73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Performance => Topic started by: rich weyand on February 22, 2014, 06:54:04 pm
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I have been researching going the electric fan route. The engine has a heck of a time warming up in the winter. Most people don't know, but the thermostat never shuts off completely. There is a bypass hole that lets some water flow all the time. The water going into the engine from the radiator in the winter is stone cold. Cold engines don't run as well, and get worse gas mileage.
Of course, the other issues apply as well. I prefer not having the shroud and fan and all, both because it makes the engine harder and more dangerous to work on and because it's not as pretty as having it gone. Not running the mechanical fan all the time saves gas mileage, frees up some power and torque, and takes a load off the water pump bearings. It also keeps water and such that gets splashed into the radiator from getting distributed all over the engine and engine compartment.
After much poking around, I went with a pusher, no shroud. Yes, yes, I know, but I don't tow, I don't plow, I don't go rock crawling, and I don't drive in the mountains or the desert. I don't even sit in stop and go traffic. Mostly I'm moving, and you don't need any fan when you have ram air through the radiator.
I selected the Flex-a-lite 398, and flipped the blade over for pusher mode. This fan is 16", which fills the core hole in the bulkhead top to bottom. It delivers a real 2500 cfm (read reviews carefully; there are some fans out there that, um, over-spec, shall we say). I used the Flex-a-lite 31149 adjustable fan controller. I figured if either blows up, I can tell them, hey, the fan and the controller are both yours; what gives? Both the fan and controller are on sale at Amazon.
Here's the fan install. I bolted a couple of 16" long pieces of 1" aluminum L-channel (1/8" web) to the vertical struts on either side of the radiator opening using existing holes, creating a mounting flange. I then bolted a couple of 30-1/2" pieces of the same material across, at the right distance for the fan mounting holes. I used 1/4"-20 x 3" pan-head machine screws bolted through the fan mounting holes, then used a nut on either side of the crossbar pieces so I could hold the fan back toward the radiator.
To get the shroud off, I pulled the upper half up at the seam and slid a hacksaw blade in between the pieces to cut through the staples. The fan is so big, the hood latch and the vertical brace that runs down from the hood latch have to come out to get the fan in. Once everything is fitted, the assembly order is: mount side flanges, mount fan to upper crosspiece, mount bolts on fan for lower crosspiece but do not mount lower crosspiece, mount upper crosspiece and fan between the side flanges, re-install hood latch and vertical brace, slide lower crosspiece behind vertical brace, mount to side flanges, and mount to fan.
I really like how clean the engine compartment came out, and the fan install came out clean as well. Now to clean up the engine and engine compartment from all the thrown spray and see how clean they stay. Also be interesting to see what my mileage does.
In minor testing tonight, the engine came up to temp, and opened the thermostat (it didn't before). The fan turned on and cycled to maintain temperature. It is on for only about ten seconds, then off for almost a minute.
(http://users.rcn.com/weyand/smalls/imag0431small.jpg)
(http://users.rcn.com/weyand/smalls/imag0430small.jpg)
(http://users.rcn.com/weyand/smalls/imag0427small.jpg)
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Nice work, now you got all kinds of room behind your radiator.
I have found over the 30+ years of dealing with fluid pumps, mostly water, that 10 - 20 seconds on and 45 - 60 seconds off works real well, ( some have bladder tanks some do not ) for the electric motors. I have some that have lasted 15+ years before wearing out.
So I would guess your electric fan should be around for awhile.
Make sure to post follow up real world cases so we can see how it does.
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Does it also come with the wiring, and if not is it hard to make a wiring harness yourself?
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The fan controller comes with all the wires (including some really nice fine-stranded 10 AWG) and the crimp connectors, including the crimp spade females for connecting to the controller, the crimp eyes for connecting to the battery terminals and even the crimp splices for the supplied wiring to the fan pigtail. No extra parts required at all on the electrical side, with one exception. They give you 20A, 25A, and 30A fuses, but it is an 18A fan. The startup surge could be twice that, and the controller says it is good for a 40A startup surge, so, after I flash-bulbed the 25A fuse on first trial, I put in a 40A, which was not supplied with the controller kit. You may also need to put adapters on a side-terminal battery. You know, the kind that has a connection point on the back side of the hold-down bolt. Something that draw this many amps should be connected to the battery for best results.
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Hey Rich, just a curiosity question on my part, have you contacted them and asked why the controller is rated for a 40A fuse for start up and they only sent you the 3 fuses ?
The manufacture I work with on my regular job, has what they call a IQR ( internal question review ) where the dealers can send in this form when they run across things that need to be changed or machines that are made and don't work for the situation you are putting it in. Many other reasons, not trying to write a book.
