HP gain with electric fan and water pump

[realsteelGM]

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.

[Beatcoaster]

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!

['72customdeluxe]

Even on a good meziere unit rebuilds are in short intervals for street usage, atleast on a daily driver. I would stick to mechanical

[realsteelGM]

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.

[Fitz]

Originally Posted by realsteelGM

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.

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.

[tqlspec]

Originally Posted by Fitz

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.

Fitz - I'm just curious where this information came from. The alternator puts X amount of load on the engine, as it is always "on." The engine is always loaded by the alternator. This would be true on new vehicles with load controllers. Just my 2 cw.

[Fitz]

Originally Posted by tqlspec

Fitz - I'm just curious where this information came from. The alternator puts X amount of load on the engine, as it is always "on." The engine is always loaded by the alternator. This would be true on new vehicles with load controllers. Just my 2 cw.

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!

[Tkmadone]

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!

['72customdeluxe]

People don't just convert to electric accessories for no reason. They make power

[Jacfourteen]

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.

[tqlspec]

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.

[Ackattack]

Originally Posted by Fitz

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!

That makes since to me, basically you can't get more power than you put in.

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

[Shyguy]

Originally Posted by Ackattack

That makes since to me, basically you can't get more power than you put in.

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

Well, I am not a nuclear mechanical engineer, but I worked with a lot over the years and it makes sense to me.

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

[dwcsr]

Originally Posted by Fitz

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!

While all this is technically accurate I think its miss applied. For the 3 minutes in maybe 10 minute intervals at idle or in traffic that the electric fan runs to cool the engine the above applies. Anything above 35 mph the air coming into the radiator cools the engine and the fan is not needed and free wheels saving up to 15 hp in most cases. If you have a mechanical fan pulling 5500 cfm it spins at full force at every rpm that the engine runs providing the engine doesn’t have a clutch fan. Most clutch fans spin longer than actually needed so they don’t free wheel prematurely and cause an over heating condition.
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

[mclairmo]

Originally Posted by realsteelGM

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.

Make sure the water pump pulley is smaller than the crank pulley so as to keep the water pump speed up enough at idle. Otherwise, you may have insufficient coolant speed at idle.

[Fitz]

Originally Posted by tqlspec

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.

If there is no clutch on the fan it represents a constant load so an electric fan running off a thermostatic switch is a lower engine load. If the electric fan is always on it's probably about the same load as a belt driven fan without a clutch. If the belt driven fan is on a clutch then there's probably little or no difference between it and an electric fan running on a thermostatic switch.

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!

[Fitz]

[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....

[dwcsr]

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.

[Fitz]

We have a WINNAH!

The dyno doesn't lie. Send me your address and I'll send the brewski's!

[Hubscrub]

Originally Posted by dwcsr

.

"I'm not a rocket scientist but I did stay at a Holliday Inn Express"

Sorry I couldn't resist

[realsteelGM]

Originally Posted by Fitz

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!

Hey maybe I'll just install aerodynamic solar panels on my roof, thus eliminating draw on the alternator and with enough speed it would fly!
Hey thanks all you guys, think I'll keep it simple on break-in for start up.