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Thread: Does an electric fan really free up hp?

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    Default Does an electric fan really free up hp?

    Wondering if anyone did a before and after after this install time slip or dyno wise. Doesn't seem to me that claims of increased hp ratings are making total sense as isn't the alternator having to work harder to run the extra electrics? That has to use up some of the gains no? I've heard numbers from 15-25 hp increase but this seems outlandish to me. Sort of when the "cool can" craze hit the 60's and 70's. Never any proof that it actually helped times as opposed to other factors such as better leaves or track conditions.

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    yes. no.


    Electric fans are only on when you need it. they are off when you don't need it. a mechanical fan is 'always on' even though they have a clutch on them that allows them to freewheel at less rpm than the engine unless temps are high and it locks up the clutch to move more air.

    so, always on, always causing drag on the engine, vs an electric that's off when you don't need it and therefor no drag on engine.

    when the fan is on, it's using electricity. the alternator has to create more amps to feed the fan, and that increased load adds drag on the engine, so when the fans are on, you still add load to the engine.

    drag racing? you're likely cool enough at the start line that your fan isn't on yet, and you aren't adding load to the engine. or, like some race set-ups, they run no alternator, running straight off battery alone and there's zero load on the engine from the fan. but, those guys also recharge the battery between rounds.
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    BIGROB's Avatar
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    15-25hp might be a stretch but I'd put money on at least 8-10hp improvement.
    This is the 3rd Dakota I've put an electric fan on and I've been pleasantly surprised each time. Feels smoother, revs a little faster, and quieter. Biggest difference was felt on my 3.9 v6 truck. I'll always run an electric fan and now most OEM's are also.

    This isn't comparing to electric but proves how much parasitic drag a fan can be.


    Project Maverick. I feel the need, the need for speed

  4. #4

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    Well that's that then. I don't suppose anyone makes a specific kit for these things that points out how to hook one up with these modern day electronics? Never was good with electronics as never had to deal with this stuff. Things were so much simpler at one time. Battery, switch, wire to what you wanted to run..done. Now there's relays, sensors, computer crap, ad nauseum.

    I need one of these "Electric fan for Dummies" fan. Thanks .

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    Quote Originally Posted by arro222 View Post
    Wondering if anyone did a before and after after this install time slip or dyno wise. Doesn't seem to me that claims of increased hp ratings are making total sense as isn't the alternator having to work harder to run the extra electrics? That has to use up some of the gains no? I've heard numbers from 15-25 hp increase but this seems outlandish to me. Sort of when the "cool can" craze hit the 60's and 70's. Never any proof that it actually helped times as opposed to other factors such as better leaves or track conditions.
    An electric fan is what finally got me from the low 14s to the high 13s. Worth it in my opinion.

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    BIGROB's Avatar
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    Quote Originally Posted by arro222 View Post
    Well that's that then. I don't suppose anyone makes a specific kit for these things that points out how to hook one up with these modern day electronics? Never was good with electronics as never had to deal with this stuff. Things were so much simpler at one time. Battery, switch, wire to what you wanted to run..done. Now there's relays, sensors, computer crap, ad nauseum.

    I need one of these "Electric fan for Dummies" fan. Thanks .
    DC voltage systems are the same today as they were in the 60's. Can be as simple as fan, switch, battery if you want it to be. No prepacked kits for our trucks are available but they would be overpriced anyway.

    This is what I have.
    https://www.summitracing.com/parts/f...MobileSwitchNo

    Project Maverick. I feel the need, the need for speed

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    nitroram33's Avatar
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    I've got a Black Magic 160 and it doesn't cover anywhere near enough of the radiator to keep the truck cool sitting still in traffic. Buy an '06 HHR fan.

