Gilly, I thought I'd start a new post rather than hijack Luxury Addict's.

Ok, so what I've read from other posts here, the K&N contaminates the air flow sensor with oil and this somehow damages it? I've never heard of that before, how does it damage it? I'm guessing the oil coats and insulates the sensor and prevents it from reading temp correctly? I would think a blast of brake cleaner would take care of that? Shoot, let me know because I have one on my car and I was just about to buy one for another.

Thanks!

It will contaminate the MAF if you oil the wrong side or over oil the filter. Many people like to blame a product for their own stupidity. Besides that, Mercedes MAF's are known to be pretty much crap and will fail around 40,000 to 50,000 miles regardless. I have been a K&N user for over 10 years and have had no issues in any of my cars. At the very least, it is nice to keep the old filters out of the landfills.

Lots of people have had problems. My experience that that the MAF is touchy, and you must be carefule about over oiling the filter. In my opinion, there is a very fine line between over and under oiling the filter.

I get a bit paranoid about under oiling, used to race cycles, and saw what gets through if under oiled.

OTOH (on the other hand) I almost always get a seat of the pants increase putting in a K&N.

Why not try it and see if the performance gain is worth it? Start on the dry side, i.e. put the oil on evenly and sparingly.

IMHO, having a new SL, I don't want the dealer refusing to pay for a failed MAF when they see the K&N.

Greg

I always oil 'em up real good myself. I bought one for the 99CLK in April, but it looked dry around the edges like buttered toast at a truck stop diner. I sprayed it to bring it up to my standards, but now I'm a little worried.
I did a net search on cleaning the MAF in other cars, but after removing the difficult security screws holding it in, it isn’t at all what I expected. There looks to be a exposed zener diode on it, and a flat strip of exposed metal. Anyone know what the story is there??
The MAF, intake tube, plastic grid and screen are all oil and dust free so I’m just going to leave the K&N in there for now. Judging from its looks I would think you could soak it in oil.

Being a guy from the old school, I'll just post some thoughts. I've seen some of these KN filters with no requirement of oil saturation. They are supposed to boost air intake. How do they do that you may ask. There is another thread that follows a spectographic analysis of oil with a KN filter and shows high contamination. It could be that the extra air comes from a reduced micron rating of the air filter. I know KN filters come from racing where the engines are TORN DOWN AFTER 500 MILES. I suppose you could do that. Oiling the filter is what you do to lawn mowers. Is you car a lawn mower? Soeone here has used KN filters for 10 years, but how much driving does he do, and what is the real condition of his engines. Car mfgs have designed air filters to keep ring and cylinder wall wearing grit out of the engine. I think they know what they are doing. Do you think they would miss an opportunity to increase power if they could just change the air filter design? I'm sticking with a good quality stock air filter and get another 300,000 miles on my car. If your rings get ground to nothing by partially filtered air, how are you going to prove that it was that racing style air filter that caused the excessive blowby and oil consumption. Meanwhile the after market mfgs are banking your money while you try to figure out how to pay for an engine. That's just my take as a 30 year professional MB mechanic.

Peter

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OK, so you want to put keep the old air filters out of the landfill and put mass airflow sensors in there instead?
Once they are contaminated, they're junk.
Unless I see some test results from an independent testing lab, I'm not buying the performance claims either, but for something without a hot-film mass airflow sensor, I don't see a problem with using them.
I've never heard anyone claim the K&N's only create problems if they are "oiled on the wrong side", could be though, but never considered that.

Gilly

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My MAF went out on my E55 before I installed a K&N. Pretty much all Mercedes MAF's fail in short order regardless of a K&N.

http://www.knfilters.com/facts.htm#RESULTS

http://home.earthlink.net/~jeweldr/tech/air1.htm

Ooohh, controversial topic, I love it! I respect everyone’s opinion and I certainly appreciate everyone’s input!

Gilly:
Yes, maf sensors take up less space in land fills so I'm doing my part. Seriously, my chevota will choke on a paper filter so I know there is performance difference. My Benz motor is less than ½ the size, but so is the surface area of its filter. I didn’t “feel” a difference when I put it in, but I doubt I would notice if there was. I don’t disregard what you’re saying, but I think since I can’t feel any oil in the intake that I’m probably ok? Then again I don’t how much they can take before they’re damaged.
So that strip of metal is the “hot-film” maf you referred to? I was expecting a coiled filament when I opened it up. I delicately wiped its surface with a Q-tip and there was zero evidence of oil or anything, no streaking etc viewed with a 10X eye loupe. If it does go it wouldn’t be the first auto part I’ve broke in my pursuit of performance, I’ve got a box of expensive broken dreams on a shelf to toss it into.
Do you or anyone know how the oil damages it? Come to think of it, I wonder why they don’t just measure intake manifold pressure (or vacuum depending on how you look at it).

