snowmuch

My B service is coming up and I'm looking to get a new air filter for my car before the stealership takes my arm and leg away from me for their oem filters. I did a bit research on the K&N drop in filters(33-2181) and got a mixed reviews on it. Half say they work great got a little horse power out of it and the other half got MAF sensor error.

What kind of air filters do you guys use?

AkaSigFreak

I order the Mann filters from the internet and install myself. I have always used K&N filters in my vehicles until the Mercedes. The reported issue was from the excess oil from the filter getting pulled into the throttle body and damaging the MAF. I heard BMC filters are great but EXTREMELY expensive.

snowmuch

It seems that BMC filters are twice/triple what the KN cost ($80 per filter) . Any idea how much are OEMs?

Domm

Oem air filters will cost you about $30-40 for set of 2 on amazon.

until the end

im using K&N for one year now and i didn't have any problem with the maf and i clean it every 10.000 and i notes that the air box have less dust and dirt after the filters ie it clean the air bater then the OEM
i didn't notes any increase in the HP but the sound is bater
sorry for the bad English

C300S 6MT

I used K&N for about a year. Didn't really noticed much of a difference. Didn't want to risk problems with MAF sensor, so I went back to OEM.

Cleanbenz

Been using K&N since I bought the car 7 months ago and zero issues. Just have to make sure you don't over oil it when cleaning the filters and you'll be fine

snowmuch

Thanks for the input guys!

Glyn M Ruck

The OEM filters are excellent. Don't mess with them.

Samaral

Just out of curiosity, how much MB charges for the air filter?

Domm

I think around $60 for the service which includes the filters.

HIGHLANDER S-55

I use K&N on one S55 and BMC on the other. Never any issues. Letting your engine breathe has to count for something in terms of HP.

Knightmare69

Had the K&N drop in for a couple of months, had no issues. Changed over now to the Burger Tuning Intake.

malahhaor

Green, k&n or BMW, they will all give a tad sound and better flow resulting in just a couple of hps and a tiny fraction in milage increase. That is my experience with filters since I've been driving. I have seen same results on rice rockets in my teenage years as on Benz.
However, some may argue that they do not filter as well and will eventually cause premature wear and tear.

bigben320e

I have been using K&N filters for over 5 years in my E320 and CLS. No problems with CEL, MAF issues, the problem comes in from over-oiling them. They last much longer than OEM filters, the price more than balances out.

One thing to add, if K&N filters were such an issue why does Renntech, Kleeman, and so many other performance shops use them and heavily? Just a thought.

Glyn M Ruck

I don't think that K&N filters are an issue per se. I think how you use them COULD be an issue. If you are modding the car with inlet manifolds, headers, increased bore TB's etc to increase airflow through the engine they would probably make sense. Remember that tuners are not bothered with engine longevity.

With a stock engine I see little point in changing from OEM. At stock breathing rates the OE filters do not provide high restriction or pressure differential across the media.

kevink2

If a filter like that is over-oiled, it could cause issues with the MAF sensor.

But my experience with my 3rd Gen Rx7, which I pushed from 255 hp to 320 hp for mostly HPDE use, is that the K&N Drop In for that engine made zero difference in airflow. I used a Dwyer differential pressure gauge to measure the pressure drop across the filter. I 1st measured oem vs K&N vs none and all measured the same back pressure at the high end. The entry into the filter box was the limiting restriction. I then fixed that, and found the the K&N and OEM still measured the same.

Now the Greddy front mount IC had high pressure drop due to a a small opening at a sharp bend in a cast inlet nozzle. One day with grinders and thickness calipers took care of that issue.

Point is unless you know it will make a significant difference, based on flow tests or dyno runs, don't bother.

.

Glyn M Ruck

Interesting Kevin and not surprised.

bigben320e

Good stuff and some good discussion points.