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#1 |
upgrading to an older model
Join Date: Aug 2007
Location: Sacramento, KY
Posts: 346
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electric fan v/s motor driven
I've heard that using an electric fan instead of the motor driven will increase horsepower...Actually I think the theory is it decreases the horsepower lost to resistance created by the motor having to turn the fan. Either way there is supposed to be a gain in HP. Has anyone heard of this? If so how much HP do you think would be gained? (350 c.i. SBC +.030)
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68 stepside, short-box, multi-colored (for now) ![]() ![]() ![]() |
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#2 |
Boosted Member
Join Date: May 2002
Location: Mackinaw, IL
Posts: 2,200
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Re: electric fan v/s motor driven
You're on teh right path. An electric fan will free up some hp from parasitic losses, and will only come on when needed (via a thermostat). I'm pretty sure HotRod or some other car rag did a test on this not too long ago. I think the ballpark was 5-7 more hp by going to an electric fan vs. a NON clutched fan.
This will put an increased load on your charging system and the alternator will be slightly more parasitic to create the extra electrical power.
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1972 2wd K/5 Blazer Turbocharged 370 LSx - 941 rwhp / 1093 rwtq 1969 Chevy K-10 L33 5.3 / 4L80E / NP241 / 4" lift 1964 Buick Skylark Twin TURBO 383 LS pro-touring project 2014 VW Passat TDI - Daily Driver Turbo diesel 2015 Sierra Denali HD Duramax Turbo diesel 2016 Ford Explorer Sport - Twin Turbskis 2017 Polaris RZR Turbo 2014 Nor-Tech Center Console - Twin Supercharged Outboards TURBO ALL THE THINGS!! |
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#3 |
upgrading to an older model
Join Date: Aug 2007
Location: Sacramento, KY
Posts: 346
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Re: electric fan v/s motor driven
Actually I'm gonna use this set-up on my dirt-track car...no alternator, gonna run it off a seperate battery with a simple on/off switch
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68 stepside, short-box, multi-colored (for now) ![]() ![]() ![]() |
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#4 |
Registered User
Join Date: Aug 2007
Location: Greenfield, MO
Posts: 215
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Re: electric fan v/s motor driven
..........
no .......... alternator???????? ![]() |
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#5 |
upgrading to an older model
Join Date: Aug 2007
Location: Sacramento, KY
Posts: 346
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Re: electric fan v/s motor driven
2 batteries...one for the motor and one for the fan. Not to mention I can arrange them to provide weight where needed
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68 stepside, short-box, multi-colored (for now) ![]() ![]() ![]() |
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#6 |
Registered User
Join Date: Jul 2006
Location: Fair Oaks, CA
Posts: 475
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Re: electric fan v/s motor driven
clutch fans rob nothing until it gets hot enough then they can rob like the flex ones do which is around 20hp they did a test a year or so ago in chevy high performance so an electric fan does free up a little power but when on your alternator will have a little more draw on the motor but not enough to notice.
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1968 Short Fleet 350/700r4 http://67-72chevytrucks.com/vboard/s...d.php?t=249435 1997 Bagged XtdCab Vortec350/4L60e http://67-72chevytrucks.com/vboard/s...44#post2286144 1993 XtdCab Longbed 4x4 6.5Turbo/NV4500 "Daily Driver" 1985 Toyota XtdCab 4x4 22re/W-56/Dual T-cases, Doug Thorley Header, Homebrew front and rear spring packs, Tons of Mods to suspension and drivetrain, 35" boggers, coming soon ARB's and 5.29's, Possible 4.3/700r4 swap |
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#7 |
Fabricate till you "puke"
Join Date: Jun 2002
Location: Ill
Posts: 9,403
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Re: electric fan v/s motor driven
There is no such thing as "free lunch", when it comes to horse power. I run a dual elect fan setup on my longhorn, & it works great.....but it never runs wide open for more than about a 1/4 mile at a time(once in a while)
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69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears.... |
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#8 |
Parts and more parts
Join Date: Nov 2003
Location: Lebo, Kansas (middle of nowhere
Posts: 6,821
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Re: electric fan v/s motor driven
The average is around 5 to 7 horses freed up for the engine to apply elsewhere. You could also see an increase in fuel economy (I did on my trucks -- about a mile per gallon) and you will see a smoother running engine with that load removed. My DD warms up faster in the winter, also.
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#9 |
upgrading to an older model
Join Date: Aug 2007
Location: Sacramento, KY
Posts: 346
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Re: electric fan v/s motor driven
Sounds to me like there are advantages all around, more HP and better gas milage. I'll definitly look into going that route when/if I ever get the '68 going.
I turn around 5500rpm in my car at the end of the straight. my nephew popped his engine at 6400 (you could put your fist in the cylinder chamber through the side) so I try to not go that high. We run 7 green flag laps. it might take 25 laps to get those 7 in (caution laps don't count, and I don't think the flag guy counts too good...sometimes it seems longer/shorter). I don't know the CFM of the fan(s) actually there are two. I'm planning on wiring them through switches where I can turn them on and off as needed based on temp. Here's what the fans look like
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#10 |
Registered User
Join Date: Sep 2007
Location: Emporium,Pa
Posts: 248
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Re: electric fan v/s motor driven
Ok I can understand the HP/ mileage increase of the electric fans. But IMO if ya wanted to decrease even more parasiti power loss wouldnt it make sense to also run an electric water pump? Or under/overdrive pulleys? I guess Im not understanding just stopping at the electric fan solution. Im sure Ill get flamed for this post and I dont mean to step all over the original post but its just my opinion.
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"When you were born, you cried and the world rejoiced. Live your life so that when you die, the world cries and you rejoice." [Cherokee saying] 2001 Dodge Ram Sport 1500 4x4. (old ride) 1987 GMC V1500 Sierra Classic ("new" ride) |
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#11 | |
Parts and more parts
Join Date: Nov 2003
Location: Lebo, Kansas (middle of nowhere
Posts: 6,821
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Re: electric fan v/s motor driven
Quote:
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