Autozen:
I agree a good paper element filters well, maybe better, but certainly disagree about car mfgs. I believe they use paper because it’s cheap and it works. If the mfg is willing to change the design or shape of a part to make more power, then cars would have headers, pre-oilers, use synthetic oils, transmission coolers, etc etc. But in their defense I can see them shying away from K&N because the element is easily damaged, and if you don’t wash and oil correctly you’re in trouble. So they’re certainly not for the general public.

SEC and Greg:
I oiled both sides, and well. Certainly not dripping, but probably double what was on there out of the box. A dry K&N is a useless K&N.

I thought the hot film looked like a chunk of black plastic.....been awhile since I looked at one. What the oil does to it is "contaminates" it, that's how I heard it described. And it's pretty delicate, it surprises me that you say you "decontaminated" one. I heard once they bite, they're junk, I guess I said that already though. Even a leaking air intake is said to damage them, just little pits from being hit by dirt particles, very sensitive to "anything".
The old injection systems used a "hot wire" sensor, and these were more durable, but not as good, I guess.
They used to use a intake manifold pressure sensor, and couple that with a barometric pressure sensor and sort of get info they wanted, but mass air flow is pretty much the industry standard right now, I thing intake manifold pressure, for a natural aspirated engine, is pretty passe right now...

Gilly

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I've yet to see any proven dyno numbers on naturally aspirated Mercedes engines with K&N's. I've only seen slight losses, especially with the older engines without MAS's to even worry about. Can someone post a genuine dyno test that proves K&N improve horsepower on a naturally aspirated Mercedes engine?

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Gilly:
No, I have not decontaminated one. I just read about it and am willing to try it if I need to. I don’t know why the MAF won over the MAP, I’m sure there’s a good reason, I just hope it’s not profit in the replacement parts dept. Yes, it looked like a chunk of plastic, but there was the strip semi-hidden within it. The zener diode is 100% exposed and at first glance it appeared that was all there was to it. I thought wtf, maybe it’s a magic zener, but then I saw the metal strip. I still have no clue why the zener is exposed like that.

EuroCoupe:
I hear ya. I think most stock cars could care less, but also factor in that most of a paper filters life is not spent fresh and clean. The K&N really shines when it’s dirty, meanwhile a dirty paper element is choking the motor out. I see a lot of dust where I live, especially in my chevota because it see off-road action. If I put a new paper filter on it I will feel a significant loss in power, but no loss in my K&N covered with filth and ½ the pleats literally filled with dirt. In fact, I gets so dirty so quick that I use a pre-filter most of the time. You need to be careful with those too, only one type can flow enough to match the K&N, and you guessed it; a K&N brand pre-filter. 

Some engines just like being stock, any changes and it will hurt performance. Example; some lose power with a freer flowing muffler. Is it the mufflers fault? No, the problem most likely lies in the fuel delivery and ign timing. All engines will make more power if they can breathe better, but they need to manage that extra air to do it.

I think what looks like a diode is the temp sensor for the engine management.

Gilly

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Chevota

To answer your question (" why MAF over MAP "), .......simple.
MAP only measures load & airflow, MAF measures the volume of air & temperature of the incoming air.
Cold air being denser than hot air, is therefore calculated into the fuel requirements of the engine, to maintain an optimum air/fuel ratio.
Been running K&N on just about every piece of equipment I've owned in the last 20 years, without any problems, including my 1990 GMC pick-up truck with 400 k miles on it.

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Ic, so a map with a temp sensor would be the most effective? It's been a while, but I think a map was like $50 and they lasted longer. I dunno, I still prefer a carb. They work, then 10 years later they still work. If they need a complete rebuild you're lookin at about $50 and a few hours work.

Yeah, but with a carb try cranking anywhere near the horses out of an engine like a lambda controlled fuel injection system, and not to mention increased fuel mileage and improved air quality.

Peter

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