That thought crossed my mind too. I briefly touched on it by mentioning going down the highway. I've heard multiple reports of electric fans mounted in front of the radiator actually blocking more air than passing through the radiator when they are turned on at highway speeds (engine cooled down on the highway when the fuse was pulled). But at highway plus speeds, the fan on the clutch can't be taking that much HP with the wind helping turn it, and with a shroud I wonder how many rpm's the fan would achieve with a ~70mph wind blowing at it and no assistance from the engine. Likewise for prostock style hoodscoops. EFI data logs can show a couple psi of boost at high speeds with those things, which doesn't come up on dyno's.
John mentioned the huge radiator thing. Totally true. I have that big Ron Davis radiator. I turn my electric fan on about 1 percent of my drive time.
horsepower wise,,, no fan is best.... still use all the radiator that you can get and then some.... railroad philosophy:laugh:,,,, to me,,,, to me.... it is back to basics.... road/daily use ,,,, heavy duty all the way,,, with all components:Brow: racing,,, as close to no fan as possible....if a fan at all, electric.... and keep the battery charged.... I still use the old alt. field switch trick.....:laugh: but for reliable, heavy duty cooling on a very hot day, in a traffic jam, with the air going,, mechanical,,,,,,,, with all the rad that you can get on the car, plus a good shroud.... and as many fan blades as you can get.... driven by clutch/ or straight drive....:gp::laugh::laugh:
Agree with the railroad approach. My old Chevy truck has an old worn out 350 and a huge diesel radiator, I don't think that thing even needs a fan and I live in AZ! The huge radiator acks more like a huge heat sink lol Eletric is nice if you want the extra power, but if reliability is a concern I've always felt better with mechanical, especially with the off-roading I do I feel better with a mechanical. However with almost every auto manufacture now using electrical fans on there cars, the technology/quality/reliabilty is probably much better these days...
Of course the major reason that the switch to electric fans occurred was transverse engines. It's kinda hard to use a mechanical fan with 'em. I think the the switch to electric fans on longitudinally-mounted engines was done for consistency throughout the manufacturer's line.
My 2007 Silverado 4x4 with the 6.0L has a big electric fan, and I can tell you it hits the electrical system hard (IMO) for amps when it kicks on, and it's loud if you are standing next to it idling. And remember, this truck has a 160amp alternator.
Howdy folks. I'm going to toss in a dirty word here. On my 540 horse small block CHEVY I run dual 14 inch fans through 2 relays and a toggle switch since my fan controller failed. I'm using a large 4 row aluminum radiator with external trans cooler. And a 180 t stat. I run a temp of 195 even if it's over a hundred. I run the fan constant except for warm up. Even in stop and go I will not exceed 195. I am using a stock gm serp internal reg alternator. The clutched mechanical fan could not keep this beast under 210. Even if it was 60 out. My vote goes to electric.
