whats so great about the fan delete mod?

[328iThizz]

everyone talks about the fan delete mod and the problems that they have with it. But what exactly is the gain from doing this fan delete mod? I mean, if there isnt anything to gain, then why do it? I was thinking about doing it to my car, but im not convinced that there is a good reason to do it. Any comments?

[NegativeCamber]

have you looked at the parked thread at the top? the answer is in there. if you are too lazy to read, its done as preventative maintenance.

[Furious]

cliff notes- no substancial HP gains. if the fan breaks during driving it can damage lots of stuff.

[323iM]

That gain is that whetever you gain from deleting the fan you make up with 2x power being drained by the secondary AUX fan (engine slave labour, no?). In other words leave it ALONE!

[RahgBag]

The fan attached to the front of the engine likes to grenade and slice hoses, break radiators, dent hoods, and cause all sorts of meyhem. Plus, it does very little cooling. Therefore, understeer has a kit which gets rid of it. Very simple. No HP gains, a little more throttle response, and no risk of killing things inside the engine compartment.

[stirpicult]

That gain is that whetever you gain from deleting the fan you make up with 2x power being drained by the secondary AUX fan (engine slave labour, no?). In other words leave it ALONE!


umm, how is an electric fan taking away power from the engine? slave labor? makes no sense. there is no parasitic loss from an electric fan.



i have had mine on for 2 years after i had fan blades just randomly breaking off. if you do the kit RIGHT it poses no problems. it's idiots just taking it off and not finishing the mod that create the problems.

[takem2church]

he fan attached to the front of the engine likes to grenade and slice hoses

i can vouch for that. two weeks ago i was stuck on the highway with coolant everywhere waiting 3 hours for the tow truck. the second i got home and bought one. i have now installed it and got a new hose. good as new. fans are definatly ftl

[Lee101315]

thats all? just a hose? You lucky SOB.
Last night I slammed into second and destroyed the brand new radiator, fan, and hose. Nice.
Now considering the fan delete mod.

[325iklu]

My fan took out my expansion tank, varoius hoses and the shroud.

[choffa]

Unless you have solar cells on the roof, the electric fan will consume power from the engine (parasitic loss). Power to run fan's motor is generated by the alternator, which are notoriously inefficient (55% eff is normal, high eff units for special applications can reach 70%). Couple this to the fan motor's & fan blade's ineffieiency & the you're down well below 50% efficiency.

The blade design of the electric fan is of higher efficiency than the engine driven, but you need to factor in the system inefficiencies to determine if you are in fact saving power.

In other words there is no free lunch.

[Jeffrie]

^^^ electric fan does leach from the charging system just like say your power windows/sunroof/radio/headlights/blower or AC.
Although Choffa obviously never seen the Fan Delete or he'd know it's almost never on, while the belt driven fan is always on, although it does have a clutch to help take away the paresitic loss belt driven fans are natorious for on the hyway. Electric fan will never be on on the hyway and once every 5 min or so for about 30 secs ideling in traffic on hot days, which more then likly you'd also have the AC on which turns this fan on regardless even if you still had the belt driven fan.

[stirpicult]

Unless you have solar cells on the roof, the electric fan will consume power from the engine (parasitic loss). Power to run fan's motor is generated by the alternator, which are notoriously inefficient (55% eff is normal, high eff units for special applications can reach 70%). Couple this to the fan motor's & fan blade's ineffieiency & the you're down well below 50% efficiency.

The blade design of the electric fan is of higher efficiency than the engine driven, but you need to factor in the system inefficiencies to determine if you are in fact saving power.

In other words there is no free lunch.

power consumed off the alternator pulley is there with or without an electric fan. so, no, there is no parasitic loss which can be solely attributed to the fan.
and the electric fan creates no parasitic loss on the engine...maybe the alternator.
the alternator can't magically create more resistance on the engine, so if there is no new resistance, there is no parasitic loss.

[Jeffrie]

the alternator can't magically create more resistance on the engine, so if there is no new resistance, there is no parasitic loss.

Yes it can, the more apmrege needed for the electrical the more resistence (work from the engine) the alternator needs.

[1996Ken328IS]

ding ding! delivery v.s consumption. If the total consumption of the car does not exceed the output of the alternator, there will be no loss. However, if you do exceed the maximum output of that alternator, stuff will suffer.



power consumed off the alternator pulley is there with or without an electric fan. so, no, there is no parasitic loss which can be solely attributed to the fan.
and the electric fan creates no parasitic loss on the engine...maybe the alternator.
the alternator can't magically create more resistance on the engine, so if there is no new resistance, there is no parasitic loss.

[choffa]

Don't see anything wrong with the fan delete, as long as the electric fan is operating at low speeds (when ram air flow across the radiator is diminshed) it will be fine. Understeer's DIY specifies the lower temp thermostats to compensate. It's a good mod, I have several cars running without their original fans. It's the first piece tossed when building a high high rpm racing engine (Alfa twin cam & V6 engines). The reduction in rotating inertia is immediately felt. The parasitic loss is from the fan clutch's residual torque when disengaged (cold operation). Since it doesn't disengage 100% there is always an un-needed power drain.

