Anyone do a fan delete and put slim fans instead of the big doofy one back in?
 

if so please tell me the gains and losses of this... im looking to do this to my x5 and i was really contemplating on just buying the slim fans and just have em run once the ignition is on and turn off once the car is off... i think this will be better and free up some ponies

This seems to be a very popular on some of the other forums, especially the E46 guys. My personal feeling is this is not advisable. The cooling systems on the M5x motors are not sucking HP that is going to make much difference. What worries me is that the cylinder heads on the M5x are very susceptible to heat, they are extremely thin, so thin that you can not surface them and reuse if you overheat.

Thats a minimum of 2k if you toast a head gasket and closer to 4k if your head gets warped, most people throw in a junk yard engine and sell the car. There is simply no safe HP left on the table with the 6 cylinder M5x engines. If you feel under powered you should sell and buy a 4.4 or larger. BMW engines and the 6 in particular will take you well into the 100k range and 200k is not a problem with care. Look at it this way, BMW only found about 25HP in about 12 years of production, and much of that came from increasing the displacement. That should tell you how close to the limit it was designed and put into service with. I think the 6 cylinder BMW engine from 92-05 is possibly the most reliable and well built engine of it’s size ever produced, and there are some amazing engines in that field, none of which will draw more argument to my statement than the 3.0 Porsche flat 6. The rest of the contestants are to far behind to really make an honest run at the “best of class” 6 cylinder.

Don’t mean to hijack your thread, but I say the fan delete is not worth the 2 or 3 dyno HP to risk.

Cleaner, what 3.0 flat 6 Porsche engine are you refering too? They don´t have any 3.0 L engine!!!! they have 2.5L, 2.7L, 3.2L, 3.4L, 3.6L, 3.8L and the ones for the SUV´S the 4.5L V8 atmo and Turbo.
Apart from the GT3 , Turbo and 4.5L engines, all the other´s are far from reliable, I´m talking with first hand experience.
Had a blown out engine on my 2.5L Boxster back in 2000, and a blown out engine with my 3.4L 996 Carrera with only 30K miles on the clock in 2003.
There is well known RMS failure problem ever since 1997 in those engines that lead to many blown engine thrue out the years. Only the engine from the GT3 and Turbo which have the base of the old air-cooled engines are the real bullet proof Porsche engines, that´s why they don´t use the M96/M97 engines that are running in all Carreras and Boxster , on their top of the line model the GT3 and the 911 turbo, those Carrera engine were not made to receive forced induction, they are to weak for that.

J.Seven

These are the engine I am talking about, the H2o pumpers from Porsche are not in the class of best 6 cylinder every built. 2.7 had some case issues, the 3.0 and 3.2 were in the class of the BMW M50's in reliability and miles you could get out of them. I am open to hear other contenders. Some say the early Dodge slant 6 might be the best, some have claimed BMW stole the design.


911 incl S,Carr 1974 -1977 2.7 6 CIS Injection
911 (SC) 1978 -1983 3.0 6 CIS Injection
911 (Carrera) 1984 -1989 3.2 6 DME Injection

i've been running it on my auto-x e36 m3 for 5 years. There is a slight performance gain, but not worth it on a street car.

I removed the fan and fan clutch after it failed and took out my radiator. The X is cold natured beast anyways. I made a thread on it 2-3 years ago. just use the search feature on fan clutch failure.

Electric fan is much better than clutch fan. Although the key is to get an inteligent and reliable switch as clutch fan works harder, spin faster under load. Keep the original fan shroud is also important.

Electric fan reduce a lot of stress on components like water pump ...etc. I used to run them on my semi track R32 GTR and performance improvement is noticeable, acceleration and stuff.

I am still running without the fan. I havent had any issues until the past couple days. My expansion tank busted, I am now trying to find a mysterious leak and determine why I have to run the heat on full blast or she goes into the red. I am also lossing fluid pretty quick. No white smoke from the exhaust and she drives fine with no power loss. I am having a hard time convencing myself it could possibly be a head gasket. No white smoke??? any inout from anyone??

Heres my thread I made for the fan clutch siezing.

My 4.8is has electric fan stock.