Anyone ever add a 16" or smaller pusher fan to the front side of the radiator to help from heating up when sitting in traffic? ( still running reg fan from water pump pully.- 22" 2 core champion rad.) When driving car it runs perfect, but sitting in traffic car starts to heat up quick.. can a elec fan work on the front to keep air flowing when stopped and still cool good when driving? - Thanks for any input!
Adding a pusher fan.
- Thread starter Cleary67
- Start date
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1968FormulaS340
Well-Known Member
Do you have a fan shroud? If running a clutch fan, is the fan clutch good?
A pusher fan may help but I'm betting, you have better options.
A pusher fan may help but I'm betting, you have better options.
MichaelB.
Well-Known Member
I have a 16" on the front of my '73 with a four core Champion. According to what I have gleamed a four core requires a pusher as a puller can't pull the air well enough through the width of the deep fins whereas the pusher reportedly can.
famous bob
mopar misfit
I`m running a 28x19 crossflow, 1 1/4" 2 row, 17" mech. fan w/ a home made but great fiiting alum. shroud. also have 15" elec. fan mounted in front of the rad., set to come on at 200* not a whole lot of time on the fish, but seems to be ok so far. ( no clutch)
Running a pusher with a mechanical fan just makes both of them inefficient. More than likely, all you will do is succeed in blocking enough airflow with the pusher fan that your car runs hot while it's moving too instead of just when it's sitting.
Your best bet is to sort out why your mechanical fan isn't up to the job, because it should be. Factory shroud, clutch fan, and a stock style fan combined with the right thermostat should be enough to keep your car cool unless you've got a much higher horsepower engine than stock. If you do, you may need more than a 22" 2-core radiator. Mixing electric fans and mechanical fans just reduces the effectiveness of both.
I run a 26" 3 core Champion radiator with a Ford Contour dual electric fan/shroud set up. Basically the entire OE ford contour set up minus the Ford controller. Works great. But I run the fans off a relay set up with heavy duty wiring (similar to what Ford did), use an aftermarket digital fan controller, and upped the amperage of my alternator (100 amps) to handle the additional draw. All things that are probably needed for any kind of electric fan set up to work properly. An electric fan that doesn't need those things won't push enough air to be worthwhile, and an electric fan that pushes enough air to be worthwhile will need those things to function the way it's intended to. A good thermostatic switch might work for some applications, but you'd still need the relays and extra juice.
Your best bet is to sort out why your mechanical fan isn't up to the job, because it should be. Factory shroud, clutch fan, and a stock style fan combined with the right thermostat should be enough to keep your car cool unless you've got a much higher horsepower engine than stock. If you do, you may need more than a 22" 2-core radiator. Mixing electric fans and mechanical fans just reduces the effectiveness of both.
I run a 26" 3 core Champion radiator with a Ford Contour dual electric fan/shroud set up. Basically the entire OE ford contour set up minus the Ford controller. Works great. But I run the fans off a relay set up with heavy duty wiring (similar to what Ford did), use an aftermarket digital fan controller, and upped the amperage of my alternator (100 amps) to handle the additional draw. All things that are probably needed for any kind of electric fan set up to work properly. An electric fan that doesn't need those things won't push enough air to be worthwhile, and an electric fan that pushes enough air to be worthwhile will need those things to function the way it's intended to. A good thermostatic switch might work for some applications, but you'd still need the relays and extra juice.
famous bob
mopar misfit
read my above post, working pretty well for approx. 700 h.p., the front 15" pusher fan is 2" off the front of the radiator-so as not to block air flow. when it came on today it held the temp steady at 200, that`s what I`ve got it set to come on at.
