I'm running one from Tuff Stuff.
Electric or not?
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goldduster318
Overzealous Car Modifier
The Contour Fan and 26" 3 row champion radiator has now done the Woodward Dream Cruise in 85-90 degree weather about 10x and now the entire power tour long haul without getting hot whatsoever. I can cool the car down by forcing the high speed on.
I was just driving around yesterday (89 degrees + humid) with the A/C blasting, sending 40 degree air out of the vents, the car was running perfectly cool even with only the low speed on.
The Delco 12SI 78 Amp alternator, 6 GA charging wire and clearly an amp gauge bypass is all you need. I also have EFI with an electric fuel pump.
I was just driving around yesterday (89 degrees + humid) with the A/C blasting, sending 40 degree air out of the vents, the car was running perfectly cool even with only the low speed on.
The Delco 12SI 78 Amp alternator, 6 GA charging wire and clearly an amp gauge bypass is all you need. I also have EFI with an electric fuel pump.
BT67Dart
Well-Known Member
Do you have a part number for the fan and shroud setup? Might keep this in mind for my build.
goldduster318
Overzealous Car Modifier
Mine is an original Ford one. Just look up a 1999 Ford Contour with a 2.5 V6.
BT67Dart
Well-Known Member
I'll check it out, thanks for the info.
mopowers
Well-Known Member
How many amps does a Contour fan draw on high?
goldduster318
Overzealous Car Modifier
Just went out, zero'd the meter, hit the force on high speed switch and read it with my amp clamp. This is the total current draw on the car but it is the only thing that's actually on.
Just call it 20 Amps. It could be slightly more with the hood shut due to more restriction.
BT67Dart
Well-Known Member
I see that its a dual fan setup with a shroud. Did you attach that to a mopar specific radiator or do something different? Maybe you can share a few pics/details of your setup when you have time. I had an electric fan setup on a 68 Barracuda years ago, but it was marginal on hot days. It was a pusher style (Spal dual fan) due to space limitations. Maybe there are better options now that a few years have gone by....
mopowers
Well-Known Member
Thank you! I would've guessed those would've been higher. That's good to know.
goldduster318
Overzealous Car Modifier
Older pictures but I just used some aluminum bar stock. It's important to note this is a 26" radiator and most cars will have 22" unless its 73+
This was a radiator that at least used to be sold for a B-body but was short enough to fit in an A-body. The radiator is 12 years old so I haven't looked into anything in some time.
This was a radiator that at least used to be sold for a B-body but was short enough to fit in an A-body. The radiator is 12 years old so I haven't looked into anything in some time.
BT67Dart
Well-Known Member
Thanks for posting the pics and details. I have a 67 Dart, likely it has a 22 inch wide opening for the radiator. Did you remove metal from the radiator support area to maximize air flow for the 26 inch wide radiator? I know for the barracuda, I had only 22 inches width, might be why your setup is cooling better than mine years ago.
goldduster318
Overzealous Car Modifier
I didn't cut the opening larger whatsoever. It has the 22" opening.
BT67Dart
Well-Known Member
Thanks for the idea, I'll check into that when I am ready.
goldduster318
Overzealous Car Modifier
Its likely yours didn't cool as well for multiple reasons. Pusher not puller, lower capacity fan, lower capacity radiator. This absolutely does not restrict the radiator air flow (this car has NO fan running whatsoever above 40 mph -> it's turned off in the ECU now). The shroud also covers the entire radiator short of about 1.5" at the very bottom and the edges you see. It's a downflow radiator as is stock.
I also have a 6-speed stick so there is no transmission heat but I have A/C...and plenty of additional capacity.
Some of it is how efficient the car runs -> this thing is scienced out. EFI, plenty of ignition timing, and it has aluminum heads. I got 19 mpg average on Power Tour and 21 mpg on the way there going 75 mph. Usually I get about 16 mpg if I'm not standing on it. The entire car is a "system" that needs to work together. 180 thermostat.
I also have a 6-speed stick so there is no transmission heat but I have A/C...and plenty of additional capacity.
Some of it is how efficient the car runs -> this thing is scienced out. EFI, plenty of ignition timing, and it has aluminum heads. I got 19 mpg average on Power Tour and 21 mpg on the way there going 75 mph. Usually I get about 16 mpg if I'm not standing on it. The entire car is a "system" that needs to work together. 180 thermostat.
