What sort of gains, if any, could be expected in changing from the standard A12 clutch fan to a 10" thermo on a modified A12 motor?
Cheers Matty

.0000000000002 hp:P nah seriously as useful as it is your using electricity for you fan that has to be drawn from the alternator which is putting load on the motor. When it's off (yay for big triple pass radiators!) you'll get the full potential, it's still not going to be a large number though.

I first tried this setup with my A15 radiator on my A12 and I find I rarely need to turn it on, only in summer and when I'm stuck behind common folk in crawling traffic, mainly the slow moving traffic one. I did notice the engine was more responsive too due to the lack of parasitic drag of the standard fan. On the A14 pretty much the same deal, I'll know more by summer.

As for performance I keep the fan on for all motorkhanas and sprints and it does well enough to keep the temp stable. I run a 12" fan though Matty

Cheers mate
I am yet to measure the radiator width but if a 12", or even 14", fan will fit I would go with the bigger option.
Interesting that you did notice a difference in changing from the clutch fan.
Thanks for letting me know.
Matty

Quote:
Do you mean the B310 clutch fan used with Air Conditioning? The standard fan is a fixed fan, and has no clutch


...to a 10" thermo

The B310 clutch fan is thermo controlled. It spins more freely when cold and less free when hot. It is 350 mm diameter - steel, 7 blades.

Nissan thought it is was important enough to use instead of the standard fan. My guess would be as much as 5 HP at 6000 RPM for this fan if not using a clutch.

The standard 310 mm diameter plastic fan takes what? 1 or 2 hp?

For the best savings, use an electric fan like that used on N10 or B310 models. That can save 100% of the fan power when the fan is switched off. It only runs when the engine needs it. Electric fan: 320 mm diameter, steel 5-blade (some 1980-1982 B310s)

Thanks DD I do mean the fixed A12 fan.

I just bought a 10" electric fan with a rating of 1550 CFM.

I dont know if i will use it or use the original one.

Has anyone ever built a fan shroud for the stock fan to get it to be a bit more efficient? Thinking of fabbing one up at work and bolting it on with my new rad.

I have a stock Datsun 1200 fan shroud. It doesn't seem to make any noticeable difference.

im a big fan of the thermo

noticable power diffrence between mechanical fan and switched off thermo fan

they are hardly ever required to run if you have a well maintained cooling system

definately go thermo

especially when you consider bang for buck, $50 for 5 HP, thats as cheap as it gets!!!!

people spend thousands getting compnents lightened and balanced to reduce windage in the sump and inertia of the drivetrain.... having a fan hanging off the front of your motor is pretty much a mortal sin considering this

standard A-series fans 310 mm



factory clutch fan thermostatically controlled



factory electric fan from Pulsar N11

My guess would be 1-2 HP but when I go back to the Dyno if time permits I'll pull off the standard plastic fan.....it takes me all of a minute to do..................would be interesting to see what the difference in horsepower.

Tom