[TR] Electric Fan Controller

[Brian Jones]

I have removed the mechanical fan on my TR4 and installed a 16" puller fan.
This exercise was to eliminate the rotating mass of the fan and fan
extension (more than 6 lbs); my car is not prone to over-heating.

I had been looking at the many options for controlling a fan and decided on
this flexible speed controller, bought from Summit Racing:

http://www.summitracing.com/parts/FLX-31165/

This version senses ooolant temperature via a probe pushed into the radiator
fins near the radiator inlet. They have an option that provides an NPT
sender for mounting in, perhaps, the coolant return pipe.

I am very pleased with the quality of this controller - I just hope it
proves durable. The main feature that appealed to me was that when the fan
comes 'On' at the temperature you have set for the controller, the fan
starts at only 60% of its capacity. If that fan speed is insufficient to
bring the water temperature down, over the rising 10 degrees beyond your
temperature setting, the controller gradually accelerates the fan up to 100%
capacity for maximum air movement through the radiator.

This gradual introduction of power to the fan minimises strain on the
charging system of my TR4.

I have mounted the 2"x5"x0.5" controller beneath the near-side horn, so it
is unobtrusive. I took battery-power from the solenoid (the controller
incorporates the relay), and switched power from the fuse box. A switch may
also be mounted in the cabin to either switch the fan on (hot traffic) or
off (Autocross runs). The same switch may perform either function by moving
the switch's wire between either of two push-on connectors.

One more feature - an additional wire connection can be installed to trip
the fan to come on as an air conditioning system comes on, in anticipation
of need.

Anyway, I just thought I'd share in case anybody is considering an electric
fan installation.

Brian Jones
Valley Forge, PA