My main point is over the 25+ years working with them, I have submitted a ton of these and have gotten a lot of things fixed or changed.
Maybe a few customers need to tell Flex-a-lite that they have overlooked the fact that it needs a 40A fuse, who knows, maybe they will just start sending the one right fuse instead of 3 wrong ones.
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Hey Rich, just a curiosity question on my part, have you contacted them and asked why the controller is rated for a 40A fuse for start up and they only sent you the 3 fuses ?
The manufacture I work with on my regular job, has what they call a IQR ( internal question review ) where the dealers can send in this form when they run across things that need to be changed or machines that are made and don't work for the situation you are putting it in. Many other reasons, not trying to write a book.
My main point is over the 25+ years working with them, I have submitted a ton of these and have gotten a lot of things fixed or changed.
Maybe a few customers need to tell Flex-a-lite that they have overlooked the fact that it needs a 40A fuse, who knows, maybe they will just start sending the one right fuse instead of 3 wrong ones.
I'll send them a note. I'm also not impressed with the female spade crimp terminals. Heavy plastic, not so much metal. Replaced 'em.
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thanks rich, but i got another question. how much does the fan draw from the battery in amps and are you having issues running it and the alternator not being able to keep the battery charged? Are you just running a alternator in the 60-80 amp range or do you have a high output alternator in the 140 amp area.
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I have a 55 amp alternator, new a couple years back. The fan is specced at 17.5 amps or thereabouts, and the startup draw is higher -- high enough to flash-bulb a 25 amp fuse. When the fan kicks on while idling, the engine does not slow down or anything like that. I have noticed no issues at all related to current draw. I do have a recent 78-series battery with 795 CCA @ 0*F, so that can punch out whatever it needs until the alternator catches up. Haven't tried with the lights on, though, and wasn't watching the voltmeter in my testing so far. Both of those might be interesting. Going to be cold here for a while, though, so I don't know that I can get it to kick on for a while and try those.
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First driving impressions. Spool up from idle is definitely quicker, such as when starting from a stop. Throttle response is improved, especially at low rpms. Kick-down shift is smoother and quicker to spool up. These changes are easily noticeable. Engine warms up quicker, and runs generally a bit warmer, since it is about 35 here today and the engine didn't previously come fully up to temp at this outside temp.
I had one tank that I sucked dry, so I filled it and will suck it dry and see what kind of mileage I get..
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Electric motors have start (inrush current) and running current. The controller is rated for 25-30% over the max inrush current to keep the heat dissapation down.
The inrush current is likely between 28A & 33A which, as you discovered, exceeds 25A. Not sure what the actual run current is but I bet it's more than 18A.
Here's an article on choosing fuses.
http://www.bdfuses.com/derating.php (http://www.bdfuses.com/derating.php)
From orbit via Android.
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Hey Rich, going to bug you with another curiosity question. I just went flex-a-lite web site and checked out the controller. I noticed it has a switch on the module for -/+ and norm on the controller. I did not find a temp range at all for the probe, have you ran any test to see at what temp the fan comes on ?
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Hey, bake74:
That's not a switch, it's a rotatey knob. I think it adjusts the spring tension against which the fluid in the probe and tube work. I adjusted it to about the middle so it would come on at 195 at the probe location. I used the lower passenger side of the radiator for the probe location (you can see the little black boot on the nose of the probe in the pic above) because you want to control the temp of the water into the engine. That's what the engine sees and that's what the whole cooling system is for. Since the engine is happy until 195 keeping the thermostat closed, that's what I set it at. It takes it down to 185 in 12 seconds, then the fan shuts off (10* below setpoint).
hatzie:
On the motor startup current: A motor generates back emf when it is spinning. It is a generator, too, and the back emf it generates fights the applied voltage and reduces the current. When the motor is stopped, there is no back emf, and the current flowing into the motor is the applied voltage through the resistance of the motor. This value is higher than the running current, and is called the locked-rotor current. How much higher depends on the motor design. If you want to know the locked rotor current, you can just measure the ohms of the motor sitting still, and divide it into the applied voltage. The motor resistance of this motor is probably about half an ohm, which would give a 30-amp locked rotor current.
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Given as cold as it has been here, the engine still does not warm up to temp while driving even with no fan (electric fan off), what with all the ram air through the radiator.
I fixed that with a $20 fender apron from Classic Parts. 3 pieces of double-sided tape to hold it to the fender crossmember in front of the hood latches, and a couple zip ties through the grill.
The engine now gets up to temp and turns on the fan intermittently even when driving along at an outside temp of 30*.
