Electric fan

[Propshaft]

I have kicking about in my garage a 12inch electric fan would this be big enough for my stag if I ever need to use it

[StagJonno]

My instinct is that it will be too small if you're looking to replace the standard viscous-coupled fan, based on the Kenlowe information I had at the time I bought the fan for my car. They had an uprated 14" fan specifically for the Stag Extracts from Kenlowe Web Site - Stag.pdf.

As you can see, the 14" unit they recommended for the Stag was the highest electrical rating in this range of Exteme High Performance Fans. Having said, this fan has 2 speeds, with the High speed pulling 24 Amps. I use this electric fan only (having removed the standard viscous-coupled fan) and found that the Low speed is adequate in all conditions I've experienced (when controlled by the Davies Craig electric water pump with their controller), which pulls 18 Amps.

Kenlowe used to set the benchmark for aftermarket automotive fans as well as OEM for many moderns. Around 2016/ 17 they withdrew from the aftermarket business to concentrate on OEMs.

If you want to just add an electric fan to supplement the viscous-coupled fan, the one you have may be adequate. Hopefully others with experience of this configuration will contribute their experiences. It's worth noting that any additional fan will partially obstruct the airflow through the rad when it's not running, so higher temperatures may be experienced from a fan that's not capable of shifting the required amount of cooling air.

[Propshaft]

Thanks for your informative reply

[wilf]

IMHO, no aftermarket electric fan should be supplied via the original wiring/ fuses. Supply should be via a relay, with a new fused feed direct from the battery,
Any fan large enough to cool the Stag engine will draw far too much current for the original loom to supply.
Also, as hinted at above, an electric fan should supplement the original viscous- coupled engine driven fan.

[DJT]

It's worth noting that any additional fan will partially obstruct the airflow through the rad when it's not running, so higher temperatures may be experienced from a fan that's not capable of shifting the required amount of cooling air.

When I fitted my 14" 2-speed Kenlowe about 20 years ago, I wanted an indication to let me know when it was running. I added an LED light, tucked beside the dashboard. At speeds above 45mph the LED illuminated, which puzzled me for a while until I realised that, at those speeds, the flow of air through the front grille was enough to rotate the fan backwards, allowing it to generate enough current to light the LED. Fitting a diode in circuit stopped the light coming on unless the fan was actually working. The fact that the fan will freewheel when moving proves, in my mind, that obstruction of air through the radiator is minimal.