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    Duner's Avatar
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    I'm running dual 11" fans in a custom shroud to keep my hooptie cool in AZ heat with my AC on. At the track I simply toggle them off for a pass down the track to free up what little additional draw they put on the alternator, then turn them back on when I make the return road.
    Duner
    4.7 Turbocharged CC in white - 12's
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    1999 Dodge Dakota R/T RC Turbo: 10.51 @ 130.13 MPH

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    Quote Originally Posted by Duner View Post
    I'm running dual 11" fans in a custom shroud to keep my hooptie cool in AZ heat with my AC on. At the track I simply toggle them off for a pass down the track to free up what little additional draw they put on the alternator, then turn them back on when I make the return road.
    does the first 2 seconds when you're below 40 mph even last long enough to put heat into the water? once you're over 35-40, airflow through the radiator is way more than a fan can make anyway, and at 130 mph....that's plenty of airflow to cool you down. water temps at the line vs stripe are....?
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    Duner's Avatar
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    Quote Originally Posted by Filthy Filbert View Post
    does the first 2 seconds when you're below 40 mph even last long enough to put heat into the water? once you're over 35-40, airflow through the radiator is way more than a fan can make anyway, and at 130 mph....that's plenty of airflow to cool you down. water temps at the line vs stripe are....?
    You are correct. The fans whether on or off wouldn't actually be helpful at all at speed. I wouldn't need the twin fans and shroud if I was only drag racing it. It gets lots and lots of street miles on it, and in the heat with the AC blowing nice cold air on my candy ass self. Hahaha So what it does at the track is kind of secondary. I probably could free up some weight if I pulled all that off for the track, but I'm just too lazy to do all that for a coupld of hundredths.

    At the track - the warmer the truck is - the quicker and faster it goes. The problem is that there's a fine line there before it hurts itself. The highest mph pass it's ever made 133.65 mph - and it cost me 2 pistons. I left the line at 205° and it hit 230° by the stripe - while blowing holes in the top of those 2 pistons. The centers melted like tear drops because the pistons couldn't shed enough heat. Crankcase oil squirters spraying the bottom of the pistons would help or fix that, but I'm just not that interested in engineering the fix right now. I'm getting lazy in my old age.

    I make sure it's at roughly 180° after the burnout. So there is heat in it. Whether I ran the fans for the burnout will depend upon what time of year it is. It does make plenty of heat by the stripe. Usually around 200°. It puts quite a bit of heat into the cooling system - since the cooling system was designed for 250hp. LOL
    Duner
    4.7 Turbocharged CC in white - 12's
    5.9 Turbocharged RC in black - 10's

    1999 Dodge Dakota R/T RC Turbo: 10.51 @ 130.13 MPH

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    230 and you melted pistons? something else went wrong, right? dropped a couple injectors? sucked air into fuel line from slosh?
    --Tom
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    ScojoDak's Avatar
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    Quote Originally Posted by Filthy Filbert View Post
    230 and you melted pistons? something else went wrong, right? dropped a couple injectors? sucked air into fuel line from slosh?
    Extreme heat and detonation go hand in hand. Timing may have been marginal.
    If you haven't lived for something, you'll die for nothing.

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    yea, I guess I never thought of detonation as causing pistons to melt. break them up like hitting them with a hammer, pound the bearings out, etc. but I hadn't heard of detonation melting parts. My understanding of detonation is that it's not super hot like running lean, it's where you have hot spots in the chamber and you end up with 2 flame fronts colliding with each other.
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    Duner's Avatar
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    Quote Originally Posted by Filthy Filbert View Post
    230 and you melted pistons? something else went wrong, right? dropped a couple injectors? sucked air into fuel line from slosh?
    You are correct that there was also something else involved. Very astute!

    There were no signs of detonation in any of the chambers, pistons or plugs. Although to be honest, the two that were hurt were covered with oil. The holes in the top of the pistons also let the charged air/fuel mixture be ignited in the crank case. Both the front and rear pan gaskets were outside of the pan rails after the multiple boom booms in there. Yay! Oil everywhere and a smoke show!!! NO mosquitos in the area, and luckily, no crash.

    Upon disassembly, it was found that the two pistons that melted were actually the wrong size!

