Agreed..50/50 is the test and its validity and the interpretation of the data. I would maybe put a little % more on the interpretation of the data.

As an example and from my experience only. How much of the residual air that makes it through the radiator could actually help reduce some of the load that is put on the engine to turn the fan? Is it still at a speed such that it could aid in turning the fan?

My car runs 180* @ 70mph with no fans running but as soon as I flip the switch it cools to 160*.

Additionally, agreed, most SL6 guys rpm range is probably from idle to 3000rpm.

Even though, the hp loss at these RPMs (Idle to 3000) is less than at 4500 but remember this was with a 350hp engine. The engine probably didn't notice as much. I would think the "power demand" of a fixed fan and to a lesser extent a clutch fan would be greater (more noticeable) on a smaller engine making less HP.

Just thinking out loud.

I gotta tell you, I love threads like this. THIS is what the internet was invented for! Arguing the merits of fans!

Just last week the fan clutch in the truck decided to take a crap. By pure happenstance I noticed it. Lucky. I was 200+ miles from home and determined that it would flow enough to keep cool at highway speed, but overheat in traffic. But it was a strait shot home and I pretty much made it without stopping.

But....the mileage took a turn for the better. I wasn't able to fill up and generate a number, and I swapped in a new fan clutch when I got home. But judging by the gas gauge, I suspect I picked up 2 to 3 mpg. Power felt better too. As soon as I get some other projects out of the way, I'm putting electric fans on everything. The OEMs do it, why shouldn't we?

As to the arguement at hand, Dan makes some excellent points. I'm sure he's right in a general sense. But I gotta side with the other guy - as far as we know, it works on HIS car. If you think about it, we're dealing with low power engines so it stands to reason that a paltry few horses would make a noticeable, quantifiable difference. I buy it.

Just thinking about fans makes me all drooly to commit to doing the plug in hybrid idea (electric fan, power steering, water pump, no alternator). If that fan is sucking that much beans, imagine what improvements are lurking at the crank pulley.

Kip-on-Truckin'

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1965 Valiant wagon Turbo slant (work in progress)
2000 Chevy 155" cargo van - The Abductor
1970 Newport convertible
1996 Buick Roadmaster Wagon
1966 CruiseAire motor home
1990 Toyota 1 ton box truck TURBO slant (scraped)

Don't forget that the older cars have very low output alternators, and an electric fan may be too much current draw........................

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

I have found, over the years, that so much changes from tank of gas, to tank of gas, that it is really hard to draw conclusions from a single tank of gas. The A body tank has a nasty habit of trapping air on one corner or another, and you can get a gallon difference from tank to tank, depending on how the car sits at the station. At the least, you would have to fill at the same pump every time. And then, driving conditions change so much form week to week. It is just difficult. I have kept records on every tank of gas for 15 years, and am uncertain as to cause and effect of most changes. The one thing I can say is, that changing too many things, too quickly will really confuse the issue. I think you have to get 3 or 4 tanks under your belt before you can make any conclusions at all.

That being said, when I went to an electric fan, I noticed that I got an additional "easy" 500 RPMs out of a stock slant. It was groaning to get it to 4500 with the solid fan, and spun up to 5000 with the electric fan. I did not notice any significant increase in gas mileage. Although, I am not saying that is not possible. I just didn't notice it in my figures. As I have said many times, the things that got the biggest increase in mileage was improving the wiring, and going to a standard tranny with OD. Every other change represented just tiny, incremental improvements. That would be dual exhaust, a 2 bl carb, and electronic distributor, mostly.

I think the bigger improvement with an electric fan is that the engine warms up more quickly. If you drive short trips, that might get you better gas mileage. Like I say, there are so many variables, it is just hard to tell what does what. And was the gas the same? WAs the temperature the same? Were you at the same altitude? Was there a tail wind or a head wind?

