JWX Posted February 22, 2004 Share Posted February 22, 2004 on my 87 GL-10 it had a mech. fan and the elec one, so when I did the head gaskets I just left off the mech and planed on using the elec one. so will the fan turn on when the temp gets to where it needs to be, or is it just an extra one for when the ac is on? will it pull enough air to cool the motor? thanks for looking Link to comment Share on other sites More sharing options...
nutt7 Posted February 22, 2004 Share Posted February 22, 2004 If you can, wire a manual switch with a relay. I hear that these thermal switches on the rad fail often so you may not want to depend on it. You may be ok with just that one fan, but I would get another one asap...I recently got one from ebay for $40 shipped. type in '12 fan' and you will find some. my seller was fatrodder. oh yeah, diagrams for a manual switch are in the board somewhere, just do a search... hope I helped, eric Link to comment Share on other sites More sharing options...
bratman2 Posted February 22, 2004 Share Posted February 22, 2004 When you have a mechanical fan on a vehicle with a electric fan the electric fan is hooked up to turn on with the AC in every application I have ever seen. Is yours wired in to a temp sensor in the radiator? Should be on engine side of your radiator, they are mounted on the passenger side of a 87 Brat, don't know if that is relevant in your sisuation. I would think you would need another electric fan and a thermostat controlled switch to turn both fans on. I switched the dual electric fans in my Brat with 1 14-inch Hayden wired into the original thermoswitch, as far as reliability the switch in my 87 is original with 187k miles. Link to comment Share on other sites More sharing options...
Cougar Posted February 23, 2004 Share Posted February 23, 2004 Removing the mechanical fan is not such a good idea to me. This will make your electrical system work that much harder to supply power to the fan that will have to stay on continuously. This will make that much power less available for charging and these fans draw a good amount of current. The mechanical fan just uses a little power from the engine to run it. Link to comment Share on other sites More sharing options...
bratman2 Posted February 23, 2004 Share Posted February 23, 2004 Cougar, removing the mechanical fan is an excellent idea if done right. A mechanical fan will always use more hp than an electrical fan. With JWX I don't believe he will have any fan unless he turns the AC on and that might not be enough when hot weather approachs. Example, my 2000 F150 V6 supercab had a 10lb clutch fan, averaged 19.5 mpg with K&N intake and Magnaflow exhaust, replaced the clutch fan with dual thermostat controlled fans and average 21mpg and a big jump in low end performance. Fans only will run if idling alot are driving slow for extended distances, like off-roading. At speeds of 25 mph or more the fans should never come on unless a vehicle is under heavy load. Link to comment Share on other sites More sharing options...
JWX Posted February 23, 2004 Author Share Posted February 23, 2004 ok thats what I wanted to know(if it would kick on with out the ac) guess not. I'll have to find some and wire them up. anybody have any suggestions" Link to comment Share on other sites More sharing options...
bratman2 Posted February 23, 2004 Share Posted February 23, 2004 The Ebay tip was a good suggestion but you first need to measure to see how big a fan you can use. The 14-inch Hayden that I have will not alllow you to keep the AC fan so 12-inch might be your only option. I would want a high flow fan for cooling if that is what it is solely dedicated for. I would think you need 1300 cfm or more and they may be hard to obtain with some 12-inch aftermarket fans. You might want to find a 12-inch factory Subaru fan and an aftermarket thermostat. They are several kinds that can be purchased, mounts in radiator return hose (that is what is on my Ford), mounts in the top corner of your radiator fins, and wraps around the return hose externally. You may have a port that is capped on your radiator for a thermoswitch which would be best. Have you checked for a thermoswitch in your radiator? Link to comment Share on other sites More sharing options...
JWX Posted February 23, 2004 Author Share Posted February 23, 2004 kind of, but I'll look closer when I'm messing with it next adanvce auto parts has a elec. fan kit for like 60 or 70 I'll get that and wire it up Link to comment Share on other sites More sharing options...
bushbasher Posted February 23, 2004 Share Posted February 23, 2004 Why should a mechanical fan be less efficient than an electric if they are both always on? Electric is more efficient when it is being switched on and off when you dont need it. But you are losing efficiency through the alt, and then into the electric fan motor. A non-clutched mechanical fan is the most efficient if you plan on having it on 100% of the time. Link to comment Share on other sites More sharing options...
