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Electric fan
https://www.slantsix.org/forum/viewtopic.php?t=61886		 Page 2 of 3
Author:  SlantSixDan [ Tue Jan 30, 2018 9:59 am ]
Post subject:  Re: Electric fan
Read this and this and this (entire threads).

You're not going to free up anything like 10 horsepower with an electric fan, and putting an electric fan on an old car without upgrading the electrical system is begging to get stranded and have to repair expensive and extensive damage, whether or not you sit at idle. If you do decide to put in an electric fan, do the whole job, do it correctly, if you like your car and want to keep it.
Author:  rich006 [ Tue Jan 30, 2018 10:26 am ]
Post subject:  Re: Electric fan
Quote:
I don't anticipate faster warmups since the thermostat opens based on the temp of the coolant in the block, not the radiator.
During warmup, while the thermostat is closed, the fan can still delay warmup by blowing cool air across the engine. Isn't that why some people put a piece of cardboard in front of the radiator in winter?
Author:  Reed [ Tue Jan 30, 2018 10:48 am ]
Post subject:  Re: Electric fan
Quote:
Quote:
I don't anticipate faster warmups since the thermostat opens based on the temp of the coolant in the block, not the radiator.
During warmup, while the thermostat is closed, the fan can still delay warmup by blowing cool air across the engine. Isn't that why some people put a piece of cardboard in front of the radiator in winter?
Having grown up in an area where cardboard across the radiator wwas common when the temperature was subzero Fahrenheit for large portions of the year, I don't think the presence or lack of a radiator fan was the determining factory in engine warmup times. Ambient temperture and the starting temperature of the coolant and cast iron engine blocks were. Once the engine had warmed up and coolant was flowing, the ambient temperature was more than enough to keep the coolant flowing through the radiator cooled without additional airflow across the radiator.

I still don't buy the argument that the fan delays warming the engine by blowing cold air across it. That is like saying the exhaust manifold speeds the heating of the engine because it radiates heat next to the block. The engine heats from the inside out and the small amount of air moved by the fan is not enough to affect the heating of a large lump of iron like an engine block. The radiator is a much more efficient heat exchanger than is the engine block, which is why the air pulled by the fan can cool the liquid in the radiator.

Back to your cardboard question, cardboard is usually used when there is a problem with the cooling/heating system such as a stuck or incorrect thermostat. It is a bandaid not a standard operating procedure. I lived through numerous winters where it would take 30 minutes for a car to really warm up (yes, even cars with electric fans sitting still in the driveway). It takes the same time for a car engine to warm up with a mechanical or electric fan and with or without cardboard. The issue is burning enough fuel to create enough BTUs to heat the engine block and coolant when the block and coolant are in a super-cooled state due to the ambient temperature.

When my grandfather died, I inherited a 1978 Mercury Zephyr station wagon that had been ordered new by his brother. It as ordered for delivery to Alaska and was equipped with the "northern cooling package" which basically meant it had a mechanical two bladed fan. Why only two blades? Because the ambient temperatures were low enough that it needed less air to flow across the radiator to cool it. Did it get any better performance or economy than a same-year Zephyr with a more standard four blade mechanical fan- no. My brother had a 78 Ford Fairmont wagon (same as the Zephyr) and economy and performance differences between the two were negligible.
Author:  62 alum [ Tue Jan 30, 2018 1:17 pm ]
Post subject:  Re: Electric fan
My 66 valiant has an electric pusher fan off of a older Mercedes. Having stock wiring and alternator I run the fan and headlights off the battery/ alternator circuit thru relays.
Have ran it two summers without problems.
One point in favor of the electric fan is that if you are old and clumsy you will not destroy timing lights.
Please do not ask me how I know.
Author:  SlantSixDan [ Tue Jan 30, 2018 2:06 pm ]
Post subject:  Re: Electric fan
Quote:
During warmup, while the thermostat is closed, the fan can still delay warmup by blowing cool air across the engine.
This is not correct. Never has been, no matter how often it's repeated.
Quote:
Isn't that why some people put a piece of cardboard in front of the radiator in winter?
No, they do that because they can't be bothered fixing the car correctly by putting a correct-temperature, working thermostat in.
Author:  tophat [ Tue Jan 30, 2018 5:23 pm ]
Post subject:  Re: Electric fan
Quote:
None of my 4-blade slant six fans ever failed. My road racing '66 Dart spun 5800 RPM repeatedly with the "death fan".
Here is the link to my original post about the 4 blade fan coming apart. Thanks to photobucket, the post is now close to useless. I am in the middle of moving, I know the remains of the fan are somewhere in the 40x40 building I have yet to move. I will post new pictures once it is found.
http://www.slantsix.org/forum/viewtopic ... &hilit=fan
Quote:
My 66 valiant has an electric pusher fan off of a older Mercedes. Having stock wiring and alternator I run the fan and headlights off the battery/ alternator circuit thru relays.
Have ran it two summers without problems.
One point in favor of the electric fan is that if you are old and clumsy you will not destroy timing lights.
Please do not ask me how I know.
Good point, especially with expensive timing lights.
Quote:
I debate how much energy is actually wasted with a fixed fan. The energy draw for a fixed fan will be highest when the vehicle is stationary, but that is exactly when you need the fan to be working. Once the vehicle is moving the fan takes less energy to turn because it is not pulling the air across it. The air is already moving across it thereby reducing drag. Those dyno tests you see where fixed fans are compared to clutch and electric and no fans are really deceiving and not accurate. If they were accurate they would be performed with at least a radiator in front of the engine and a fan blowing air at 40-60 MPH.
Good point. Here is one dyno test I found where they used a "radiator simulator" but no fan blowing 40-60 mph air.
http://www.carnut.com/ramblin/dyno.html

