Electric fans suck!

[L31MaxExpress]

So much for trying them again. Even with a 34x19 dual core radiator and dual 3,000 cfm 16" fans my 383 tried to lose its cool and that was not even pulling my travel trailer. I picked up a 31x17 dual core radiator to allow me to refit the mostly intact factory junkyard fan shroud I scored at the treasure yard yesterday. Ordered a severe duty fan clutch and found a Motorcraft YA249 11 blade fan thats mounting and bolt circle dimensions match the Vortec clutch. If you live in a hot area where you need ac 24x7, make decent power, have a heavy vehicle and tow, best to just leave the electric fans to the drag racers. With a decent mechanical fan and shroud my small block won't run over 190°F in the dead of summer. With the electrics screaming it got to 220°F yesterday before I backed off and let it cool down.

 

[0xDEADBEEF]

They work better at idle and stop and go, but for really hard work the mechanical is the best.

 

[L31MaxExpress]

They work better at idle and stop and go, but for really hard work the mechanical is the best.

Stop and go is where I was heating up. Creeping along at 5 mph, followed by acceleration, then braking and repeat 15x. A good mechanical pulls more air even at idle.

 

[L31MaxExpress]

The YA249 fan should work well. Has aggressively pitched, wide blades. I have a 20.25" opening in the stock shroud and the fan is 19.2" diameter. Its for a 3v 5.4 Ford and those seem to have great ac even at idle. They move some air. Sure it will eat a few hp when thr clutch fully engages, but its not like the 383 has any shortage of power. The 383 loses more power than the fan takes when the PCM starts pulling timing from running hot to keep it out of detonation. By 220°F the PCM is pulling 10° of timing.

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[L31MaxExpress]

When I had the bigger duramax fan blade on the old 350, I lost 15 ft/lbs and 7 hp at peak when it fully engaged on the dyno in hot weather however even on WOT power pulls it stayed under 190°F. Several of the vehicles dyno'd that day spit coolant on the floor on the 2nd and 3rd pulls.

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[0xDEADBEEF]

Stop and go is where I was heating up. Creeping along at 5 mph, followed by acceleration, then braking and repeat 15x. A good mechanical pulls more air even at idle.

I would think 6000 CFM would be enough to keep it cool at idle. I don't have any data but that feels like a high number for a mechanical fan to achieve at that rpm.

 

[L31MaxExpress]

I would think 6000 CFM would be enough to keep it cool at idle. I don't have any data but that feels like a high number for a mechanical fan to achieve at that rpm.

It will cool at idle all day long. Load it for acceleration and that is where it runs hot. I have a 2,800 converter, large trans cooler and a large ac condenser pumping heat out of dual evaporators in front of the radiator. The mechanical fan would be at 2,000+ rpm at that point and probably pulling 8-10,000 cfm. At 3,000 rpm compressor speed, the compressor is cranking out ~25,000 BTU into the condenser.

 

[AuroraGirl]

the fans are probably aftermarket cheapos.
I think you would find with your bigger radiator a mechanical fan on one side and an electric assist fan on the other with a shroud that properly covers to help and free up HP.

also you can get that idle performance helped, pusher fan as well. were the electrics fan blades the right direction????also
pic of your setup before and after? Pics or it didnt happen

 

[Dropped88]

Only electric fans I've used/seen where good has been the stock truck fans 05-13 and the only aftermarket fans that I know are good are spar fans but they are expensive.

Someone put cheap junk fans on my dually and excessively idling with the ac on makes the temp start to creep up

 

[AuroraGirl]

Only electric fans I've used/seen where good has been the stock truck fans 05-13 and the only aftermarket fans that I know are good are spar fans but they are expensive.

Someone put cheap junk fans on my dually and excessively idling with the ac on makes the temp start to creep up

how did they control them? The controlling is part of the problem i bet, in addition to shrouding, deflectors ,etc