I removed the 1/2" spacer I had on the mech. fan, the fan blades are now just ahead of being centered in the shroud. I think it might have hurt it some, seems like it worked better w/ the fan closer to the rad. ???????????still tuning,reset the IAC, RICHENED THE ACCELERATION MIXTURE ONE CLICK, AND THE IDLE MIXTURE ONE CLICK on the fuel inj. (clumsy fingures on the caps)
Never said it it was impossible. All I said was it's less efficient. And it is. No matter where you mount that pusher, it is disrupting the incoming air. Maybe not enough that it's causing you to overheat, but you can't argue with the laws of physics. Your mechanical fan and radiator would work better without the electric fan disrupting the incoming air. Your electric fan would work better without the mechanical fan disrupting the air it's pushing through the radiator. If running both is working it just means you have enough cooling capacity when the car is moving at speed that you can sacrifice some efficiency without overheating, because that is what you're doing. And that makes sense, since you don't have a fan clutch on your mechanical fan you're spinning it all the time, so you probably do have some extra cooling capability at speed. Of course, you also have unnecessary parasitic loss, because you're spinning a mechanical fan that you don't need in that situation.
Not to mention the added complexity and weight of running two fan systems, instead of just running one that has the right capacity and capabilities for your car. If you're going to add an electric fan, you might as well size it so you don't need the mechanical fan. Same for the mechanical fan, if you're going to run one you should make sure it has the capacity to cool the engine. And that means the right shroud, fan spaced correctly, fan clutch so you're not wasting horsepower when you don't need to, and a fan that pulls enough air. Otherwise you're just running two undersized fan systems, sacrificing efficiency and bumping up your parasitic losses.
I don't know a lot about laws of physics or about all the other complicated lingo that some of you guys come up with on here but I can tell you this. I am running a slightly modified 440 that had some heating problems with an old radiator. I have no gauges on it other than the factory gauge in the dash. Don't trust it. I just replaced the radiator with a Champion 526 and I replaced the thermostat with a new 180* just because I wanted to know what I have. I am running a factory 7 blade fan, no clutch and it has a spacer sitting about 1-1 1/2 " off the radiator. It cools fine running. Sitting in traffic, it climbs some. How much , not sure as I have no temp gauge. I purchased one of those infared thermometers that some on here suggested and it doesn't tell me much so I am going to put a 16" pusher on the front of this radiator just because it makes sense to me. While running down the road I don't think that the pusher will impede much at all because of the space it blocks on the front. And when you are in traffic, if you set it to come on at about 195*, it will keep it from running hot. I don't think anyone on here can dispute this because it is common sense to me. With a factory fan pulling and a pusher fan pushing, it has to cool. As far as a shroud goes, I am not running any. Why, because a reputable radiator shop told me that a shroud will do you no more good IF your fan is no more than 1 1/2" away from the radiator. He told me if my fan is sitting within 1 1/2" from the radiator a shroud will not help me. I was going to spend the money and put one on. So Cleary67, I am getting ready to do the same thing you are talking about. I just need to get the time. I plan on running this car in a parade later this year and that is the only way I know to do it. 72bluNblu, I don't know where you get complexity and weight of running a 2 fan system. It isn't complex and the weight of an electrical fan is minimal. Not to mention that I would never consider running just an electrical fan on a car. If the electrical fan goes out or blows a fuse you are screwed. At least if you keep the mechanical fan on the car you have a way to get home or some kind of cooling.
furyus2
Well-Known Member
Seems You have your mind made up, but I had a similar issue. Hot at low speeds, and idle. I built a temporary fan shroud from some cheap aluminium from Home Depot. Worked perfect. No more issues. What that guy told you about a shroud is crap. You need one. Reconsider what you've been told already on this site. It's good,solid info.
I tend to agree with trudy. However, if your main heating issues are on idle you can have 400 fans but if you dont have capacity in cooling system,
doesnt matter. And yes. a shroud is there mainly for stopped extended idle durations.
I run 2 trans coolers under dash as extended cooling system capacity. One pusher 16" front of 3core alum. rad. and aftermarket trimmed down flex fan and 3" homemade alum shroud on 500HP steel head, BB,dualquad, tunnel ram,w/nitrous as well running straight advance.42* Mostly street driven. 190* tstat. Good for 5min. at idle before heading above 200*( depending on outside temps)
doesnt matter. And yes. a shroud is there mainly for stopped extended idle durations.
