K & N air filters vs. OEM?
 

I recently went to an auto parts store to purchase a replacement air filter for my 124 300TE 4Matic, and the salesperson tried to convince me to purchase a K & N filter instead of the stock air filter, claiming I'd immediately get better gas mileage and performance, (to justify the triple amount in cost I perhaps?). But since the air filter is housed in a steel case, I'm doubtful of the "more air" claim and even the better gas mileage, though I could use any increase in performance I could get! However, I've heard that the the K & N air filters are not as good as the oem because they don't catch as much dirt. Is this true? Anyone have correct information or experience? Thanks.

check the performance forum. someone posted dyno results of their car with and without the K&N. What he found was better flow with the stock paper filter.

Alon

Great, thanks for the prompt reply and informative response! I'll look for that, but by the sound of your post, like most things, the oem products seem to be the safest bet and the way to go.

Just curious, what type of air filter were you going to buy at this auto parts store? I don't know of any chain auto parts stores that sell any of the OEM filters for Mercedes.

On more than one car site, I've seen info posted indicating that K & N's flow more air and as a result allow more dirt into the system.

I suspect the MB engineers desinged the OEM filter to flow as much as is needed.

Hmm.....your comments have me a bit confused on this subject.

I've used K&N's in three of my previous cars with various results.

In the 4cyl VW engine I noticed a major change in throttle response as well as a 2-3mpg increase in gas mileage.

In the 6cyl Honda I didn't notice that much of a difference in throttle response however gas mileage did increase 1-2mpg.

Now what I've heard in regards to filtration is that the K&N's are better than a paper filter. They supposedly trap more dirt and will do this over a longer period of time (30 - 40K miles).

I'd really be interested in hearing test results that prove or disprove this, other than what's on the K&N website.

Whether or not you needed an air filter probably
 

has a lot to do with it, too. If your air filter was terribly dirty, anything would be an improvement. It would be interesting to do a back-to-back test with a brand new OEM filter, but I doubt that happens very often.

I have had good result with K&N filter on my Ford Explorer, my gas mileage increased 1-2 mpg after I replaced the paper filter with the K&N, at that time, the paper filter was still new, I had less than 5000 km on it.

K&N did make a noticeable difference on my Ford, after the replacement, the engine started to run very rough, I had to reset the ECM computer to let it calibrate itself, then engine smoothed out.

Haven't tried it on my 400E yet.

I saw many conflicting reports on the real value of K & N filter vs. OEM.
2 years ago, I had a chance to test an OEM and a K &N filter , back to back, on the same dyno on the same day with my 1978 Corvette (350cu.in, slightly modified)
Results:No change in HP at the rear wheel from idle to 4,500RPM. From 4,500RPM and up (stopped the test at 6,700RPM), the OEM filter delivered more RPM, with a peak of 7HP more with the OEM at 6,400RPM. The K&N rep, that withnessed the test was speechless.
Nobody can feel a 7hp improvement at 6,400RPM.
If (and only if) K&N flows more than an OEM filter, it does it at the expense of letting more dirt through. This is a simple law of physic that nobody can change. Even if it has the same filtration capacity as a OEM filter, the more air through it, the more dirt.
As far as increase in MPG, a 1 to 4MPG increase can be due to the driver, temperature, humidity, barometric pressure, and/or a combination of all those factors. For those who think they can ''feel'' a power advantage with the K & N, it has to be related to louder sound emitted by the intake system.
If K &N was such a supperior product, it would have been endorsed by a multitude of quality car manufacturers. To my knowledge, none have done so.
An other proof that a good marketing campain can sell (at a premium price) a product that is not better (sometime worst) than the original.
Just my opinion
JackD

After having read and considered everyone's sound advise, experience and reasoning, I am going to stick with an oem filter. Thanks.


1962 Mercedes 220SEb Sedan
1963 Vespa VNB 125 Scooter
1992 Mercedes 300TE 4Matic Wagon
1995 Subaru Legacy Wagon
. . . . and still collecting

Merci beaucoup, jack!

I suppose all of you are talking about the drop in filters from K&N, but what about the cone type filters. Are they better than the drop in and OEM ? I was thinking of changing my OEM filter with a cone type filter but after reading the posts I'm not sure I should do that.

I've been using K&N for years on different vehicles with variable results. My old 85' 500SEL and 87' 560 SEC felt great, mom's 400E was not as noticable. Then when working on my 94' E500, I talked to Renntech about some mods, including an enlarged airbox, in which they include some K&N filters. Renntech has a great reputation for reliable mods and extensive research and development precludes the majority of their work. If they trust it, so do I.

I went with their chip, stainless exhaust, filter box which gave me a definite boost in Hp and torque. Suspension went 17" rims and michelin pilot sports + a renntech swaybar. This package helped me dominate at a Audi club event at Road America (where shoving around brand new S4s came entirely too easy).

Bottom line, I like and trust K&N products, however, cleaning these filters is tuff and re-oiling them should be done carefully to ensure proper filtration.

I had K&N filter in my ML430. Did not notice any difference in performance or MPG. Oil analysis indicated silicon level abnormally high (bad filtration), much higher then with the OEM filter. In addition, the cleaning and oiling is major PITA. So i went back to OEM.
Mike

Interesting. Good way to go about it...

I agree.

I used K&N's for years on bikes and race cars, and don't think them a poor choice. But, otoh, MB OE filters are quite inexpensive, seem to do an excellent job, and I have oiled enough filters for a damn lifetime...