    I paid the extra money to have the machine shop assemble it after they machined all the parts. That was a huge mistake on my part. I don't know if they had a "rookie" assemble it or if they just normally do sloppy work. They apparently only measured a single piston and did final hone on all 8 from that. I had 6 - 4.027" diameter pistons and two 4.017" diameter pistons. Huh? They were all still "round". Care to guess which two melted? hahaha I surmised that those two pistons simply couldn't shed enough heat to the cylinder walls? And yes, it did "rattle" on cold start up. I just figured it was loosy-goosy forged pistons waiting to expand in the bore. LOL It still rattles on start up. Everything is to the far side of tolerances. It's rattled this long..... I'll just pretend I don't hear it and mat the throttle.

    Another fine thing I found during disassembly just blew my mind.... Somehow they managed to get one of the rod caps on backwards and it didn't do anything more than make the side clearance too tight. Nothing came apart. The bearings on that journal still looked OK. That was the very first time I ever let somebody else assemble an engine for me, and obviously will be the last!

    In any event, I've been very conservative about letting it build too much heat since them anyway.

    Sorry to pull the electric fan thread off topic!
    Duner
    4.7 Turbocharged CC in white - 12's
    5.9 Turbocharged RC in black - 10's

    1999 Dodge Dakota R/T RC Turbo: 10.51 @ 130.13 MPH

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    98Dak408's Avatar
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    I was happy with the improvement an electric fan and an underdrive pulley made after the swap. No proof of dyno or ET numbers but I could feel it in the seat of the pants. Revved a little faster and pulled a little harder. I had previously been running the OEM clutch fan.

  16. #16

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    Quote Originally Posted by 98Dak408 View Post
    I was happy with the improvement an electric fan and an underdrive pulley made after the swap. No proof of dyno or ET numbers but I could feel it in the seat of the pants. Revved a little faster and pulled a little harder. I had previously been running the OEM clutch fan.
    They seem simple enough to install as long as I don't have to dick with sensors or computer crap. Seems the biggest problem is with mounting bracket bends. Should do it after I install the cam however since all that crap has to come out anyway.

  17. #17

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    2006 HHR Fan, does it come with the relay already installed, or does it need to be wired to an external temp relay?

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    Quote Originally Posted by 99 IB RC View Post
    2006 HHR Fan, does it come with the relay already installed, or does it need to be wired to an external temp relay?
    Will need an external relay/controller
    This signature has been deleted thanks to photobucket!

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    Thanks.
    Now to start shopping.

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    I've got a used black magic fan and controller I bought to free up some ponies in my ram...I bought a 24 valve RAM instead.

    So I'll be posting it up once I get pics and details.
    11.27 @ 118.23
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    Quote Originally Posted by Duner View Post
    At the track - the warmer the truck is - the quicker and faster it goes.
    so what's the logic on that? I know there's that thermal efficiency or whatever its called, but I all of my vehicles and motorcycles included certainly feel slower once they are warmer, higher intake temps, heat soaked, ???

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    Duner's Avatar
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    Quote Originally Posted by spawn_x View Post
    so what's the logic on that? I know there's that thermal efficiency or whatever its called, but I all of my vehicles and motorcycles included certainly feel slower once they are warmer, higher intake temps, heat soaked, ???
    The air/water intercooler and high rate of fuel flow takes the heat soak or higher intake temps out of the equation.
    It's most likely a thermal efficiency thing.
    Duner
    4.7 Turbocharged CC in white - 12's
    5.9 Turbocharged RC in black - 10's

    1999 Dodge Dakota R/T RC Turbo: 10.51 @ 130.13 MPH

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    Quote Originally Posted by Duner View Post
    The air/water intercooler and high rate of fuel flow takes the heat soak or higher intake temps out of the equation.
    It's most likely a thermal efficiency thing.
    My blown e55 had an air/water intercooler, and it HATED being warm, but the i/c was less than optimal, and I probably wan't moving as much fuel as you

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