BT67Dart
Well-Known Member
I agree with your comments. Pusher fan was not the greatest but I had no space for a mechanical fan setup. I did work, but no room for error. I have made no decision on transmission at this time, car came with a 727, might just use it. Aluminum heads are what I have planned for the 340, if the block is usable. Also looking at EFI vs carb. Might follow up with you when I get closer to making build decisions. Sounds like you have a nice setup. Congrats on your car!
HankRearden
Well-Known Member
I'm a fan of only running electric fans when you have a race car or no other option.
Not worth dumbing around on a street car.
Most of these old mopars that are street cars only have colling issues due to a crap radiator or poor tuning.
I've seen guys run a 500 stroker at optimal temps with a factory clutch fan,shroud and a good radiator.
Don't forget the slight hp loss from the mechanical fan will now in part become hp loss from the alternator working harder.
Especially if it is one of the old anemic factory mopar alternators.
Not worth dumbing around on a street car.
Most of these old mopars that are street cars only have colling issues due to a crap radiator or poor tuning.
I've seen guys run a 500 stroker at optimal temps with a factory clutch fan,shroud and a good radiator.
Don't forget the slight hp loss from the mechanical fan will now in part become hp loss from the alternator working harder.
Especially if it is one of the old anemic factory mopar alternators.
goldduster318
Overzealous Car Modifier
By all means run a mechanical fan if it suits you, what you are trying to do, etc. They certainly work for cooling. I still run the OE Clutch fan on my Chevy Colorado because there has never been any reason to mess with it. Agree completely that the radiator and the tuning are a huge part.
You will always gain HP with an electric fan, even if it ran constantly. The old fan dyno article shows that. Anyone with an electric fan could theoretically have it turned off during WOT where it is drawing 0 HP (I can do it my case due to having an ECU but there are other ways to do it). But just for kicks, lets use my Contour fan that has 2 motors and do a theoretical calculation:
20 amps draw at 14V = 280 Watts. There are 745.7 watts per HP -> 280/745.7= 0.375 hp. Let's just say the alternator isn't very efficient and has a 50% efficiency. 0.375/.5=0.751 hp. Then lets say the pulleys have a 3:1 ratio -> so at the crank the load will be 3x as much => 2.25 hp.
There is no mechanical fan on earth that only draws 2.25 hp and can cool the car. This is why you see electric fans even in full size trucks these days.
I would not recommend anyone run the stock alternator or the stock charging wiring and an electric fan.
The big thing that turns people off to electric fans is that the difference between the cheap zip tie to the radiator ones with horrible motors and fan designs and a fully engineered system with a properly designed shroud is huge. Most of the setups sold by the lower end aftermarket radiator companies are also straight garbage.
Found the car craft info from their fan dyno, as you can see my calculation above was pretty realistic:
Car Craft, May 2000, p50-51. Fan dyno test.
No fan 496hp
Black Magic fan, running 494hp
plastic fan 460hp
flex fan 466hp
hi-perf flex fan 476hp
6-blade rigid fan 449hp
non-thermal clutch fan 485hp
4-blade rigid fan 473hp
HD thermal clutch fan 476hp
thermal clutch fan 487hp
goldduster318
Overzealous Car Modifier
Frankly another thing to note is a mechanical fan is directly related to engine RPM, so it moves less air at idle where the electric fan is basically one speed continuously so long as it's not a 2 speed fan.
While I don't doubt the test results something that gets overlooked is if the fan is pushing air at 60 mph and the air going through the radiator is going 60 mph (driving 70 on the interstate) the fan is not causing any HP loss. It's an object in motion it tends to stay on motion. And the air moving past it is the same speed or higher than the fan can push so no load on the fan blades they are simply cutting the air not pushing it.
If the air was traveling at 120 mph past the fan it could even generate a bit of HP ( but most likely negligible) and yes under those conditions the electric would be powered off so no additional load on the alternator.
