos statically to the car than have another 1/2 kilo having to be rotated by the crank. Most people know the theory about rotational masses.

The only other point is that of reliability. Both pumps have bearings that can sieze and seals that can leak. The mechanical pump uses a belt that can break whilst the elec pump uses windings in the motor that can fuse. Either design has its own reliability issues and should be taken into account individually but kept in context to the other. When it all comes down to it, if the temp gauge goes up, pull over.

You can probably guess that I prefer the electric pumps..

This is just from my head, my view, my opinion.

Sorry about the long post.