Removed my Fan! - The Unofficial BMW M5 Messageboard (m5board.com)

mottati · 3rd January 2005, 23:57

I took out the mechanical fan this past weekend. This is a common mod on e36 and e46 M3's, supposedly worth 8hp on a dyno. The electric pusher fan is still there, for idling in traffic. I may get an additional electric fan before the weather warms up, if i feel any difference in power. Initial impressions are minimal, I pretty much i don't notice any change, not that I could feel 3-4 hp if it actually gained anything. At idle, the engine seems to rev a bit freer, but it could be the lack of fan noise...
What can I say, the weather was bad and I was bored, this is a 3 minute mod! (it is surprising how much noise the fan made, now that it's gone!)
Mike

MAH · 4th January 2005, 00:12

Ok, I guess you are now going to remove the power steering as well! Have your thought about the Evosport power pullies?

Mark

jjc1843 · 4th January 2005, 00:18

Mike:

Do you think the standard electric fan will be enough in July in bumper to bumper traffic? I think "mr bock" has a full electric fan setup. Let me know how this does in some spirited driving runs.

kees · 4th January 2005, 00:27

Quote:

Originally Posted by mottati

I took out the mechanical fan this past weekend. This is a common mod on e36 and e46 M3's, supposedly worth 8hp on a dyno. The electric pusher fan is still there, for idling in traffic. I may get an additional electric fan before the weather warms up, if i feel any difference in power. Initial impressions are minimal, I pretty much i don't notice any change, not that I could feel 3-4 hp if it actually gained anything. At idle, the engine seems to rev a bit freer, but it could be the lack of fan noise...
What can I say, the weather was bad and I was bored, this is a 3 minute mod! (it is surprising how much noise the fan made, now that it's gone!)
Mike

If you happen to be able to plan in a dyno of the car with and without the fan that would be quite interesting.

shadowman · 4th January 2005, 01:20

There is nothing wrong with removing the clutch based fan, I do it on all of the Supercharged conversions and have considered the same on NA applications as well. However, I would highly recomend replacing it with a good electric fan. If the motor were to overheat it will become a very expensive service call.

With regards to the pusher fan that you spoke of; it is the aux. AC fan and is not designed to cool the radiator.......Its primary purpose is to cool the condensor core for more efficient AC operation in the exteme heat.

Take care,

Shadowman

ELEVENS · 4th January 2005, 03:44

My fan has been out for a couple summers now and no problems, but 90+ degree days are uncommon where I live. I weighed the fan once, but forgot the reading. Maybe about 6 pounds...

edit: it's 4 pounds.

bayerischemotor · 4th January 2005, 03:52

How did you remove it? You mentioned a 3minute method?

I'm not so intrested in the couple of horse powers, but if it makes the car idling and running quieter that's enough for me.

mr_bock · 4th January 2005, 04:16

Quote:

Originally Posted by bayerischemotor

How did you remove it? You mentioned a 3minute method?

I'm not so intrested in the couple of horse powers, but if it makes the car idling and running quieter that's enough for me.

Removing the fan is super easy... put a big wrench on the nut (where fan meets the engine) and give a quick smack to the wrench with a hammer. Caution!!! REVERSE THREADS!!!! Spin the nut free and out comes the whole fan. When I first did mine, I drove the beast for a few miles to see how it felt. The only thing I noticed is that the rpms stayed higher between shifts. Due to less inertia/drag??? My temp was going up some while sitting at stop lights, so I added the electric fan (pulling air throught the radiator). Something different?, minor enhancement?

LOL

mottati · 4th January 2005, 04:27

Mr Bock has it right. Big wrench (i used a crescent), wack towards the right it spins right off. Nothing else needs to be removed too get it out.

If i get on a dyno anytime again soon, ill try both with and without.

MAH: i already have the pulleys!

I will either re-install it or go the electric route, before the weather gets warm. Today, with plenty of driving around town in traffic, coolant temp never went beyond 12 oclock (i know that is meaningless), at low load cruise it's at my normal 'wintertime position' of about 11 oclock. Oil temp never over 200, usually around 180. So i'd say it's ok for 50F weather. The aux did kick on a couple of times at prolonged traffic lights etc. No changes under hard acceleration either (as far as temp), but again, it's cool outside.

Another plus is no worries about the self destructing OE fan/clutch assembly. I figure if that were to go, in addition to a rad and hoses, i'd be shopping for new cai tubes!
Mike

2003 M5!!! · 4th January 2005, 04:31

mr bock,

what type of project (approx. time and expense) is putting in an electric fan? Did you do this yourself?

Thanks.

Quote:

Originally Posted by mr_bock

Removing the fan is super easy... put a big wrench on the nut (where fan meets the engine) and give a quick smack to the wrench with a hammer. Caution!!! REVERSE THREADS!!!! Spin the nut free and out comes the whole fan. When I first did mine, I drove the beast for a few miles to see how it felt. The only thing I noticed is that the rpms stayed higher between shifts. Due to less inertia/drag??? My temp was going up some while sitting at stop lights, so I added the electric fan (pulling air throught the radiator). Something different?, minor enhancement?

LOL