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#1 |
Registered User
Join Date: Jan 2007
Location: Whitehorse, Yukon, Canada
Posts: 166
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HP gain with electric fan and water pump
Anyone know if the electric fan and electric water pump are a reliable conversion? I'm running a medium performance 283 just about to do break in.
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"gotta love something that works without a computer" |
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#2 |
69 Fleetside
![]() Join Date: Mar 2009
Location: Lake Stevens, WA
Posts: 333
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Re: HP gain with electric fan and water pump
Electric fan is safe in my opinion, as long as you get some good name brand ones. I questioned the electric water pump however, cause if it fails, the engine will still overheat driving or not...Edelbrock belt driven water pump, and 2 Spal fans here - should be safe enough even if one of the fans crapped out!
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#3 |
Registered User
Join Date: Jan 2008
Location: Tejas
Posts: 691
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Re: HP gain with electric fan and water pump
Even on a good meziere unit rebuilds are in short intervals for street usage, atleast on a daily driver. I would stick to mechanical
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'72 cheyenne super step, '05 long bed gmc |
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#4 |
Registered User
Join Date: Jan 2007
Location: Whitehorse, Yukon, Canada
Posts: 166
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Re: HP gain with electric fan and water pump
Can I use a new style pulley from a stock 350 on the 283 without running into installation problems for the power steering pump and alternator. The heads are new vortec heads with bolt hole configuration of the 350. Do the pulley sizes need to be a certain size for speed to water pump etc.
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"gotta love something that works without a computer" |
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#5 |
Account Suspended
Join Date: Jan 2007
Location: Tucson
Posts: 2,183
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Re: HP gain with electric fan and water pump
They are both reliable but if you are looking for a gain in HP by doing the conversion don't. You actually lose HP when converting. Why? It takes more power from the belt to spin the alternator to make up for the increased electrical load and the power conversion efficiency of the alternator isn't 100% so you take it in the...uhm...ear.
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#6 | |
Registered User
Join Date: Feb 2008
Location: Jackson, TN
Posts: 99
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Re: HP gain with electric fan and water pump
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#7 | |
Account Suspended
Join Date: Jan 2007
Location: Tucson
Posts: 2,183
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Re: HP gain with electric fan and water pump
Quote:
The alternator load on the drive belt is not a constant. It varies directly with the current draw on the alternator. The output power of the alternator in watts is the product of the output voltage and load current. My fans draw 25 amps when both run. At a constant 14V output this gives 350 watts. 746 watts is one horsepower so it takes about 0.5 hp to run my electric fans. According to Delco Remy the power conversion efficiency of my alternator is 65% which means for every 1 hp input at the pulley I get 0.65* 746 watts (484 ) out or just divide the power needed to drive a load like my fans by the decimal equivalent of the power conversion effiency of the alternator. In my case, 0.5 HP/0.65 = 0.75 HP from the engine. As you can see, the changes are small, but cannot be ignored if you're going to do an apples to apples comparison. Most drag racers prefer the electric fan and pump because the battery acts like a flywheel by smoothing out the load currents and spreading the fan and pump loads over a time period LONGER than the time required to do a 1/4 mile pass and there is no chance of damaging the engine by throwing a belt and losing circulation in the cooling system. This information came from two sources. AC Delco provided the specs on my 105 amp alternator and the conversion factors came from my Thermodynamics text. Without bragging, I need to introduce myself. I am the Technical Director of Special Systems at Raytheon Missile Systems Company in Tucson. I have a Masters degree in Electrical Engineering from USC and I did Graduate level work at Stanford in Aerospace Engineering. So, that makes me a rocket scientist that likes to play with old trucks! Last edited by Fitz; 05-27-2010 at 06:05 PM. |
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#8 |
Registered User
Join Date: Aug 2009
Location: Simi Valley, CA
Posts: 193
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Re: HP gain with electric fan and water pump
Fitz has it nailed. In fact when the fans kick on the idle in my truck drops about 150rpm due to the increased load on the alternator.