I run 2 trans coolers under dash as extended cooling system capacity. One pusher 16" front of 3core alum. rad. and aftermarket trimmed down flex fan and 3" homemade alum shroud on 500HP steel head, BB,dualquad, tunnel ram,w/nitrous as well running straight advance.42* Mostly street driven. 190* tstat. Good for 5min. at idle before heading above 200*( depending on outside temps)
I don't "come up with" the "complicated lingo" that I use. It was part of the curriculum for my aerospace engineering degree. And the "lingo" I use here is the usually the simple version.
As for the rest of it, a fan shroud significantly improves the efficiency of the mechanical fan. Same reason that little gasket on the hood that sits on top of the radiator support makes a difference. If the fan is effectively sealed it pulls air evenly across the entire surface of the radiator. If it's not it doesn't, and without a shroud (or a hood seal) you're losing air around the radiator and fan. That's less efficient, simple as that. If you want to believe a dude at a radiator shop over an aerospace engineer about air flow, hey, knock yourself out buddy. Not my car, not my problem. Same for the fan out in front of the radiator. It absolutely disrupts the flow of air when it's not running. Sure the car might not overheat, it's not blocking everything, but you're losing efficiency everywhere and that's all just parasitic loss. Much better off with one type or the other. Pretty much every new car that rolls off the line nowadays comes with an electric fan and a 100,000 mile warranty. If they weren't reliable they wouldn't be there, the factories wouldn't want to lose money replacing them if they were constantly failing. Belts still break on mechanical fans, rivets fail and send blades into the radiator, water pump shafts fail or eat bearings, clutch fans stop working. All of that results in the same thing, no fan. At best. Popping a relay and losing the fans on my car doesn't even necessarily mean I'm dead in the water as long as I keep moving. Traffic won't work, but my fans almost never run when the car is going over 30mph.
As for the electric fans, if you're doing it right you're adding a higher output alternator, which is probably heavier. Plus the heavy gauge wire for the fan. Plus the relays. Plus the fans. It's not a ton of weight and it's not super hard, but it's all uneccessary if you can get by with a properly set up mechanical fan. And if you're not adding relays or alternator then you're either not pulling much in the way of amps, whichs means you're not pushing enough air to be worthwhile, or you're putting your stock wiring at risk. But you're not even running a temperature gauge that shows degrees, so, how would you know what temperature your engine is running?
Those infrared thermometers read surface temperature not coolant temperature, and the way the ir works the indicatated surface temp varies by material and even the reflectivity of the surface (i.e., painted metal will read a different temp than polished, rubber different from metal, etc).
Believe whoever you want. You think because what you're doing works it's the best way to do it, but I can assure you that's not true. Maybe the car stays cool enough and that's great, but you're losing efficiency, and that means lost power. If you're good with that, awesome.
Well you see, that is what I mean. I posted a thread awhile back asking if putting a pusher fan in front along with my factory fan was too much. I got more replies on stuff that wasn't relevant than was. That is where someone told me to check the temp with one of these infared thermometers. I don't believe you chimed in with your aerospace technology on that thread. maybe you did, cannot remember. Don't really care. So that is why I take what a lot of people say with a grain of salt. I just usually go with what I think seems logical. I think a fan in front along with a factory fan is logical because if the car is rolling you probably wont see the fan come on so it is like it really isn't there. And if you are stopped in traffic or something it will come on and cool it down to the preset degree so that is what you want anyway. Just seems logical to me. But what the hell do I know. I am not an aerospace engineer. I didn't think it took one to operate an automobile. I am just a dumbass body / painter man. just saying. But I might just take your advice and stick a shroud on there to see if it works better. I don't know. I tend to take peoples advice when they are in the business of what I need. I have known this old guy at the radiator shop for many years and he does know his stuff. maybe he missed the mark on shrouds. Not sure.
famous bob
mopar misfit
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
mech. fan, shroud, 15" pusher fan in front -set 2 1/2" off the radiator, set to come on at 200, works for me. w/o the electric fan, it will keep climbing at stop lights. I have a fair amount of h.p. too. -----JFYI . BUT, I'm` wondering, will a 7 blade-17" mech. fan suck more air than a 17" 6 blade fan ???????????
ask the aerospace engineer. he can probably tell you.
famous bob
mopar misfit
Lonewolf3165
Living the Dream!