[Doug001]

My fan took out my expansion tank, varoius hoses and the shroud.
Happened to me like this a few weeks ago... in addition to the above items, I also replaced the fan clutch, the two idlers and tensioner pulleys, both belts, water pump, and the thing that allowed the fan to hit the shroud: motor mounts! Change those damn motor mounts, too!

Motor mounts, belts, hoses, pulleys, water pump, fan, fan clutch, expansion tank, shroud, coolant, and labor: $1200.00

I shouldn't have trouble with the fan for another 14 years, and I doubt I'll have the car that long (could happen, though ;) )

[328iThizz]

alright, i think i understand now,m and for the most part, i feel like i am convinced. But what im starting to get from all this, is that the actual process of deleting the fan may be hard? From what i am reading, the success of this fan mod is decided by the person that is actually working on the car. It depends on thier skill level and if they do the delete properly. Is this correct? Lets say i went and bought the fan delete mod today. Since i dont know much about working on cars, would you guys suggest me doing it myself or taking it somewhere? And if i should take it somewhere.. where do i take it? what kind of shop? Thanks guys.. i got a lot of info from this thread...

[choffa]

Getting the fan clutch off the water pump can be tricky, you need a large (32mm) open end wrench & a tool to hold the pulley still while removing fan clutch (left handed thread). Bleeding the cooling system can be tricky, some guys have had problems with overheating after draining coolant.

Read through all of the posts in the sticky at the top of the forum page, plenty of good tips there. Also check Underasteer.com for a pictorial:

http://www.understeer.com/fanclutchmod.shtml

Parts are available there as well, or @ local dealer.

[gofastant]

If you've ever had a loose alternator belt, you'd be familiar with the embarrassing squealing noise that starts when an electric fan turns on while waiting at the drive thru for a mcdonalds double cheeseburger.

Ohms law:
V=IxR

[TboneM3]

FDM FTW /Thread

[autocross97]

If you've ever had a loose alternator belt, you'd be familiar with the embarrassing squealing noise that starts when an electric fan turns on while waiting at the drive thru for a mcdonalds double cheeseburger.

Ohms law:
V=IxR

what are you doing at the mcdonalds drive thru in your e36?

[carfiend]

gettin food like everyone else. dont you eat fast food

[doulos4jc]

everyone talks about the fan delete mod and the problems that they have with it. Who has had problems with the FDM? The vast majority of people on this forum have had ZERO problems. If there is an ongoing problem, it's with the fan potentially exploding without warning. Get rid of it ASAP and you'll gain peace of mind and quicker throttle response, if nothing else.

[thejaff]

The fan attached to the front of the engine likes to grenade and slice hoses, break radiators, dent hoods, and cause all sorts of meyhem. Plus, it does very little cooling. Therefore, understeer has a kit which gets rid of it. Very simple. No HP gains, a little more throttle response, and no risk of killing things inside the engine compartment.
This guy must have read every post I ever made about the FDM. Well said, well said.

+1.

[stirpicult]

Yes it can, the more apmrege needed for the electrical the more resistence (work from the engine) the alternator needs.


my point is that the efficiency of the alternator ALREADY takes into account how much work is needed from it. whether the fan is on or off, it is still expected to make a certain amount of power, and the fan is already designed into the system. nothing new is added, so there is no new resistance. and whats more is that the aux fan DOESN'T come on when under full throttle or cruising on the freeway, when power matters.



Getting the fan clutch off the water pump can be tricky, you need a large (32mm) open end wrench & a tool to hold the pulley still while removing fan clutch (left handed thread). Bleeding the cooling system can be tricky, some guys have had problems with overheating after draining coolant.

Read through all of the posts in the sticky at the top of the forum page, plenty of good tips there. Also check Underasteer.com for a pictorial:

http://www.understeer.com/fanclutchmod.shtml

Parts are available there as well, or @ local dealer.

can be tricky??? that thing sucks! word of advice to anyone doing the mod...spend the money and get the tool to hold the pulley. don't try and make it yourself. i did that twice using some thick steal, and literally applied about 1000lbs of force onto it (3 feet of pipe times me pushing against..easily 1000lbs;)) and all my homemade tool did was rip in half.

and there is a bleeder screw at the top of the overflow canister thing (i think). this will get the air out. maybe people are forgetting it:dunno

[doulos4jc]

can be tricky??? that thing sucks! word of advice to anyone doing the mod...spend the money and get the tool to hold the pulley. don't try and make it yourself. i did that twice using some thick steal, and literally applied about 1000lbs of force onto it (3 feet of pipe times me pushing against..easily 1000lbs;)) and all my homemade tool did was rip in half.
At least give it a try with a screwdriver or a homemade device before you plunk down $$ on a tool you will use one time. One long screwdriver and a whack of a hammer on the 32 mm wrench and mine came right off.

[stirpicult]

At least give it a try with a screwdriver or a homemade device before you plunk down $$ on a tool you will use one time. One long screwdriver and a whack of a hammer on the 32 mm wrench and mine came right off.

i think i found the tool for about 30 bucks. we tried the long screwdriver, too. bent it.

