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I've done this to many of my old Muscle Cars and it was worth 3-5 mpg. Biggest problem is making sure there is enough air flow to cool. Cubic Feet per Minute (CFM) and Area that it needs to cool on the radiator. On my old Firebird with a 400CI (6.6 Litre) engine I ran a 16" puller and a 12" pusher fan set up stagger to cover most if not all the core rows. I think it was in the neighborhood of 3000 CFM.

Also need to think about proper thermoswitches to control the operating temp for the fan. Also Electromagnetic Interference with the Radio and Computers.

As far as the set up for an e46 BMW, I have not looked at the set up for them, as far as what pulley run the fan.. There may be someone with this already done, or a shop that can do the mod.

Here are a few places to start.

http://www.horsepowerfreaks.com/viewproduct~BMW~540~~Cooling~Electric_Cooling_Fans~.html

http://www.truckperformance.com/pro...6d&sortorder=AADAAA&sf1=BMW&sf2=1991&sf3=325i

http://www.jegs.com/cgi-bin/ncommer...report?manuf=189733&cgmenbr=361&cgrfnbr=79169

http://www.summitracing.com/
 

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RednekWithaBMW said:
am thinking about purchasing an electric fan and removing the belt fan. has anyone else done this? i want to get some info on whether its good or not. what modz are needed besides the fan? like a different belt? :dunno:
The primary cooling fan on any E46 is an electric fan already. If you have an automatic transmission, the secondary cooling fan is belt driven, but has a clutch that disengages it when not needed, the manual transmission equiped cars have only an electric fan. Consequently you will not see any power or economy gains without causing overheating problems with the engine.
 

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jsc said:
The primary cooling fan on any E46 is an electric fan already. If you have an automatic transmission, the secondary cooling fan is belt driven, but has a clutch that disengages it when not needed, the manual transmission equiped cars have only an electric fan. Consequently you will not see any power or economy gains without causing overheating problems with the engine.
I think I'm going to have to disagree on this one. On an automatic car, the engine driven clutch fan is the primary cooling source. The auxillary electric fan is intended to improve a/c performance at lower speeds and control a/c pressures. It has been proven that a "puller" fan (one that is mounted on the engine side of the radiator) is far more effective than a "pusher" fan (one mounted on the front of the radiator). The clutch fan disengages (mostly) when engine temps are low, to aid in warm-up. The electric fan won't even come on unless the a/c is on, or it is a hot day. On a manual trans equipped 3 series, an electric fan is the only cooling source, BUT it is mounted on the engine side of the radiator which makes it more efficient. No OEM manufacturer would mount a primary cooling fan on the front of the radiator.
Back to the fan swap idea. I wouldn't do it if I were you. It is true that a belt driven fan can suck up 15-20 hp, but for reliability sake I would stick with what the BMW engineers picked. It is also nice to know that you have a back-up fan just in case. I run a big 18" electric fan on my '68 that pulls close to 5000 cfm of air (that's a lot). It also has a progressive controller module built in that varies the fan speed to properly control temp. These kind of things are a huge leap in technology for old cars, but new cars are usually pretty well thought out. I'd keep it stock, but that's just my 2 cents.
-Andy
 

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mmkay...jsc....i don't want to sound like an a-hole but look under your hood once. belt driven fan is definately there.

that you streetk14. i know its been done on muscle cars. i've seen it done on a few of em. my dad owns a garage and the one mechanic is a real gear head. has a '88 5.0 mustang. thing runs like a raped ape. i was with him while he was running a vette and they were doin 170mph. found out the speed from his friend driving the vette. he thought he was doin 85mph :rofl: but yeah...i know it can be done.

i've considered it cuz i had seen on a site(can't remember where) that someone had removed their belt fan and used electric. the kit i found has the thermostat controller and stuff included. only downside to removing the fan apparently is that there's an ugly bolt or whatever sticking out where the fan was. eh...its only gotta look pretty for me though right? ;)
 

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RednekWithaBMW said:
mmkay...jsc....i don't want to sound like an a-hole but look under your hood once. belt driven fan is definately there.
Not on certain manual transmission cars. My 323Ci does not have a mechanical fan. My wife's 323Ci has one. :dunno:
 

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The HACK said:
Not on certain manual transmission cars. My 323Ci does not have a mechanical fan. My wife's 323Ci has one. :dunno:
You are very right about that. I am under the hoods of bimmers all day, and I believe that all newer manual trans E46 cars have only an electric fan. It is a larger and more powerful fan than the standard aux fan. Automatic cars need extra air flow to cool the trans fluid. If you do remove the mechanical fan, you will be able to see the threaded stud that the fan clutch mounts on. This is also exposed on the manual trans cars that come with only the electric fan. Is it ugly? :dunno:
-Andy
 

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streetk14 said:
You are very right about that. I am under the hoods of bimmers all day, and I believe that all newer manual trans E46 cars have only an electric fan. It is a larger and more powerful fan than the standard aux fan. Automatic cars need extra air flow to cool the trans fluid. If you do remove the mechanical fan, you will be able to see the threaded stud that the fan clutch mounts on. This is also exposed on the manual trans cars that come with only the electric fan. Is it ugly? :dunno:
-Andy
My 2000 manual 323Ci only has an electric fan, so the age of the E46 shouldn't matter, automatic 323Ci s of the same vintage have the auxiliary belt driven fan with a clutch.

As you say, unless there are some anomolies, automatic equipped cars should have the belt-driven fan plus an electric fan, manual transmission cars should only have the electric fan.
 
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