JWX Posted February 23, 2004 Author Share Posted February 23, 2004 who said anything about it being on all the time? thats not good for anything Link to comment Share on other sites More sharing options...
archemitis Posted February 23, 2004 Share Posted February 23, 2004 the ea81s came with no mechanical fan, and one electric fan. the ea81s come on earlier than the ea82 fans, because its just auxilary on the ea82s. my ea82s with the stock fan, and swithc got way too close to the red before kickin on. i like to have mine on a switch, so i can turn it on in traffic, or slow driving. Link to comment Share on other sites More sharing options...
bushbasher Posted February 23, 2004 Share Posted February 23, 2004 bratman says that a mechanical fan will always use more power than electric. This isnt true. For the same flow, an electric fan will take more hp from the engine because of the losses from motor to alt to electric motor. Electric fans are better because they are switchable wereas a mechanical is not. So overall less energy is used during driving. Link to comment Share on other sites More sharing options...
bratman2 Posted February 23, 2004 Share Posted February 23, 2004 Bushbasher, first I never said they would always be on, I would think the mechanical fans on a Subaru would still have a clutch just as an electric fan would have a thermoswitch. Second if clutch fans are better why does all the new Subarus come with electric fans? The only advantage to a clutch driven fan would be water submersibility in off road conditions. The lowest dynos I have seen on the new model F-150's show a low of 12.8hp gain by converting to electric with some over 16hp, this is from over a dozen individuals who have done before and after dynos. A clutch fan will cause drag on an engine even when disengaged. Link to comment Share on other sites More sharing options...
bushbasher Posted February 23, 2004 Share Posted February 23, 2004 electric fans are great, they are remotely locatable, they are easily switchable with no losses when they are off, wereas a clutch fan still takes some energy to keep it loosely spinning when it is off, and they are compact. What they do not do is give you 16hp. The only possible way you could gain power is because of a really crappy fan blade design on the mechanical fan, with a blade angle not suited to the rpm it runs. Even then the difference would not be even 10hp. 16hp is not even comprehendable in terms of human strength. 16hp to spin a 12" fan blade enough to cause a breeze? 16hp can propell you up to 60mph on a motorcycle, or lift a 2person hovercraft off the ground. A home fan probably makes close to the same cfm, but the motors are less than 1/2hp. When a clutch fan is engaged, it is like a straight shaft. How could you lose more power through a straight shaft than through an alternator, then through little wires, then to another motor? Converting motion to electricity then to motion again is really inefficient. I'd like to see what the standard deviation of the dynos you used are. Would the dyno give exactly the same reading every time? It could be that the dyno and the truck together can vary readings as much as 10hp with no modification to the truck. If the truck was dynoed, then driven somewhere to get the fan converted, then driven back to the dyno, that doesnt make for a very controlled experiment does it? Link to comment Share on other sites More sharing options...
JWX Posted February 23, 2004 Author Share Posted February 23, 2004 umm........ when did this turn in to an argument about mech fans vs elec fans? please stay on topic;) Link to comment Share on other sites More sharing options...
bratman2 Posted February 23, 2004 Share Posted February 23, 2004 JWX, I am not arguing just disagreeing as I think Bushbasher and I just as you both have a common fondness for Subarus. I have never dynoed my truck as I see no point, but let me explain, it weighs 4500lbs. has 205hp at the engine, to see any change I would think you would need at least 5-10 hp to notice any difference at all. The twin electric fans put more felt hp to the wheels than the exshaust and K&N intake together as they were installed by me together and the fans a month later. Also a 2000 F-150 has a 20-inch clutch fan weighing 10 lbs, according to the dyno charts that were posted on the F-150 forum when an individual brought up the exact same argument as you most hp was gained in the 2000-3500 rpm range (12.8-16hp) while around 5-6hp was produced at 5k. this has been well over a year ago and I don't remember all the points of argument. The person disputing the fan conversion was replied to over 50 times and still not convinced so I doubt you will be by me, 12 dyno charts were posted with none lower than 12.8hp gain. I know dynos are not very reliable unless a huge amount of money is invested and testing done under identical conditions. But not one individual produced a lower reading after doing the conversion. Flexilite and Permacool both make drop in fan kits for full size Fords and Chevy trucks at a cost of 400-550$ and they sell real well with not a single person ever stating they wanted to go back to clutch fan cooling. Now for JWX with his clutch fan on a Subaru he may not see 5hp do to a smaller fan. A Chevy 1999 model truck has 12lb clutch fan spining up front and that is alot of weight. Think about people that have their flywheel turned down for performance reasons, were does the power come from? I think JWX will see some small improvement by going electric. Hope I have not offended anybody and sorry for side tracking your post JWX. All Have A Good Day. Link to comment Share on other sites More sharing options...