(http://users.rcn.com/weyand/smalls/imag0435small.jpg)
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Just a status report. Five months along, and no problems at all with the above setup. Even at 90 degrees, the fan won't come on except when sitting idling, and after I shut the engine off. I connected it to battery, so with the ignition off, as the heat soaks in the radiator, the fan will usually come on for 10 seconds after I stop.
I did switch from a 55-amp 10SI to a 94-amp 12-SI alternator. The fan, the subwoofer amp, the aftermarket headlights, fog lamps -- it all adds up, and my voltage was sagging at idle.
Gas mileage is 10ish around town and above 12 on the highway with 350/TH350/NP203/3.73:1 on 31" BFGs with the hubs FREE and the NP203 in HI (unlocked). That's with an Edelbrock 1406, air-gap manifold and 12-300-4 marine cam.
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awesome write up i am planning on this exact setup for my 79 K10
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I love this idea!
But i'm unsure if I can get the fan in the same spot with the AC unit in front of the radiator, not sure I'd have room for the fan in front of both behind the grille?
So my other question is putting the fan on the "mechanical" fan side, I know it doesn't clear up the area like what you did, but as far as the rest of the install you talked about, with the aluminum pieces, would be about the same? And would I still want to use the shroud to help cool?
I'm going to be running a serpentine system and because I'm a slight idiot (mostly because I know less than what I think I do) this system does not support a mechanical fan, though I already bought the fan and spacer :o
I will post a picture of the engine with the setup (without the fan on it) and don't laugh too hard, but could I still run the mechanical fan on this setup off that water pump pulley??
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How much clearance do you need for the AC unit? I can go measure and see if there's enough room to space the fan out.
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It looks like I have about 1-5/8" maybe a little more between where the ac unit and that front brace is.
And I do I need to change to an electric fan, it just looks bad the other way I was thinking, and I would need to get longer bolts, and I just don't think that it would be very safe!
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Not enough room for a fan in front then.
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I suppose that's ok, I kind of like the way the shroud looks in there =)
Do you recommend any good 17" single electric fans over the others?
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The only one I have any experience with is the Flexalite 16", which fills the radiator area top to bottom.
It moves a LOT of air.
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I have an ac truck that I added a couple pusher electric fans too. I had to trim them a little to get them to fit but they work great. May not be what your looking for but heres my setup.
(http://i493.photobucket.com/albums/rr299/69byrd/5DA36A12-1FBB-4FB8-B43C-0072B62E2DAD-589-0000008740E32A2F_zpsb824e132.jpg) (http://s493.photobucket.com/user/69byrd/media/5DA36A12-1FBB-4FB8-B43C-0072B62E2DAD-589-0000008740E32A2F_zpsb824e132.jpg.html)
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that is a good setup, I might as well get a new radiator now too. Prolly for the best considering the upgrades on the engine. What brand is that? And that clears the brace behind grille with AC?!
Is that setup preferred or how the electric fans need to be installed? towards the front of the vehicle? It appears the ones that I'm looking at are on the engine side...
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I'm thinking maybe this will be a good setup..??
http://www.summitracing.com/parts/gri-cu-70008
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The best setup will always be shrouded pullers on the engine side. That said, the 350s run cool anyway, so it isn't a problem unless you are towing in the mountains or plowing or something like that. A pusher in the front works fine for normal-duty applications
The twin fan setup has the advantage of being thin in the middle where the brace is, so I think that's the way to go for you. The single fan setup has the thickest part in the middle, the motor, and there just isn't clearance behind that brace for that and the AC cooler.
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I have two fans on the inside of the radiator with a shroud pulling air in. They are hooked up on an adjustable switch that triggers them to come on at whatever temp you set it on. I added the two on the outside for when I go to these rod runs where I sit in stop and g traffic for three to four hours at a time. Most of the time I never use the two in the front. I am unsure of what brand they are. They were some fans that I had lying around. They clear all of the braces on the front.
(http://i493.photobucket.com/albums/rr299/69byrd/truck011.jpg) (http://s493.photobucket.com/user/69byrd/media/truck011.jpg.html)
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I'm thinking maybe this will be a good setup..??
http://www.summitracing.com/parts/gri-cu-70008
that is almost exactly what we have, ours is a Griffin CU-70013. Great product, very well made. Note that there is a difference in Griffin's product lines between "direct fit" and "exact fit". That was not apparent to me at first. Difference is that on "direct fit" your stock mounts may not work. fabricating mounts was no a big deal, but it was another step.
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Great talks! I ended up going with a DeWitt's dual fan/radiator combo kit. I'm sure I'll have to do some adjusting, but at this point there isn't much left not to adjust for!
Thanks for all the input!