electric fans (generator?)

I don't think they would contribute very much.

I have read that a foot on the brake pedal when shutting off the ignition will eliminate the run on condition. The extra draw of the brake lights along with the ignition saps the power output of the fans spooling down almost immediately.

If you install the diodes (intended to prevent run-on) the fans will not provide any voltage back to electrics from "windmilling".

Maybe you should apply for a patent for this technique!

Rocky

as for the run on possibility, I did not look at the diode method, but the use of new relays with heavier wiring from ampmeter to fans.

I was initially thinking a "running" fan might restrict air flow if the thermal switch keeps the fans in run all the time, but realized the fans would be driven by air speed anyway

The loss of just around a full volt (8% plus) through the diodes noticeably slows the speed of the fans, best to avoid them if possible.

Improving the fan ground circuit with direct grounds at the fans (rather than the factory daisy chain of grounding ending at the infamous 'stud under the dash') will also noticeably speed up the fans, particularly if headlamps or markers are on too.

Jon Haas's radiator fan controller will solve that problem and more.

http://www.pantera-electronics.com/rfc.htm

. Diodes are a bad idea and perform exactly as Larry stated. I took mine out of the car and applied the brake method UNTIL I discovered John Haas's fan controller like alasorsa.

Looking at the schematic in the link for Jon's fan controller. It's not explained how/why the blue wire to the A/C condenser works.
If you had a forward mounted condenser, I would guess it would run the radiator fans for air draw through the condenser. What does it do for a rear mounted condenser fan? Wouldn't the A/C condenser fan be best controlled by a trinary switch reading high side A/C system pressure?

From page 10 of the instructions.
"5 - GREEN wire, A/C terminal for front mounted condenser, same as the A/C
compressor clutch wire. (does not need to be connected if not needed)"

You only use this terminal if you have a forward mounted condenser. My guess would be that it tells the RFC to turn on the fans for the A/C sytesm if they are not on for the radiator cooling system.

Dave asked me to comment on the RFC.

The diodes that used with the relay's have a voltage drop of 0.7 Volts to 1.0 Volt this lowers the speed of the fans due to the lower voltage.
The RFC also utilizes diodes but used in a different way not to lower the voltage but to return the unused power back to the battery.

In the condition when the A/C condenser is in front of the radiator the air flow should be as high as possible since A/C is a differential heat mover, the evaporator is proportional to temperature of the condenser.

The A/C terminal on the RFC is to force the RFC to drive the radiator fans at maximum speed to cool the front condenser. Since the fans are some distance away from the condenser and the engine radiator acts as a restrictor, the fans are not as efficient as the factory arrangement in addition the heated air from the engine radiator is less dense and does not move as well. (fans are constant volume movers not constant mass flow movers)

The A/C terminal on the RFC should not be used when the condenser is in the factory configuration.

I hope that helps.
I hope to see everybody at POCA this year, the event sounds like a lot of fun.

Thanks Jon,
I wondered about the function of the RFC and A/C fan.

For the foward A/C condensor, will the fans run continious when A/C is on no matter car speed since it appears the RFC senses only radiator outlet temp?

Another question Jon, the photo of the sucker fans looks like a stock radiator except the tube connections have been modified. if there a link or discription?

The thermostat controls the compressor and condenser fan and will cycle on and off based on the setting of the thermostat. The radiator fans will operate at full speed only when the thermostat contacts are closed.
When the thermostat contacts open then the RFC uses the temperature sender in the radiator as a reference in a closed loop operation.

The radiator in the RFC installation manual is a modified factory radiator to PE specs. It has 2 rows of cores that are centered to look like there are 3 rows. The tanks are modified and the factory temp switch holes are removed and a 3/8" NPT port is added for the RFC temp sensor.
The radiators are modified locally for me to sell to customers that want this light weight efficient design.
No link, proprietary design.