I'm not against electric just as mentioned the not properly engineered ones. Same goes for mechanical too.
goldduster318
Overzealous Car Modifier
I doubt the air speed through the radiator itself as a result of the fan is very high, to me even 30 mph seems high at any rpm. The cooling fins are quite restrictive and usually the mechanical fan shrouds have a lot of clearance due to engine rotation. Air being a compressible fluid, a lot of the air being forced through will be able to travel around it somewhat. I would have to actually set up a camera to see if the electric fans even pinwheel at freeway speed when they are free, I somewhat doubt it but I am not 100% sure.
The losses might be reduced somewhat but its completely dependent also on engine RPM. That test was done with more RPM due to the HP numbers. Likely a lot more dependent on engine RPM than road speed. You care less about HP numbers at low engine speeds when it has the least effect. You also have the underhood being a high pressure area relative to the surrounding environment which would reduce airflow.
The fan is still causing loss because its high drag due to its 3D shape. This is the principle the fan clutch would work on, it allows some slip so if its thermostatically cool it will slip a lot and the drag in the radial direction is slowing its rotation down. You can actually see this in the clutch fan vs fixed fan results. These fans are big so they have a pretty large moment arm on them. The drag formulas are highly dependent on frontal area and also the velocity (engine RPM and blade radius). Nevermind the rotating weight that's being added.
You wouldn't run a mechanical fan to maximize power, that I am sure of. If you want to run one because its what you're comfortable setting up, your budget, or whatever, sure.
That's the steady state draw correct? The initial hit when you throw the switch is likely much higher than that. Very short lived, but if you've got other stuff running the initial start up amperage can be an issue depending on the alternator.
This is 100% false.
The spinning fan still has drag. The blades are spinning perpendicular to the incoming air, and if anything the higher speed creates MORE drag on the fan blades.
No sir. That's not how that works at all. You're thinking the incoming air would spin the fan blades and provide power to the engine? Nope. The engine is spinning the fan, the fan blades are trying to act on the incoming air. All fans are designed to work at a certain RPM and air speed, outside of that range the drag created increases rapidly. And there's a maximum number for air speed with fan blades, after which they're just no longer effective regardless of design.
Needless to say, the mechanical fan blades on these cars are NOT designed to be a truly high speed affair, and they will certainly create more and more drag as the speeds increase. Not the other way around.
Exactly.
I'm curious about the initial draw when the fans kick on as well. I am currently in the middle of converting mine to this setup as mine would not stay cool on hot days with the A/C on at idle with the mechanical fan. I did try most everything I could before deciding to change over. This is an area where electric fans should shine, maximum speed is available even at idle, something no mechanical fan, clutched or not can do, which will help not only with airflow through the radiator but also help to push hot air out of the engine compartment in my opinion.
This guy did a pretty in depth video about using these fans, testing amp draw, air flow etc. It's not a perfect test as he doesn't test with it in the car and a radiator in front of the fans, but pretty informative if long. Actual pertinent information starts at approximately 8:45 minutes in.
goldduster318
Overzealous Car Modifier
There it is with the max hold on high. 65.2 -> now my fuse is 60A. You have to remember a few things -> In-rush current can be more than the fuse size, and is a lot higher than running amps, its not super relevant to system design other than wire size. 10 ga wire is fine for this purpose. You are in the 20's in an extremely short time, like 1 second or so.
I didn't watch that entire video but that test method doesn't seem too great. the fan CFM without a radiator is a bit irrelevant. I also didn't get the point about having an aftermarket and an OEM one.
Thanks for checking that, that's a bit higher than I was expecting honestly, although I do realize it's only momentary load.
I also agree about the test method in the video, definitely not real world scenario. I would have much rather seen him do at least some testing with it in the car, or at least bolted to the radiator. Just thought it did provide some useful information despite that.
I also agree about the test method in the video, definitely not real world scenario. I would have much rather seen him do at least some testing with it in the car, or at least bolted to the radiator. Just thought it did provide some useful information despite that.
This is something to always consider when comparing CFM ratings on fans. There really isn't a required standard across the board, so you don't know if the fans you're comparing were tested in equivalent scenarios. That's especially true if you're comparing different brands, or aftermarket vs OEM. While I would not say that OEM all perform the same test, I would wager its much more likely that an OEM rating was done on the car for it's given application or on a representative bench, where with aftermarket I would actually bet that's a free air CFM rating and likely higher than what you're actually gonna see in the real world. Or possibly some kind of test bench set up, but not necessarily representative of what you may be using it for because they're generic.
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