I installed K&N filters on my C207 and noticed avg 2-3 mpg and a slight power response on my throttle. I replaced my plugs and ignition coils and now have an avg increase of 6 mpg and noticeable responsive throttle. Overall no complaints, I will take a look for cleaning of my filters sometime end of this summer.

 

The question no one ponders about this is... Who wants to spend time cleaning these dirty filters when the time comes? It's a messy process. And you never really know if the filter is truly "clean" when done.

I have gotten messy working on my cars more times than I care to count. On important things, such as oil/filter changes, changing plugs, and periodic problem solving, like servicing MAF sensors, etc. But spending a half hour of my time getting messy for a lousy engine air filter pushes it too far, IMO.

As I noted earlier, I have used a K&N filter in the past. But its first cleaning had me asking myself, "What are you doing?" So today, I buy a new filter and move on down the road.

 

The AFE dry filters can be easily cleaned in less than five minutes.

 

Mahle or Mann and call it a day. Order from FCP and only pay once.

Unless of course:
-you're tracking
-and you live your life a 1/4 mile at a time

 

There are slight short term benefits using K&N, and ive had alot of fun over the years using this filter. However, a few good points were made. I found out my air filter was changed 15k miles ago by MBZ so there truly isnt any need to change it at this time. I appreciate your input.

dC

 

Perhaps... But think of all the other things I can do with 5 that minutes.

Besides, no matter how hard you try to shake out the dust, blow it with air, etc., the filter will NEVER look like there is no dust/dirt in it. It will never look clean, like new. Have you cleaned it properly? Who knows?

 

SMH.

 

FCP for the win.
If K&N made a decent and reusable filter that works, I'd consider getting one (2, actually, for the ML350). A set of Mercedes air filters for the ML costs about $120 (!!!). Got the last pair from FCPEuro and will keep doing so (pay up front, get the price refunded on return of the old filters) until they go out of business or I sell the car. Nice to have fresh filters for only the price of shipping.

 

I recently cleaned my throttle body and there wasn't any dirt in my intake system behind the airbox. I've had a K&N in for about 10k miles.

Edit: also that graph is visually misleading, even if there's a difference in filtration, it's only 3.13%, for 10 more horsepower that's reasonable, just change your oil earlier.

 

It is misleading in at least 2 ways.
Scales starts at 96%, so you are right that the difference in filtration can be 3% in this respect, when chart shows it proportionally much bigger.
But on other hand AC-Delco filter allows only for 0.07% dirt intrusion, when K&N 3.2%.
That makes K&N allowing 45 TIMES more dirt than leading filters.
It is up to individual interpretation if the result will be engine life shortened by 45 times.

 

I've heard that 1/4" galvanized screen mesh is good for at least 20hp.
Just change your oil more often and it'll be fine.

 

K&Nooooooooooooooooooooooooooooooooo


If you have got a turbo the dirt with shot blast the compressor blades .





Not hard to see why .

 

I use K&N because the best flowing paper would kill power in my truck, or any performance engine I tried, but also because I HATE having to change filters, or pay for them. With the K&N you can go substantially longer between cleanings so any complaints about cleaning or cost is easily offset compared to the multiple times you'd need to replace paper. I've had my E550 for two years now and the K&N have already paid for themselves. I live where it's dusty so if I did use paper I would likely have changed them 4x by now, because I care about power and because I care about power I refuse to use paper in the first place. Not sure how important it is on this car, but I'd say from experience, the filters are too small so for the engine so it's no doubt important.
Of course they don't filter as well, so that choice is entirely up to the owner. You know what choice I made, which is the same reason I bought the 550 over a 350.

There's also the oil on the MAF complaint, which I'm not sure is still a thing, but it used to be. Probably propaganda from paper filter mfgs worried about sales. In MB I've had with a MAF, they didn't care, and I always over oil my filters. The MAF was also super easy to clean, which is why I know they didn't care because clean or film of oil, or a new sensor, didn't matter. I say MB cars because they are the only cars I've had with a MAF and K&N.
I'm not sure the oil on the MAF was from the K&N because in my 550, with over oiled K&N in there for two years now, the box and tubes after the K&N's are dry as sun bleached bone in Death Valley.

K&N also makes pre-filters, as do other companies. The mesh ones, which are super popular for off-road, restrict flow as bad or worse than paper and I pity those that use them. I think K&N offers those too but I'd imagine only because people want them, thanks to Outerwears and their marketing. Like Slick 50 and so many other products that have proven marketing is far more important to sales than the products performance.
The K&N red foam (# 25-3930) doesn't restrict, or restrict enough that I can tell. Don't confuse it with other foam filters on the market that do restrict, which are usually dark gray or red but have much smaller cells. Those are usually primary filters, like you'd see on dirt bikes, generators or misc things other than cars. I just checked and the price of K&N 25-3930, like many things, has gone through the roof since Covid. The government claims ~6%/yr cost of living increase since Covid, but I think they meant 60%/yr. Or maybe they meant income because nobody's income I know of has come anywhere near matching cost of living. I paid $22 for that prefilter two years ago, and I think retail was $50?. Now retail is 140...

So the std cotton gauze K&N with the red foam pre-filter is, imo, the best setup. No power loss, much easier to clean, and some unknown % more filtration than just a plain cotton K&N.
I've used the K&N cotton and pre-filter on my truck for more years than I care to admit. When in the desert playing in the dunes the pre-filter, or filter before I bought a pre-filter, will be packed with so much dust that you can't even see the filter. Well, the front half of it, the back side of the 4x14" round filter is just regular super dirty so you can still the pleats. Despite this, no power loss that I can feel, and certainly not even close to the loss I get with the best flowing brand new paper element or one of those stupid Outerwears.
It's a pita to get clean the cotton when you're in the desert and don't have a hose and plenty of water, which is one reason I bought the pre-filter because it's substantially easier to clean. The other reason was all that frikkin dust! The foam catches almost all of it so no need to clean the cotton-gauze at all the entire time I'm at the desert.
I plan on putting the red foam in my 550, just need to figure out a good way to do it since it's pretty tight in the airbox.

 

.... because youlve bought into their snakeoil advertising.


I've seen tests where they took a stock filter that was filthy, covered 2/3rds of it with tape, and dynoed the car with that dirty/blocked filter vs no filter at all, and the numbers were indistinguishable. so explain to me how a K&N can perform /better/ than no filter when the dirty/covered stock filter performed the same.

and K&N really do not filter very well. If I see any trace of K&N on a used car, I immediately walk away.

the stock filter on a E350 takes a couple minutes to swap, this is something you do once every 50K miles or 5 years. OE Mann filters are $30 or $40.

p.s. this is the Mercedes forum, W212 section, not baja racing trucks.