Skip Posted February 23, 2004 Share Posted February 23, 2004 JW, to get back on track somewhat. and to your orig. question. The electric fan on your car will come on automatically. They all have a thermoswitch in the rad tank (pass side about half way down) I have been running my turbo wagons for several years with only the el. fan. BUT These thermo switches carry the entire fan current and are known to burn their contacts, a relay control circuit is a good idea. Here is a good link discussing this aspect of switching the fan. Switching for the el. rad fan Hope this helps get back on track. Link to comment Share on other sites More sharing options...
archemitis Posted February 23, 2004 Share Posted February 23, 2004 but if you use the stock thermo switch on an ea82... you will be cooking your motor because it doesnt turn on untill your too close to the red. Link to comment Share on other sites More sharing options...
Skip Posted February 23, 2004 Share Posted February 23, 2004 If the thermo switch is working correctly. It should turn the fan on at 199 degrees F. The factory recomended thermostat is a 193 deg F I therefore am confused by Arche's statement as in why would 6 degrees F over the tstat opening be cooking your engine??? Note these references are not from a guess, they are from the FSM Link to comment Share on other sites More sharing options...
JWX Posted February 23, 2004 Author Share Posted February 23, 2004 ok so the thermo switch in the rad WILL turn on the fan? even thou the elec fan was originally just for when the ACs on. Link to comment Share on other sites More sharing options...
Cougar Posted February 23, 2004 Share Posted February 23, 2004 If I understand the two fans correctly, the AC fan will come on with the AC or when the normal fan is not able to keep up with the thermal load. I doubt the AC fan alone will be able to keep your engine cool enough, especially in the hot South. I can see the points mentioned about having electric fans but I am also having trouble believeing one can save so much HP by changing over. Engineers rack their brains on ways to save on gas mileage and HP so I doubt they have overlooked this area, unless the production costs of converting them are too high. I may be wrong though. You brought up a good topic for discussion. If I were doing this to my car I would install a thermoswitch, 'Tee'd' into the other themoswitch, that would turn the fan on, at the same temperature as the themostat. The switch would control a rely tied through a fuse at the battery, to power the fan. Link to comment Share on other sites More sharing options...
archemitis Posted February 24, 2004 Share Posted February 24, 2004 ya, so 195, thats how many degrees away from boiling at 1 bar skip? pretty close, i know the pressure keeps if from boiling, but thats too close for me. if the guage goes past half thats too much. ea81s come on quicker because the fan is the primary cooling device. thats how my cars work, dont have a fancy book to tell me stuff i can observe. Link to comment Share on other sites More sharing options...
Skip Posted February 24, 2004 Share Posted February 24, 2004 I post the facts. If you want to post your casual observations, fine. Just do not state them as facts. BTW the coolant mix also extends the boiling point as well, and my EA82T fan comes on a little past half way on the gauge. Link to comment Share on other sites More sharing options...
archemitis Posted February 24, 2004 Share Posted February 24, 2004 but skip, arent you the guy that was runing around with no thermostat, to keep the pressure in the coolant system down? you said alot about how this is an inherant problems with our engines, so a few degrees here or there is a big deal. are ea81s and ea82 thermoswitches not different? Link to comment Share on other sites More sharing options...
Skip Posted February 24, 2004 Share Posted February 24, 2004 I will try to answer this with out trampling too much you ask: arent you the guy that was runing around with no thermostat, to keep the pressure in the coolant system down? Last summer (ambient temp approx 80-90 deg F, 20-40% RH) I was running with no tstat, I had two digital lab thermometers with thermocouples, one in the coolant and one in the oil. This was an experiment to see if running with no tstat would cause higher temps (and pressures as a direct result of higher temps). It was to learn first hand if the no tstat => overheat was an old wives tale. My particular test showed the myth busted. The oil came up to temp just as fast (this was a turbo'd car) and remained lower overall as did the coolant temp. I did not off road this car, and most travel was done on medium speed highways. No mechanical fan was on the engine. Rad was approx 20 kmi old. You say: you said alot about how this is an inherant problems with our engines, so a few degrees here or there is a big deal We do have an inherent problem with cooling our cars if the radiator is allowed to suffer fin delamination, turbo cars are more suceptible but all need this matter observed and dealt with. Esp. during the summer months. And you ask are ea81s and ea82 thermoswitches not different? physically yes, EA81 are single stud and EA82 have twin spades, same threads for the tank mounting. as for switching temps both the 83 and 84 FSM I have here say for the EA81 thermoswitch on --- 203 + - 3.6 deg F off ----196 + - 3.6 deg F pretty close to the Ea82 I posted earlier. Sorry to get so far off topic again, JWX is taken a beatin' Link to comment Share on other sites More sharing options...
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