Thanks DadTruck for the mid 90's caravan suggestion. I still have a few fans around somewhere from brand x cars that I scrapped in the past, but the next time I head out to the junkyard I will keep my eyes out.
Author:  dude0936 [ Tue Jan 30, 2018 6:21 pm ]
Post subject:  Re: Electric fan
I have the opportunity to operate a Mustang chassis dyno at my employer (Pennsylvania College of Technology). We have a 1967 Dodge Dart GT with a slant six. We have a dyno class that has run twice a year for the last five years, and we have performed about 45 tests per class. Among the tests are the installation of the Super Six setup and an electric fan. We do all our testing in an ABA style, which means we baseline the Dart. To do this we make three consecutive runs that are within 1% of each other. We then add the test component to the Dart and reevaluate the performance with three more consecutive runs within 1% of each other. Lastly, we remove the component and again perform three more runs. If the first three runs (pre-test) and the last three runs (post-test) are the same, the performance increase or loss of the middle three tests is valid.

The Super Six setup (Carter BBD 2bbl, intake and exhaust manifold) takes the place of the 1920 Holley, intake and exhaust manifold. In both cases the carburetors are well sorted out and perform well. The averaged performance increase from the 10 classes for the Super Six setup are:

Peak Torque: +0.387 lb/ft
Average Torque: +1.107 lb/ft
Peak Horsepower: +4.704 hp
Average Horsepower: +4.389 hp

The replacement of the fixed four-blade fan with a 16” electric (pusher) fan results in the following:

Peak Torque: +2.457 lb/ft
Average Torque: +2.997 lb/ft
Peak Horsepower: +2.324 hp
Average Horsepower: +2.582 hp

When the electric fan is added, we also add a 1995 Cummins Turbo Diesel to cover the additional amperage demands of the fan. The wiring harness has been substantially upgraded to work with the fan and the high-amp alternator.

All the numbers above are rear wheel horsepower (RWHP).

Chris
Author:  Reed [ Tue Jan 30, 2018 8:03 pm ]
Post subject:  Re: Electric fan
Chris- when you tested the fixed blade fan were you blowing air at the front of the car? Also, what RPM range were you testing?
Author:  dude0936 [ Tue Jan 30, 2018 8:20 pm ]
Post subject:  Re: Electric fan
Reed,

The fan we use to move the air is a 6.5' diameter fan, and it is used for ALL testing. I do not know the CFM rating of the fan off the top of my head, but it provides a maximum wind speed of 28 mph. The rpm most runs with the one- and two-bbls carbs tends to be from about 2200 rpm to 4200 rpm. When we put on the four-bbl carb, we can extend the rpm 5000 rpm or more. The objective is to try to sample the data at 200 rpm/s to 500 rpm/s. The 2200-4200 rpm pull would last a maximum of 10 seconds. We shoot for 8-15 second pulls. Anything shorter than 8 seconds has too many variables that can sway the results. Anything longer than 15 is a stress test, and it makes it harder to repeat the pull without a substantial wait time due to the increased heat.