I built my own fuel injection system for my MGB and because of the data logging I could derive HP and torque so I could have my own personal dyno. This was very useful for tuning. I took a reading before removing my engine driven fan and one after and the total loss was 9hp. You don't really see the loss before 3000rpm but it is always there. I am an aeronautical engineer for Aerovironment that likes trucks! |
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#9 |
Registered User
Join Date: Jan 2008
Location: Tejas
Posts: 691
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Re: HP gain with electric fan and water pump
People don't just convert to electric accessories for no reason. They make power
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'72 cheyenne super step, '05 long bed gmc |
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#10 |
Big Red - Now its a SWB!
Join Date: Jun 2009
Location: Oroville, Ca
Posts: 1,624
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Re: HP gain with electric fan and water pump
This is all true, but you guys forgot one thing: the electric fans only run when needed, a fixed mechanical fan runs all the time. most of the time if you are going down the road the electric fan will be off, thus freeing up power. I would say go with the e-fan but keep the mechanical water pump. Oh and I guess I have the best power maker, an electric fan that isn't hooked up! LOL, I just haven't got around to it, but I don't sit and idle so it's been okay. Now that it is warming up outside I need to hook it up.
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68 3/4 ton ![]() ![]() 41 3/4 ton ![]() 01 Tahoe LT 4WD (my daily driver)-Magnaflow Muffler, Rollin on 22's 02 Ford Mustang Convertable (Wife's Car)-Flowmaster 50, Clear corners, Intake, sittin on 18's Last edited by Jacfourteen; 05-27-2010 at 08:10 PM. |
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#11 |
Registered User
Join Date: Feb 2008
Location: Jackson, TN
Posts: 99
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Re: HP gain with electric fan and water pump
Fitz. Not trying to imply you were wrong. I understand the math involved I'm a retired Naval electronics Chief Petty Officer, with a graduate degree. What I would like to know - for comparison purposes - is there a positive net difference in h.p. change between the belt driven pump and fan, and the electric? How much horsepower does the belt load steal, vs. the electric driven. It would be interesting to see the comparison.
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#12 | |
Senior Member
Join Date: Aug 2002
Location: Valley Center KS
Posts: 3,525
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Re: HP gain with electric fan and water pump
Quote:
This coming from a nuclear-mechanical engineer....and as I explained to my mom, a nuclear engineer is just one step above a rocket scientist ![]() |
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#13 | |
Junior Member
Join Date: Dec 2006
Location: Southeast Missouri
Posts: 2,436
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Re: HP gain with electric fan and water pump
Quote:
Electric fans and water pumps don't work if the alternator goes out, but an engine can run a long time off the battery if the fan and water pump are mechanical. Danny
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'67 Chevy C-20 short stepper - build complete, 454/SM-465. '75 C-30 Single Cab DRW-350 small block/NP-435. '77 GMC-6500 Dump Truck, 427 Tall Deck. '92 GMC K-3500 Duallie, 454/4L80E. |
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#14 | |
Hollister Road Co.
Join Date: Apr 2005
Location: Houston
Posts: 6,134
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Re: HP gain with electric fan and water pump
Quote:
DC electric motors generate their own voltage when spinning under load which is approximately 2/3 the input voltage. Start up or Locked rotor state requires full voltage and current because it doesn’t generate this voltage until the motor is up to speed. In layman’s terms the fan motor requires full voltage and say 100 amps to start up momentarily but once spinning it starts generating power and reduces its required input voltage and current by 2/3’s. That’s why you get that huge spike when a Mark VIII fan starts up. So while Fitz is correct, it is a very short duration that the fan is parasitic to the engine where a mechanical is always parasitic to the tune of 15 hp in most cases. For most automotive application in real world use they save a bunch on HP and MPG. Electric fans run maybe 10 minutes per hour while mechanical fans run 60 without a fan clutch and 30 -45 with a fan clutch. I’m all for electric fans in most applications but not water pumps. SBC engines nee the variable rate water flow that a belt drive offers. Electric pumps are constant rate that may not be enough in a traffic condition. "I'm not a rocket scientist but I did stay at a Holliday Inn Express" ![]() Sorry I couldn't resist Last edited by dwcsr; 05-27-2010 at 09:20 PM. |
