e fan conversion, where to mount swirch

[MarkM66]

Originally Posted By: mk378
It would be really easy to solder another tapping into the bottom tank of a metal radiator. Plastic, not so much.


Yeah, good luck with that. Solder is for wiring. It would need to be brazed.

I always just put mine on a togo switch. But if you're forgetful, that could be a problem.

 

[meep]

If you really want to conserve power, the sender needs to be on the cold side of the radiator. you want the fan kicking on when the radiator is ineffective itself from sitting still or inadequate speed.

Example: you're doing 60 mph. Engine is working and outlet temps are 220. if the sender is on the hot side, the fan is on. BUT, you're doing 60--- and even without the fan, the radiator would be outputting 160. Adding the fan, since yo're doing 60... doesn't help.

But when you slow down, the rad is not effective, and the cold side raises to 170-180-190 now you need it, and the fan kicks on until either it controls the temps, or you're moving again.

e-fan still drags on the alternator. a 25 amp load at 14V is ~340 watts which without losses is ~1/2 horsepower. Assuming the alternator is 33% efficient (I have no idea how efficient they really are), that's 1.5 hp at the pulley.

 

[hansj3]

Originally Posted By: meep
If you really want to conserve power, the sender needs to be on the cold side of the radiator. you want the fan kicking on when the radiator is ineffective itself from sitting still or inadequate speed.

Example: you're doing 60 mph. Engine is working and outlet temps are 220. if the sender is on the hot side, the fan is on. BUT, you're doing 60--- and even without the fan, the radiator would be outputting 160. Adding the fan, since yo're doing 60... doesn't help.

But when you slow down, the rad is not effective, and the cold side raises to 170-180-190 now you need it, and the fan kicks on until either it controls the temps, or you're moving again.

e-fan still drags on the alternator. a 25 amp load at 14V is ~340 watts which without losses is ~1/2 horsepower. Assuming the alternator is 33% efficient (I have no idea how efficient they really are), that's 1.5 hp at the pulley.


True about the power drag being consistant with what a mechanical fan would, it works out to about 3-5 HP on the dyno, e fans can push 50 to 80 amps, but they dont run on the highway, so the gain is where I need it, and the engine pushes the low 100s for a power. Any bit helps

 

[meep]

I would suspect the 50-80 amp being locked rotor current (startup) that decreases immediately, but I've never measured one. Do you know what the actual running currents are?

Does the location discussion above for the temp sender make sense?

 

[Rhymingmechanic]

I think one of the aftermarket fan companies used to make a probe that went into the radiator hose itself, but I didn't find that style in a quick search. Maybe they leaked.

It looks like the ticket now is the hose adapter like linksep posted. Install the sensor and then splice the adapter into the hose of your choice. The return hose does make sense with an adjustable thermostat.

 

[SteveSRT8]

Originally Posted By: 440Magnum
Originally Posted By: BurrWinder

Coldest part of the radiator - not in a good location for the flow of coolant.

BurrWinder


You actually WANT an electric fan sensor to be at the radiator outlet, not the inlet. The engine water outlet temperature is pretty constant, so the fan would be off until the engine actually OVERheats, then it would kick on. You want the fan to maintain a relatively constant temperature water feed INTO the engine, and only come on when natural air-flow isn't adequate. Every fan installation kit I've ever seen recommends either a sensor in the return hose, or as near the return tank as possible when inserted into the radiator fins.


Good post. Folks need to know if they have a reverse flow cooling setup as well.

I'm running an old adjustable Flexalite switch on an e fan conversion that simply tie wraps the probe to the outlet hose on the radiator. Works well for us, the vehicle has a much larger radiator so it needs very little fan.