HA HA HA!!! found my original thread on it...
http://forums.bimmerforums.com/forum/showthread.php?t=191804&highlight=fan+clutch
here is the tool needed...
http://www.unofficialbmw.com/all/tools/all_fan_holding_and_tightening_tools.html
i bought this one...
http://victoryproductdesign.com/tools_main.htm

[doulos4jc]

i think i found the tool for about 30 bucks. we tried the long screwdriver, too. bent it.

HA HA HA!!! found my original thread on it...
http://forums.bimmerforums.com/forum/showthread.php?t=191804&highlight=fan+clutch
I assume you got the tool and removed the fan with no problems? It seems like some fans are on a lot tighter than others.

[stirpicult]

I assume you got the tool and removed the fan with no problems? It seems like some fans are on a lot tighter than others.

ya, got the tool. and after that, it was seriously like 2 minutes to get the thing off. very insane. just saw now that i never updated, but thought 2 years was a little late.:)

[brandonpturner]

gettin food like everyone else. dont you eat fast food

McDonald's in an M5. THAT is fast food. No one here eats in their cars.

[328iThizz]

alright.. good info.. now i know that i shouldnt instal it myself cause i probably will fu*k something up..s so where can i take my car to get the FDM? Hw much should it cost?

[Jeffrie]

my point is that the efficiency of the alternator ALREADY takes into account how much work is needed from it. whether the fan is on or off, it is still expected to make a certain amount of power, and the fan is already designed into the system. nothing new is added, so there is no new resistance. and whats more is that the aux fan DOESN'T come on when under full throttle or cruising on the freeway, when power matters.

Then fan delete would free up some power since it was desighned to work with AC (Aux fan on 100% of the time when using your AC) with the loss of extra resistence of the belt fan being deleted. Minimal since you can stop this thing with your hand provided it's clutch isn't engaged....Then I wouldn't dare try.





can be tricky??? that thing sucks! word of advice to anyone doing the mod...spend the money and get the tool to hold the pulley. don't try and make it yourself. i did that twice using some thick steal, and literally applied about 1000lbs of force onto it (3 feet of pipe times me pushing against..easily 1000lbs;)) and all my homemade tool did was rip in half.

and there is a bleeder screw at the top of the overflow canister thing (i think). this will get the air out. maybe people are forgetting it:dunno

Not everyones homemade tools work.....
I used an oil filter removal tool I had sitting around to hold the pully, put an adjustable wrench on the revearse thread 32mm nut and just tapped it loose with a hammer, then could spin it off with my fingers (2min job if even).
Had both the fan explode (not good, $300 + for fan assembly + new rad is another 350+ & many have had alot worse happen) &
did have one issue with this mod.
Sitting in traffic and the Aux fan fuse blows. Recomend a toggle switch bypass just to be safe (or hit the AC button, if your not too stupid like I was and just let it boil over).

[328iThizz]

bump

[Robstah]

The main cause of the fan gernading is the motor mounts. Some have been able to break blades off from hard shifting, but most of the time it is because the motor mounts get weak and allow excess movement. The movement normally puts the blades right up against the radiator. My old radiator had signs of this, even though my motor mounts are in really good shape.

Deleting the fan helps with a lot of things like the prevention of the gernading fan blades which can cause uber damage to a lot of things, easy access into the engine bay when replacing parts like water pumps/belts/and so on, and does cut back on the parasitic drag, but that is the last thing that you should worry about.

If you are doing everything right, you should replace your water pump, get a lower degree t-stat, lower degree coolant temp switch, add 2 bottles of water wetter to the system, and that should have you in tip-top shape. Most problems with this "mod" is when people just remove the fan and then start driving. This is a must if you actually care about your car.

[stirpicult]

bump

why did you bump it? your question has been answered a bunch of times in this thread already...

[amancuso]

...This is a must if you actually care about your car....


Or, you could replace your motor mounts and your old worn out cooling system and be safe for another 80-100K miles. I care about my car, so thats what I did.

[stirpicult]

I care about my car, so thats what I did.

:rolleyes
ok.

[BMLRacer]

Bay Area? Track down Vic Sias and get him to put the parts on for you.

I can't believe that some 8 years later you guys are still rehashing this. Oy Vey!

[elkniwirep]

i'm planning on doing a fan delete this weekend. i've got a 32mm wrench, but after reading all the horror stories about stuck fans, i'm worried i still may not be able to get it off without resorting to the special tool to hold the pulley still. if i understand correctly, though, what you're doing is removing the whole fan clutch, with the fan attached. IF mine's totally stuck and i need the tool, here's what i'm wondering: for now, can i just remove the fan from the clutch (is that even possible), leave the clutch on there, and do the rest of the fan delete since i've got all the parts from understeer? when i get my hands on a tool soon thereafter, i could then remove the clutch. but at least this way, the fan's gone (and can't destroy my engine, which is my main concern) and i'm not sitting on my hands on saturday, stuck and just wishing i had a special tool -- and i couldn't give two craps about residual parasitic drag from the clutch still being on there, if any.

or am i totally misunderstanding what's going on here? i apologize if the above is totally absurd. i'm a noob. :)