Discussion in 'E39 (1997-2003)' started by JAMAICAN TWIN TURBO, Aug 24, 2008.
..How much of a difference do the K&N air filters make compared to BMW air filters?
K&N 5 Serier
I just switched to the K&N and did notice a small boost in power...now it could be a placebo effect or wishful thinking cause I spent $50....:
That's funny. I just replaced my air filter and thought too myself, "Wow, the car feels like it's driving smoother." Could just be in my head, but thanks for the answer.
Use OEM. BMWs air intake system is pretty well engineered to begin with. If BMW could have given you 10 extra horsepower by creating a better air filter, don't you think they'd do it? I mean, at the very least, they'd have a reason to charge you 50+ bucks on an air filter. If there is a performance increase due to using a K&N air filter as opposed to a new OEM filter, it's because it's not filtering as well as the OEM filter, therefore allowing particles to enter the intake which could be catastrophic is the long run.
Now I'm not saying your engine will blow up next year, but you really should ask yourself if it's really worth it when the filter your car was designed to use is so cheap.
You have probably notice that there is a substantial difference between the purists and the enthusiasts out there. I am definately the later...
Why would BMW try to get an extra 10 HP out of an upscale sedan by re-designing the air filter? Well...they wouldn't.
The fact is that BMW and other mfgs rely on the aftermarket to provide additional equipment and functionality for specific applications. Dinan, Racing Dynamics, Bilstein and countless others take a look at the holes that BMW leaves (intentinoally or otherwise) and develop cottage industries for those of us who are looking for modest performance gains and can't afford an "M" series car.
The other fact is that K&N has been around forever...you don't get to hang around in this economic climate by producing substandard products that don't work and that people don't want. Think about it. BMW would have plenty to say (in court) about products that are advertised to be compatible and cause damage to the engine.
I say let the purists alone and let me enjoy my K&N filter!!!
Hmmm. Maybe because said 'upscale sedan' (the E28 535 and M5) is the fastest four-door you could buy in the US at the time? Nah; they wouldn't mess with that.
Why? Because they could easily decline any warranty claims from a puffed engine? Think again. They don't care if you install a TurbinatorÃƒÆ’Ã†â€™ÃƒÂ¢Ã¢â€šÂ¬Ã…Â¡ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€šÃ‚Â© as long as they don't have to pay for the damage it might do.
Sure. As soon as I see your dyno sheets showing a 10 hp gain from using it ...
^^^^ He called me a purist
Please read the thread. The 10 HP increase reference was not mine...I just said in my original post I felt that I was getting some increase....the key word here is "felt" that is a perception not a documented fact. Just like I "feel" that you want to argue for the sake of it and really don't have a point to make. Frankly I don't have the time for it...I'm too busy enjoying my BMW....maybe you should do the same.
Calm down, killa! Nobody's saying you're a horrible person that should be fed to the wolves for using a K&N. If it makes you happy, then by all means...! The OP asked for other members' opinions on them and that's what he got. You seem to be pretty short tempered for someone with no time to argue. Have a nice day and happy Bimmering.
K&N's still exist because of several reasons. One is because people think they add horsepower. Those stupid little intake cyclones are still around but that doesn't mean they work.
There are many tests out there showing the K&N filters do not work as advertised. Placebo effect.
Well, me an' ole WVE28 here will be roomies at O'Fest in a couple weeks, so if you want to join up with us and see how guys with BMWs old enough to vote enjoy them, you'd be welcome. Just don't leave your hood unlatched at night or you might find your air filter run up a flagpole ...
Sorry to hi-jack the thread, the quote about the tornado/cyclone brought back something I saw at our local BMW dealer in the service bay about 2 years ago:
Brand new V10 M5..........with two decals under the hood proudly the declaring the Tornado Gas Saver was installed......
So I take it you have no mods on BMW at all huh? Classic, I can dig it.
Oh, not at all! No sentient being with a 3.5 E28 keeps those stupid metric TRX wheels around, so that's always the first thing to go. Then, there's the suspension to consider. Urethane control arm bushings, sport springs, HD shocks, etc. E32 and E34 brakes bolt right into our smaller, lighter cars. I'm just not a big fan of spending money that doesn't really make any significant difference in performance. Long before I'd start rethinking the perfectly good E28 (or any BMW) intake system, I'd spend the money on a Motronic chip for a little better power curve and a slightly higher ignition cutoff.
Of course, this is not to mention the Saab glass moonroof panel in my 535 ...
These things are fun to read.
At least you're civil with one another.
In addition to actual tests showing there is no imporvement using a K&N filter there is one big reason you shouldn't -- the slightest over-oiling of the filter element will degrade the performance of the airflow meter and you'll end up with, at best, worse performance and in a worse case, hosed cats from the computer trying to adjust fuel and timing to address inconsistent readings between the pre-cat oxygen sensors and the airflow meter.
If the believe is that the stock paper filter is more restrictive than a K&N (and the difference really produces measureable horsepower) you may want to try running without filters which will result in the least restriction.
Problems with K&N
Hi All... I am a brand-new member, just recently bought my first BMW, a 2002 540i. I am a pretty good mechanic, having raced American (Ford) and Japanese (Honda) for decades, but I have never touched a BMW before. I was about to purchase a K&N, but I stopped by a highly-recommended BMW shop here in Houston and talked to the owner about using a K&N. His response was a strong 'NO !" and he stated the same reason(s) as Louis said (see previous post). I was shocked, but he said the K&N almost always creates problems with the Mass Air Flow Sensor. His strong recommendation was to stick with OEM.
My question to all of you is this: where does one find the best online prices for OEM BMW parts? (including the air filter I need !)
Welcome to your first BMW!!!
OEM filters are always best. Glad you heard the same thing from your mechanic.
Not to defend K&N, but I think the problem is more operator error in the cleaning and recharging process. My guess is that people use too much oil on the filter and don't wait for it to dry. Then the oil gets sucked into the MAF. I like ITG foam filters, and can easily make the same mistake. When I do my inspection I or II, I clean and recharge the filter first, then do everything else on the car. And wait until it is absolutely dry before reinstalling.
For OE, I buy from http://www.getbmwparts.com.
Think about it...
This topic has been discussed ad naseum at BF.c and the jury is still out...LOL! Opinions are like a-holes, everyone has one. Well, from my research, we all know there is something in-line to measure airflow called a MAF/HFM5 (Mass Air Flow Sensor or Hot Film Meter). These sensors are just that, sensitive measuring devices and the oil from the K&N filter tends to follow the air flow and leaves an oily film on the MAF sensor components over time, which in turn causes poor engine performance since the sensor can't operate as it was designed.
Soooo...purists or enthusists should agree that making a sensor dirty with oil will certainly cause that component to operate improperly or fail completely. Use a high quality dry filter (don't skimp cause it's a BMW) and clean it frequently between changes FTW...believe me, it works!
Go here to read about cleaning your MAF: http://forums.bimmerforums.com/forum/showthread.php?t=833346
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