Thread: Cooling CFMS

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How much cfm does a mechaical fan produce? Electrics all have ratings but I have never seen a comparison.

A large bore V8 requires about 4,500 CFM.

Electric push fans are only 80 percent as effective as that of a solid or flex fan.

High performance Flex a lite brand dual electric fans will run at:5500CFM in pull configuration.

Steel blade pully fans can run as high as 5400CFM at 2000RPM

We run a 16" SPAL electric fan on all the cars('28-40 Fords) that leave our shop, mounted behind th radiator, with a full shroud on the core.

They will idle run at the thermostat temp all day with the A/C blowing.

My personal '32 has a 11.5:1 compression 327 with 2x4's - runs 180 with the air on.

hmmmmmm, A 40amps worth of electric fans at 12 volts..

40A X 12V = 480Watts

480Watt/750Watts/HP = 0.64HP This is a little more than 1/2 a horsepower of air moving ability....

An engine driven fan can easily hit 5HP even up to 10HP.

This will move a HECK of a lot more air than any 12V electric fan could ever hope to dream of imagining of etc.

Now is this amount of air always required? Of course not! But when I'm on the way to the beach over the "hill" with a car load of stuff and people on a hot day, with the A/C on I fore-shore want to be able to tap that 5 HP if I need to.

The other thing that is not pointed out is... If the engine runs the fan runs... With electrics.. If the fuze blows the fans don't run. If the wiring fails the fans don't run. If the temp switch fails(I've had three fail) the fans don't run. If the relay fails the fans don't run. If the alternator has a problem you aren't going to get very far on total-loss while sucking 40amps.

These are the reasons you don't see electric fans on commercial vehicles. They aren't as reliable.. they can't be.

Interesting point Denny. I think a lot of new cars need e-fans cuz they put the engines in bassackwards can't even stick a fan on the front because its the side ?!?!? The other problem I think is emissions. It's hard to run an engine driven fan while the car's owner is in the grocery store and the engine isn't on. Hahahh.

I guess it's for emissions. They can't let the carbon/gasoline vapor container get too hot or it vents defeating its purpose.

It's those OEM fans that have given me the troubles too!
E-fan, Sacramento, 110F, Freeway, Fan Switch, Fiat. Bad juju... Bruhahah!! (owners manual said, " Do not drive vehicle at speeds over 50MPH for extended periods".)

I hung a brodie in mud with that car on a remote country road with my Buddy and our two gals dressed to the nines for a formal dinner. Two of the tires came off the rims....