Chris
Author:  Reed [ Tue Jan 30, 2018 8:50 pm ]
Post subject:  Re: Electric fan
Interesting. Thanks for the info!
Author:  SlantSixDan [ Wed Jan 31, 2018 4:37 am ]
Post subject:  Re: Electric fan
Quote:
The replacement of the fixed four-blade fan with a 16” electric (pusher) fan results in the following:

Peak Torque: +2.457 lb/ft
Average Torque: +2.997 lb/ft
Peak Horsepower: +2.324 hp
Average Horsepower: +2.582 hp
This comports well with the data presented here. At what RPM were these gains found?
Quote:
When the electric fan is added, we also add a 1995 Cummins Turbo Diesel to cover the additional amperage demands of the fan. The wiring harness has been substantially upgraded to work with the fan and the high-amp alternator.
Wise. In other words…the complete job, done correctly. :-)
Author:  Charrlie_S [ Wed Jan 31, 2018 4:44 am ]
Post subject:  Re: Electric fan
Note, the electric fan gives a greater torque increase, then the super six conversion. But the super six, has a greater HP gain.
Author:  dude0936 [ Wed Jan 31, 2018 4:45 am ]
Post subject:  Re: Electric fan
Peak Torque: +2.457 lb/ft at 2700 rpm
Average Torque: +2.997 lb/ft from 2200-4200 rpm (average torque increase through the entire pull)
Peak Horsepower: +2.324 hp at 3600 rpm
Average Horsepower: +2.582 hp from 2200-4200 rpm (average horsepower increase through the entire pull)
Author:  SlantSixDan [ Wed Jan 31, 2018 4:50 am ]
Post subject:  Re: Electric fan
Quote:
Quote:
I did the electric fan upgrade on my 63 Dart after the 4 blade "death fan" exploded. My 81 D150 came in to my possession with a dreaded 4 blade death fan.
None of my 4-blade slant six fans ever failed. My road racing '66 Dart spun 5800 RPM repeatedly with the "death fan".
Josh is right. I'm sure the fan failure on the Dart was a very loud, very frightening event, Tophat, and it's understandable why you'd react badly to that experience, but this "dreaded death fan" business of yours is unrealistic and inappropriate; you're trying to gin up a lurking menace where there isn't one.

Did your fan fail? Yep, I believe you. Do these fans have a tendency to fail, a track record, a history? Nope! As engine fans go, they're one of the least failure-prone designs. Fact is, when you drive an old car you're at elevated likelihood to experience a very unusual failure sooner or later, one that wouldn't occur to most drivers because it almost never happens. Driveshafts have failed spectacularly when U-joints let go, yet we don't call them "the dreaded death-driveshaft". Connecting rods have blown great big holes in the sides of engine blocks, but we don't tell ghost stories about "the dreaded death-connecting rods". There are Ford engines notorious for spark plug hole threads letting go, then the plug is launched like a missile—hard enough to dent the hood from the inside—and yet we don't hear talk of "the dreaded death-spark plugs".

There were Fords with notoriously failure-prone engine fans in the 1970s. People died, and Ford did what they do best when they screw up like this (stare at the sky, say "tut tut, looks like rain", drag their feet and refuse to cooperate with governmental safety investigations, etc). Those fans were nothing like the ones you're trying to make people afraid of, so please knock it off, thanks.

Fact is, it has always, always, always been good practice to never, ever, ever stand in line with a spinning engine fan, no matter what kind it is. This is on the same list as "never smoke while filling the gas tank or working on the carburetor", "make the last jumper cable connection on the engine block, not the battery", "wear your seatbelt", and other simple, basic, sensible safety precautions.
Author:  SlantSixDan [ Wed Jan 31, 2018 4:51 am ]
Post subject:  Re: Electric fan
Quote:
Note, the electric fan gives a greater torque increase, then the super six conversion. But the super six, has a greater HP gain.
This does not surprise me. The main improvement from a good 2bbl swap isn't moar horsepowerz, it's better driveability (which makes the car feel like it's gained a whole lot more torque and HP than the numbers show).
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