Video - Horsepower Loss To Fans.....

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Zero. In fact, one that's on the ragged edge of overheating will make more power every. single. time.

MRGTX said:
How much more horsepower do you suppose a 180* engine makes than one that's boiling over? I think you could make an argument that fans give horsepower. It's a critical part of the power system.

Otherwise, you'd have to admit that only gasoline "gives" power.

But yeah, this is a measure of minimizing how much power they waste.
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definitely interesting and good to know. i will be running a clutch fan on my 400 hp 340 in my dart but really i dont think i would really notice if i had a 30 hp loss if i ran a steel fan on the street. The first comments are so true for today the one guy says its not a bundle of power at 350 hp really? what does it take to be a bundle of power 500? lol
 
They did say at the end of the show that they were only testing in a specific rpm. So while at cruising in town speeds and rpm range the loss is much less. But as you increase rpm and load the power loss becomes much more. If you are going to car shows, the market, parts store I think the hp loss is minimal with a belt driven fan. But for the guys who are running their rig at the drag strip, or street racing where you're up in the rpm's you are just killing hp and I think we can all agree that is not the time you want hp sacrifice. There is a risk with either way you go wether it's a belt breaking or an electrical gremlin. Like its been said before, your rig run what you want. But if you want to keep the h.p go electric, if you are just driving it for more show then go run a belt drive.
 
318willrun said:
I think the point was it's still a hp loss. You do NOT add hp to a motor by adding a fan. You just don't take as much hp away. In other words, you can get back some of the loss hp by different types of fans. And as I said, you usually get back more of the loss by going electric, but you can minimize this by under driving the fan and selecting the right type of fan and shroud.
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I'm fully aware of that. I was just responding to RustyRatRods comment about how much hp an alternator costs at full load. Has anyone tested that? I don't imagine it'd be any more than a few. Id be interested in results of that test.
 
My car picked up .06 going from a 6 blade light duty stainless flex fan to a single 16 inch Ford fan. Above 40 mph cruise the fan cycles off. The flex fan stays in the trunk as a get home part. I drive 50 miles to the track and live in frigid Florida.
 
mopowers said:
I'm fully aware of that. I was just responding to RustyRatRods comment about how much hp an alternator costs at full load. Has anyone tested that? I don't imagine it'd be any more than a few. Id be interested in results of that test.
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I never said it was a lot or even comparable to either type fan. You're lookin so fuckin hard for an argument, you missed my point.
 
Exactly. Which is why you see serious drag cars without belt drive accessories, up to and including water pumps and alternators. For anything but a points drag car, belt driven fans are fine.

I know this. I can SEE a belt going bad BEFORE it breaks. You cannot see a fan motor, fan relay or fan switch going bad before it fails.


Penstarpurist said:
They did say at the end of the show that they were only testing in a specific rpm. So while at cruising in town speeds and rpm range the loss is much less. But as you increase rpm and load the power loss becomes much more. If you are going to car shows, the market, parts store I think the hp loss is minimal with a belt driven fan. But for the guys who are running their rig at the drag strip, or street racing where you're up in the rpm's you are just killing hp and I think we can all agree that is not the time you want hp sacrifice. There is a risk with either way you go wether it's a belt breaking or an electrical gremlin. Like its been said before, your rig run what you want. But if you want to keep the h.p go electric, if you are just driving it for more show then go run a belt drive.
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RustyRatRod said:
I never said it was a lot or even comparable to either type fan. You're lookin so fuckin hard for an argument, you missed my point.
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Calm down Crusty. Your comment just made me wonder how much power an alternator takes to spin at full load. Nothing more. How's you blood pressure these days?
 
I thought this was an interesting episode too. Then I thought, what happens when a vehicle is moving at a certain speed, 30-40 mph and above, then the air is being forced through the radiator and the fan doesn't have to 'work' to pull air through the radiator? Once there is neutral, and then positive pressure on the front side of the fan, I bet the power loss is MUCH less.
 
FWIW, Freiburger mentions in the video that the alternator draw to run an electric fan would be about one HP and barely noticeable on the dyno.
 
I say somebody goes to the track, make a pass. Allow cool-down time, remove the fan itself, and make another pass. Only Dyno I know, and have ever known is the E.T. slip
 
mderoy340 said:
post 32
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was this the same day, same wind, same temp, same humidity? If so, then a 1/2 of a tenth (.06) is not worth the discussion of fans, and 30 hp is more than a 1/2 tenth.
 
YoloCtyFlash said:
FWIW, Freiburger mentions in the video that the alternator draw to run an electric fan would be about one HP and barely noticeable on the dyno.
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I'm sure he probably is right, but has he measured it? I am sure the HP draw is much less than a belt driven fan, but hard numbers would be nice.
 
318willrun said:
I say somebody goes to the track, make a pass. Allow cool-down time, remove the fan itself, and make another pass. Only Dyno I know, and have ever known is the E.T. slip
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Well, yeah, if you want to do it the 'right' way. What fun is that?
 
With the new radiator I'm installing this weekend, a clutch fan won't fit....and I'd like to get rid of the scary flex fan ASAP....so I'm going to go electric.....not this weekend - no money for that right now!

Jeff
 
A belt driven fan without clutch will definitely use more HP than an alternator... that is why the VAST majority of so-called modern cars have electric fans. They only switch on when needed, that is only in stop'n'go traffic, maybe up the hill (not with a decent radiator) but surely not down the quartermile. And nowadays electric stuff don't break that easily... :)

PS. exemptions of the rule still apply...
 
YoloCtyFlash said:
At the 4:30 mark in the vid.
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He was very vague. He said the fan usually draws around 25-30 amps. The fan isn't the only thing drawing amperage. Ignition system, lights, blower motor radio and on and on. When I said full load that's what I meant. That's the only way to make a fair comparison. When I load test an alternator for a customer, it will pull the idle down a few hundred RPM. That's a load. That's what I am talking about.
 
Actually,the reason most modern cars have electric fans is because the engines are installed sideways and there's no room for a belt fan. Plenty of trucks still have belt driven fans.

stixx said:
A belt driven fan without clutch will definitely use more HP than an alternator... that is why the VAST majority of so-called modern cars have electric fans. They only switch on when needed, that is only in stop'n'go traffic, maybe up the hill (not with a decent radiator) but surely not down the quartermile. And nowadays electric stuff don't break that easily... :)

PS. exemptions of the rule still apply...
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MrJLR said:
With the new radiator I'm installing this weekend, a clutch fan won't fit....and I'd like to get rid of the scary flex fan ASAP....so I'm going to go electric.....not this weekend - no money for that right now!

Jeff
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Then drop the coin for a GOOD one. The Flex a lite Black Magic fans are great. Get as close to 4K CFM as you can. They ain't cheap, but you won't regret it.
 
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