Good stuff!! I have 2 of those plastic flex fans..what I like is they weigh a few oz cool very well, move lots of air with less stress on the water pump bearings.
Think where many get fooled is crate engine ratings where they dont have accessories done in a dyno cell w/ideal conditions. In a hot engine bay w/everything hooked up Id bet a 50hp loss or more is common. See guys posting from time to time how their 400hp crate didnt feel like 400...
Cooling is a huge deal to me so losing a few to stop gauge watching is worth it to me;electric water pumps always puzzled me..why, for the $ vs the tiny gain

 

At least.

 

I can't watch the video until later today, but where can someone get those plastic flex fans? I'm surprised I haven't seen them being discuss here (or I missed it). Is there a downside using one?

 

I've wanted to mod in a EV fan clutch. It's like a thermal clutch but electronically modulated so you can command lock and then unlock when not needed. Best of both worlds. Obviously wouldn't work on a stockish c4 though. Serious mods required but they move massive air.

I doubt they get much traction here since they're for a belt driven fan setup.

 

Davies makes a pwm controlled water pump for sbc, bbc, and they can build it to also pwm control the fans. That would be the best of both worlds. Rated for street duty with a very high hour rating, and the pumps are rebuild able.. if saving 25 hp is worth a grand to you go for it bro. Personally I'd rather have the overkill of a high volume belt driven pump. And pwm controlled fans. But.. I plan on actually driving my build in traffic. If max power in short bursts is the goal there is definitely power to be had with electric pumps and fans

 

Vette 196 they sell those plastic fans at Summit, made my Flexalite. No downside dont know if they make reverse rotation ones
Also wondered about adapting a clutch to them...the old 70s Capris MB BMW had fans like that...white plastic blades and a clutch.

They dont break like the riveted metal ones can, mine gotta be 20 yrs old

 

Yes. They lost 24 hp, using it. It was the second most parasitic fan that they tested.


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Gonna call Summit and see if they make a reverse rotation one (isnt that what 88 uses?)
Id mount the elec up against the radiator and the plastic one in its place

 

I like how you post a video up of them losing power, and suddenly everyone is wondering where you can get one.
Electric fans FTW, especially with massive brushless fans out there like Delta PAG which are easy to use in any car.

 

The only down side is even the best won't even touch the cfm of a decent mech at speed. That being said... you'd never need that much cfm unless you have a really crap cooling system... like my old truck... many tried Efans... never quite would cut it. Meanwhile mine was chucking snow out of the air vents at me in 100+ degree heat. IDK who in their right mind would want to go back to a mech fan. Another thing you have to worry about letting loose under a pull? No thanks.

 

Depends. A pair of good electric fans moves more air than a LOT of mechanical fans, especially at idle where the fan is needed the most.
A mechanical fan will move more air at a high engine RPM, and less at low engine RPM.
Also, fans are most needed at low vehicle speeds. At highway speeds and low RPM, a mechanical fan can actually be moving slower than the incoming air and cause a restriction.
This is why electric fans on newer cars shut off above a certain MPH.

So unless you're doing high RPM low speed tractor pulls in your car, you'll get more benefit with an electric fan in the cooling department, not to mention the bonus horsepower.

 

Sure in general electric is better especially 2 of them.

Have an older car with a new Dewitts, 16" spal that struggles to stay cool
The plastic flex alone was night and day better, that tiny hit of power imo worth it...may be older tech but they wont break period.

Those Deltapaqs look pretty promising have you used their controller? Seems like a good piece as far as single fans go.
Id think a nice OEM piece off a V8 truck, luxury car would be more than enough and have longevity. Cant say I have a lot of faith in most speed shop stuff.

 

The one on my old truck moved a measured (bunch of us tested it) 4500 cfm at 1000 rpm and about 5200 at 1500... there weren't a ton of fans that could be made to fit that move anywhere near that at the time. Now I'm sure there are some that are better. But 10000 cfm at 2k (thing sounded like a freightliner going by) was so overkill lol. Idle cfm was only about 2200 though. Where a mech fan won't be better. But the guys using efans were the off roaders running in 4 low where your rpms are in the 2200 range. The other issue was that a civic had a bigger factory radiator than that thing so it really needed a crap ton of flow to not overheat.

As I said earlier, it was an electronic viscous coupled clutch. Meaning under hard acceleration or highway speeds it just freewheeling anyway. It was programmed like a efan just driven by a belt. Worked great when it worked but being it was new tech they abandoned it and went to a standard thermal clutch. I have the fans in the vette programmed to kick off around 40 mph. I did testing in the summer to see where temp would come down moving with them off and it seems about 30 mph is where it would be sufficient on a hot day and 40 is where it'll actually cool faster than if the fans were on.

Not arguing or anything. That truck as designed would've never worked with efans. Guys were running dual venture fans and it wouldn't keep cool. (About the best flow available at the time)

I run both on the 67. it had just 2 16 inch spals on a custom shroud and that.... kind of worked. After talking with several guys and seeing the pitch on a stock 67 mech fan I put one in on a thermal clutch and left a single spal as a pusher to add flow at low speed. Now even that runs cool finally. If it had a better grill configuration fans probably would've worked. I feel like at idle they moved adequate cfm just didn't launch air under the car like the mech did once the clutch locked. I think a lot would end up hovering around the rad and get sucked back through.

 

Yeah, I noticed that and thought it was funny too.

But I "get it" for a truck application; towing you can often be at lower speed, high load....making HUGE BTU's with marginal air flow....you need a fan. A big'n that uses a lot of HP. You should see the fans on our snow cats. They're making 350-500hp and with a 12 mph top speed...they need fan performance that no electric fan could provide.










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I could care less about 8 hp gain if my electric fan burned up and left me stranded

 

There are brushless fans now that move >4000 CFM. A pair of small 12" brushless fans staggered on a radiator will move ~5000+ CFM.
For small (and very thin) fans on cars, this is amazing.

I got to spend a little time talking to the guys about these Delta PAG fans are PRI last year. I was amazed out how much air these things moved and how quiet they were.
Not to mention the amp draw was tiny compared to most fans I've ran in the past.

Walking around PRI, I started to notice that a lot of the Drag Week cars there were running these fans, with nothing but good things to say about them.
I'll be running a pair of them on my radiator in my next setup.

I haven't used their controller, but only because my ECU is capable of controlling them via PWM, so I don't have any need for it. I just need the fans.

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Spoke to a rep there about a yr ago; fans sound stout, but he didnt sound real confident with thier controllers with the "most guys buy 2 in case". bit...they are not cheap!!
Wonder if another brand controller would work.

 

I'm guessing 4000cfm combined. Just looking around I'm seeing cfm averages in the 3000 range.