Using both a puller and a pusher fan together is inefficient! I know there are the guys running both that will give you their example and testify how their car runs great. But the reality is it's not the best way.
Considering the fact that once the car gets moving at even slow cruising speed the fan does nothing to provide air flow across the radiator because the moving air from driving is greater than the amount the fan can provide. In a typical electric fan system the fans turn off once the preset temperature is achieved. The system is now relying solely on the moving vehicle providing the air flow to cool the radiator. Even with a solid mounted mechanical fan it's not pulling the air through because it can't keep up with the air flow when moving. That's why they started putting thermostatic clutch fans on cars. The fan just free wheels and spins like a pinwheel at cruising speed. It reduces the parasitic loss.
The point is that every fan has a threshold where it can't move any more air. At this point it just becomes an obstacle and causes turbulence. So getting back to 2 fans pushing and pulling. The fan that moves more air will over power the other fan and that fan becomes the obstacle. You would do better just having the fan that moves the greater amount of air and ditch the other. A well designed fan shroud is of major benefit as is a good air tight seal surrounding the radiator. Any radiator without either is at a disadvantage and the system loses efficiency.
Considering the fact that once the car gets moving at even slow cruising speed the fan does nothing to provide air flow across the radiator because the moving air from driving is greater than the amount the fan can provide. In a typical electric fan system the fans turn off once the preset temperature is achieved. The system is now relying solely on the moving vehicle providing the air flow to cool the radiator. Even with a solid mounted mechanical fan it's not pulling the air through because it can't keep up with the air flow when moving. That's why they started putting thermostatic clutch fans on cars. The fan just free wheels and spins like a pinwheel at cruising speed. It reduces the parasitic loss.
The point is that every fan has a threshold where it can't move any more air. At this point it just becomes an obstacle and causes turbulence. So getting back to 2 fans pushing and pulling. The fan that moves more air will over power the other fan and that fan becomes the obstacle. You would do better just having the fan that moves the greater amount of air and ditch the other. A well designed fan shroud is of major benefit as is a good air tight seal surrounding the radiator. Any radiator without either is at a disadvantage and the system loses efficiency.
Lonewolf3165
Living the Dream!
Additionally any electric fan should be operated by a relay not just a simple switch ciruit.
I understand what you are saying and I agree with you but what I am saying is that when the car is moving the pusher fan isn't working. When the car is moving the car is cooling enough that the pusher fan will not be running. It will be off because the temp will be not be high enough to kick the pusher fan on. The only time the pusher fan would come on is if and when you would get stuck in traffic and the temp would rise enough to kick it on and then it would assist the factory fan in cooling it down. While you are running at pretty much any speed the air would cool it down enough and the pusher wouldn't be on. I am not talking about having the pusher fan on a switch that runs all the time. It would be on a relay that when the temp rises above say 195* it would come on . That is the way I have it set up on the rat rod. It works fine.
Of your text book for Thermodynamics class....
Didn't your teachers ever say, "open your book to page xx and follow along...."
famous bob
mopar misfit
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SAME here. If, there was enough room in all A bodies, the ideal thermo-fan in the right size, in the right place, w/ a shroud would be ideal. Mine doesn`t have room for all that stuff, I was just stating what will work if one has to! I have so little room, I have to run a short mopar filter, to clear the shroud. And yes, when it out on the hi-way it`ll cool down by itself.
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