mechanical fan removed power increase
Im sorry but thinking that a fan that is running non stop doesnt impede the flow of air is JUST WRONG, and I am sorry but a fan that is locked onto a speed IS YET ANOTHER OBSTACLE for the air to overcome.
You are right if the fan ISNT running then the fan will just "free-wheel" and not restrict air flow, but if their is a fan spinning at say 20 mph and you are traveling at 60 mph there is a MAJOR difference in air speed. The fan is just going to jam air up in front of it and impede the flow of air. Its not going to jam it 100%, sure, but it is going to jam it enough to restrict the air flow enough for your coolant to run hotter.
If anything the running fan is going to cause turbulence and beat the ever loving crap out of the incomming air and slow it down.
Ever heard of a helicopter engine failing? Choppers dont just fall out of the sky like a rock, they glide down to Earth because the blades catch enough air to let the chopper glide... The same concept applies to ANY fan blades... if they arent blowing air at the same speed as the air passing over them they WILL cause resistance. Flat out fact of life right there...
Now I know this is a hard concept to grasp for some, but facts are facts.
Im probably wasting my time trying to reason with a lot of you on here, I know everyone on here is an expert... and the more posts you post the larger your IQ becomes....
Believe me or not, I really couldnt care any less if you can listen to reason or not. Its not my problem...
But ask yourself one thing...
If a fan doesnt impede the flow of air through a radiator as it turns at the wrong speed, THEN WHY IN THE WORLD would auto manufacturers put clutches on mechanical fans?
WHY???
Why not just weld the fan to their waterpumps and ship them out?
Why would you EVER want your fan to spin freely at highway speeds? HMMMMMMMMMM? Thats a toughy.
If you cant answer that then I dont know what to tell you.
Of course most on here figure they are smarter than every automotive engineer in the world, and more rational than a 100 years and thousands upon thousands of automotive developments...
Go figure..
Bottom line is: RADIATOR FANS ARE ONLY NESSECARY AT IDLE, ANY OTHER TIME THEY ARE A BURDEN.
You are right if the fan ISNT running then the fan will just "free-wheel" and not restrict air flow, but if their is a fan spinning at say 20 mph and you are traveling at 60 mph there is a MAJOR difference in air speed. The fan is just going to jam air up in front of it and impede the flow of air. Its not going to jam it 100%, sure, but it is going to jam it enough to restrict the air flow enough for your coolant to run hotter.
If anything the running fan is going to cause turbulence and beat the ever loving crap out of the incomming air and slow it down.
Ever heard of a helicopter engine failing? Choppers dont just fall out of the sky like a rock, they glide down to Earth because the blades catch enough air to let the chopper glide... The same concept applies to ANY fan blades... if they arent blowing air at the same speed as the air passing over them they WILL cause resistance. Flat out fact of life right there...
Now I know this is a hard concept to grasp for some, but facts are facts.
Im probably wasting my time trying to reason with a lot of you on here, I know everyone on here is an expert... and the more posts you post the larger your IQ becomes....
Believe me or not, I really couldnt care any less if you can listen to reason or not. Its not my problem...
But ask yourself one thing...
If a fan doesnt impede the flow of air through a radiator as it turns at the wrong speed, THEN WHY IN THE WORLD would auto manufacturers put clutches on mechanical fans?
WHY???
Why not just weld the fan to their waterpumps and ship them out?
Why would you EVER want your fan to spin freely at highway speeds? HMMMMMMMMMM? Thats a toughy.
If you cant answer that then I dont know what to tell you.
Of course most on here figure they are smarter than every automotive engineer in the world, and more rational than a 100 years and thousands upon thousands of automotive developments...
Go figure..
Bottom line is: RADIATOR FANS ARE ONLY NESSECARY AT IDLE, ANY OTHER TIME THEY ARE A BURDEN.
Administrator
Joined: Apr 2010
Posts: 87,398
Likes: 4,213
From: Clayton MI
Fan clutches are thermostatically controlled, they don't give a rat's behind about vehicle speed, nor do they have the slightest clue. if the air blowing over them is hot enough, the fan engages, regardless of vehicle speed.
A running electric fan is going to be LESS of a restriction than one that is free wheeling.... for the most part. I suppose, at some speed, it will take more air pressure to overcome the the electric motor, and spin the fan faster than it really wants to go, but, for most intents and purposes, a running fan is no restriction at all.
You are correct on one score though, a fair few vehicles disable the electric fan at speeds above 40MPH, simply because there is already enough air flow to cool the radiator, that is, until you turn on the A/C, then they run constantly, regardless of vehicle speed.
A running electric fan is going to be LESS of a restriction than one that is free wheeling.... for the most part. I suppose, at some speed, it will take more air pressure to overcome the the electric motor, and spin the fan faster than it really wants to go, but, for most intents and purposes, a running fan is no restriction at all.
You are correct on one score though, a fair few vehicles disable the electric fan at speeds above 40MPH, simply because there is already enough air flow to cool the radiator, that is, until you turn on the A/C, then they run constantly, regardless of vehicle speed.