My Dad kept mileage records on a cross country trip years ago. He drove all the way to the Rocky Mountains in a VW Microbus,(ugh). He got better mileage going East than going West. What is the conclusion here? Well, you could make up all kinds of things, and convince yourself it was right. But we thought then, and I still do, that he was seeing the difference in going prodiminantly uphill going West, and just the opposite coming East. The East Coast elevation is 200-300 feet above sea level, give or take a few hundred feet. And Denver is 5000 feet above sea level, give or take. He also drove up into the mountains. Sure, he was driving up and down hill in both directions, but the net was that he had to be going up hill more going West. Are there other explanations? Sure. And maybe we are wrong. It just illustrates the difficulty of drawing conclussions from only a single set of data, that being the number of gallons consumed in a given distance. It is important to nore here, that he did not draw these conclussions from any single tank of gas. He did not see this pattern until he was home, and graphed the gas mileage for the entire drip.

Sam

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I like an aluminum flex fan because it's a light weight item (easier on the pump bearing), and has no parts to wear out (I've seen some cheap ones with lossened rivits though)
And it works. Simple enough. Van runs great...although I don't have the scientific data to back up my opinion on that!!! Might run like dog squeeze for all I know!!!

I bought a later model alt with more output. Rated 75 amps. It covers all accessories. Lights, 4 rad fans, 1 trans fan and electric fuel pump.

I think people overestimate how much alternator is needed.

I have EFI, electric fan, Hella headlights, and MSD on my '68 Dart, and the 40 amp stock alternator was fine. I now have a 60 amp stock replacement, which is also of course totally fine.

The '64 Dart has EFI, Jacobs ign, and elec fan. Runs a 45 amp super mini alternator (Geo metro??) with no troubles. Yes, I can run my wipers, lights, radios/CDs, and heaters too.

If I had AC or other bells and whistles, I might upgrade the alt.

Just my 2 cents...

Lou

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Home of Slant6-powered fun machines since 1988

To clarify a few questions:

The figures I posted were based on filling up at the same station and same pump and same grade of gas at the same time of day, every two days. The rear of my car is much higher than the front so there is no entrapment of air in the tank. They were also based on 500 miles of driving the same route and average temperature. They were also done after new gaskets were installed on the manifolds and exhaust system were correctly sealed. Mileage was not taken before and after manifold gasket changes. They were taken after the work was done.

Yes, Kipamore hit on a key point. The engine warms up much quicker and runs more efficiently over a greater percentage of time. Like Sam pointed out I too can easily run the engine much higher rpms, and in a shorter distance. It used to quickly run up to 4000 rpm and stop with a 1920 Holley. Now I can easily hit 4500 in a heart beat.

The ProComp 16" fan only draws 10 amps, and rarely ever comes on at cruise even in 90 plus degree weather, unless your in stop and go traffic.
So it is only on at idle which and is not a huge load. During the fall, winter and spring I can drive to work and back with out ever having the fan come on. I do have a new stock radiator, heater core and about 2 years on a complete rebuild. When we acid cleaned the block we got 1 and 1/2 coffee cans of junk out of the block, so I know it is getting good circulation for max cooling.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Isn't this the reason for dash fires? Or is upgrading the alt. and not the wiring a myth for starting fires???

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Chris'
Autobody
Restoration
Service

Upgrading the alternator significantly without addressing the wiring to (and through) the ammeter is definitely a very, very risky thing to do. The myth is that an ammeter is a ticking time bomb waiting to burn your car down.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

UPgrading your wiring, and not the alternator, is the better choice over upgrading the alt, and not the wiring. Since you have to do the wiring anyway, do it first. Maybe that is all that is needed.

Sam

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Who deleted this post? I know it wasn't the original poster so fess up.

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Nope, not if you upgrade the wiring and use relays and breakers as I did.

I hadn't even noticed that it was missing. Only the original poster or a moderator can delete a post, but why would a moderator delete the original and leave my reply which quotes the original? Something's fishy.

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David Kight
'62 Valiant Signet, White
'98 Dodge Dakota
'06 Jeep Liberty

Growing older is unavoidable but growing up is strictly optional.

CONSPIRACY!!!!

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vm