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#15 | |
Registered User
Join Date: Jan 2006
Location: Take Off
Posts: 1,908
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Re: HP gain with electric fan and water pump
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#16 | |
Account Suspended
Join Date: Jan 2007
Location: Tucson
Posts: 2,183
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Re: HP gain with electric fan and water pump
Quote:
The point is we're talking about 2-3 HP. Can anyone here honestly tell the difference when the motor is banging out 300hp? I doubt it. It's just 1% of the total output and it get's even more rediculous when you start arguing about trucks made to run at the track. The 572 in my 67 C-10 is putting out somewhere north of 650 Hp. I can't tell the difference between 600 and 650 cause the whole shootin match is limited by tires! |
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#17 |
Account Suspended
Join Date: Jan 2007
Location: Tucson
Posts: 2,183
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Re: HP gain with electric fan and water pump
[QUOTE
"I'm not a rocket scientist but I did stay at a Holliday Inn Express" ![]() Sorry I couldn't resist[/QUOTE] OK. For all you guys who stayed at the Holiday Inn last night let's do a little experiment. Your truck's ignition can run on battery for a while without hurting anything and the same is true of the fan...you can do without both for a short time. Disconnect the belt that drives fan and alternator. If your power steering isn't driven by the same belt this works but if it is you'll be looking like Homer Simpson when he shut off the cooling water at the Nuclear plant...DOH! Get your son, neighbor, girlfriend or someone to flag you off and measure your 60 ft time. Then do it again with everything back together. This works even better if you're close to a dragstrip and they do Test and Tune nights as the timing system gives 60 ft times and 1/4 mile times. 10 Hp is good for 0.1 seconds in the 1/4 mile, so I don't think you can even measure the difference at 60 ft. If there's a measureable difference the Heineken's are on me. All you gotta do to collect is show up in Tucson! Now, what truck guy can pass up FREE BEER? Go on out and prove me wrong! Just don't get arrested.... |
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#18 |
Hollister Road Co.
Join Date: Apr 2005
Location: Houston
Posts: 6,134
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Re: HP gain with electric fan and water pump
Send me the beer
This guy has actually done the dyno for it http://www.carnut.com/ramblin/dyno.html He shows up to 40 hp lost. Here is another http://www.highperformancepontiac.co...o_testing.html They got 20 hp from a electric fan and water pump change Car Craft May 2000 showed a dramatic HP loss with various fans and clutches. Some up to 50 hp. All the above HP gains will be greatly reduced when the electric fan is running. But as we already know its runs far less than a stock fan and doesn't run at all on the highway. I know I get about 2 mpg better than when I had a stock fan on my stock 350. Thats barely measurable in a 60 ft run, but I usualy drive 30 miles at a time to work and it does add up to about one half gallon saved per trip @ $2.65/ gal. or one tank of gas per month. $45 less I have to pay each month. Last edited by dwcsr; 05-30-2010 at 01:27 AM. |
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#19 |
Account Suspended
Join Date: Jan 2007
Location: Tucson
Posts: 2,183
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Re: HP gain with electric fan and water pump
We have a WINNAH!
The dyno doesn't lie. Send me your address and I'll send the brewski's! |
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#20 | |
Cruzin
Join Date: Dec 2009
Location: on the road
Posts: 2,835
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Re: HP gain with electric fan and water pump
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Lime Wife's 67https://www.google.com/url?sa=t&rct=...wZEMODaS2d94u8 Back to the Fifties 59 https://www.google.com/url?sa=t&rct=...NAeStpydfrcj_U Proverbs 3:5,6 "Thanks to the Interstate Highway System, it is now possible to travel across the country from coast to coast without seeing anything."Charles Kuralt In memory of our first baby daughter, daddy and mommy love you. Danica Grace 6/26/14
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#21 | |
Registered User
Join Date: Jan 2007
Location: Whitehorse, Yukon, Canada
Posts: 166
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Re: HP gain with electric fan and water pump
Quote:
Hey thanks all you guys, think I'll keep it simple on break-in for start up.
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"gotta love something that works without a computer" Last edited by realsteelGM; 06-02-2010 at 09:28 AM. Reason: coarse reply |
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