Captain
Joined: May 2011
Posts: 652
Likes: 0
From: Central Florida
I had a 350 in a 91 S10 that I couldn't keep cool. Maybe the Griffin radiator was a little too small- I don't know for sure (even though the rep told me it was plenty big enough). It would get too hot in city traffic. It would get too hot driving down the road @ 55 mph even in OD. I put a Taurus fan on it and a 100 amp alternator and never went over 180* again. So apparantly the fan did some good at higher speeds because if I turned it off the temp would start climbing; especially pulling a trailer.
Legend
Joined: Jun 2009
Posts: 8,025
Likes: 72
From: orangeville ontario
tomorrow or the next day
ok 9 am tomorrow will have dyno run to determine the power gains of the mechanical fan removed. 213/293 is with spectre cai and flowmaster dual exhaust muffler delete, and some upgraded springs or rockers(still no word of what was put in). Totally cool performance dual e-fan setup is 500 something shipped. finally got the damn thing put in this last week after siting in box in bedroom for months. I have to say she can do a hell of a burnout now. never could get the tires to even break loose before with mechanical fan in. much quieter and smoother feel to the acceleration. Now have scanner/printer so i can finally upload the damn graphs. I filled the truck up to test fuel economy with this so any better then 13.5 is a major gain as that was absolute best i have gotten.
I am curious to see them as well.
Champion
Joined: Aug 2010
Posts: 2,697
Likes: 3
From: Cape Carteret NC
That dyno is going to need to graph at the very basement of RPMs if its going to catch the gains..
By my figuring, the fan (when thermo locked) at idle takes the same torque to turn as it does at 5k rpm and thermo locked.. it takes the same unlocked at either speed too.. the percentage of torque its robbing from the engine drastically decreases as rpms climb.. just my figuring now, but I figure the gains won't be visible so much above 1500rpm or so.. right at and off of idle, it will..
So.. the gain will be small off idle, but it will be a huge percentage of the present torque at that speed..
It will be tough to quantify, but the gain is real and present. I've been using efan for a good while now.. I've never come close to overheating with it.. I did it for cooling reasons alone.. the punch off idle was a nice little bump, and right in the range you need it most..
By my figuring, the fan (when thermo locked) at idle takes the same torque to turn as it does at 5k rpm and thermo locked.. it takes the same unlocked at either speed too.. the percentage of torque its robbing from the engine drastically decreases as rpms climb.. just my figuring now, but I figure the gains won't be visible so much above 1500rpm or so.. right at and off of idle, it will..
So.. the gain will be small off idle, but it will be a huge percentage of the present torque at that speed..
It will be tough to quantify, but the gain is real and present. I've been using efan for a good while now.. I've never come close to overheating with it.. I did it for cooling reasons alone.. the punch off idle was a nice little bump, and right in the range you need it most..
Record Breaker
Joined: Mar 2009
Posts: 2,181
Likes: 3
From: Battle Ground WA
That dyno is going to need to graph at the very basement of RPMs if its going to catch the gains..
By my figuring, the fan (when thermo locked) at idle takes the same torque to turn as it does at 5k rpm and thermo locked.. it takes the same unlocked at either speed too.. the percentage of torque its robbing from the engine drastically decreases as rpms climb.. just my figuring now, but I figure the gains won't be visible so much above 1500rpm or so.. right at and off of idle, it will..
So.. the gain will be small off idle, but it will be a huge percentage of the present torque at that speed..
It will be tough to quantify, but the gain is real and present. I've been using efan for a good while now.. I've never come close to overheating with it.. I did it for cooling reasons alone.. the punch off idle was a nice little bump, and right in the range you need it most..
By my figuring, the fan (when thermo locked) at idle takes the same torque to turn as it does at 5k rpm and thermo locked.. it takes the same unlocked at either speed too.. the percentage of torque its robbing from the engine drastically decreases as rpms climb.. just my figuring now, but I figure the gains won't be visible so much above 1500rpm or so.. right at and off of idle, it will..
So.. the gain will be small off idle, but it will be a huge percentage of the present torque at that speed..
It will be tough to quantify, but the gain is real and present. I've been using efan for a good while now.. I've never come close to overheating with it.. I did it for cooling reasons alone.. the punch off idle was a nice little bump, and right in the range you need it most..
I saw no difference during normal driving or any MPG change, the difference is that on the hot days when the clutch fan would lock up there was a huge power loss which isn't there with an electric fan, the whole point of the clutch fan is to only be working when it needs to so most of the time you aren't gonna notice it.
i will try and upload a dyno graph tomorrow morning. been away from laptop all weekend. well the answer is in 3 hp and 9 lb/ft of torque(215hp and 300ft/lbs). mpg's gained right of the back of 1. now that was beating the ever living life out of it in rush hour traffic on way up there, and friday morons doing 60 in a 70 left lane. plus dyno runs, 12.5 was the worst i think i could get. happy as hell with the totally cool performance dual electric fans and the controller, aluminum shroud set-up. now have gotten the power to finally do a burn out rear brakes always stopped me before, no matter how i tried to do it. i am going to see if i can beat 13.5 mpg's which is my best run of a tank to date. so no more lead foot for a bit to see how that can really gain. ps please keep your stupid coments to your self if you can't have respect for what i just proved.