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YOUR RESEARCHK & N M.A.F. statement
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Check paper filters are cheaper than mafs
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Last time I checked, paper filters are cheaper than MAFs.
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I recently replaced 2 MAFs on my M5, not because of failure but because of degradation over time.
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I've replaced a MAFS on a vehicle with no K&N filter.
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As a teenager (young and dumb), I ran about 40-50k miles after I rebuilt the engine without an air filter on my '69 Camaro and the motor had developed a lot of blowby over time.
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As a teenager (young and dumb), I ran about 40-50k miles after I rebuilt the engine without an air filter on my '69 Camaro and the motor had developed a lot of blowby over time.
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there's discussion from time to time on whether CAI's cause MAF problems and clearly it has become loud enough that at least K & N has reacted strongly with testing of consumers "defective" MAF's, and a bold warranty statement.
Interesting reading:
http://www.knfilters.com/MAF/massair.htm
Who says that corporations aren't swayed by consumer opinions!
Maybe no scientific evidence, but quite a bit of empirical evidence. It's hard to believe that it's a coincidence that many MAFs blow just due to age, right after a K&N oil filter was installed.
I had a K&N on my 2002 M3, on my 944, and have one on my 964.
That being said, I've seen too much evidence on this site to put one on my 996. I'm not smart enough to know why it's a problem on the 996, but I can't ignore the evidence.
Maybe if K&N would determine some way to quarantee they'd replace the MAF if the agreed upon criteria were met that pointed the finger at the filter.
That's easily proven or disproven with a before and after oil test. That's what I'm doing with my EVO. But I have to say, although there's all kinds of discussion about MAFS, I've never, ever heard anyone claim that their engine wore out prematurely because of oil contaminated by particulates not captured by an air filter. This one feels pretty speculative and theoretical to me.
I'm not saying the filtration performance is identical. I'm just questioning whether the difference is material, given the absolute lack of evidence that any harm has come to engines this way. At least on the MAFS thing, there are wrecked parts to argue over. What does damage from unfiltered particulates in the intake charge look like? Has anyone experienced this?
I believe that the oil on a conservatively oiled filter is not the culprit, but rather the location of the MAF sensor too close to the cone filter in the K&N intake, which results in a non-laminar, turbulent flow of air over the wire sensor element. My MAF blew about a month after I installed my K&N intake, and I have run a k&N filter (not overoiled) for over a year with no problems. Just my 2 cents.
I had a K&N on my 2002 M3, on my 944, and have one on my 964.
That being said, I've seen too much evidence on this site to put one on my 996. I'm not smart enough to know why it's a problem on the 996, but I can't ignore the evidence.
Maybe if K&N would determine some way to quarantee they'd replace the MAF if the agreed upon criteria were met that pointed the finger at the filter.
http://www.knfilters.com/MAF/massairpledge.htm
This is part of their discourse on MAF's and their filters. It would appear that they are prepared to replace our MAF's if we can prove that their filter caused the problem and therein lies the problem!
Happy Reading. Bob the Oil guy did a filtration test.
http://www.bobistheoilguy.com/airfilter/airtest3.htm
BTW, I have K&Ns on most of my cars (not on the 996 yet). No issues with my past +200k car's original engines. UOAs (Blackstone) came out fine with no abnormal engine wear.
Its seems that there are plenty of dirty MAFs in their tests. I have a question for you guys, have you ever had a vehicle that used a stock filter have a MAF issue? I also noted that only 3 Porsche's were tested, two of which did not have an independent test.
Good article, it proves you cant beat a paper element for filtration but the K&N did better than I expected.
If you look at the factory paper element, you will notice only about a 1/3 of the element is dirty, 2/3s of the filter is still clean. To me, this shows the paper is more than enough for airflow and still provides the best filtration.
I've replaced a MAFS on a vehicle with no K&N filter. MAFS are consumables, generally not meant or expected to last the life of the car.
Anyhow, again, I'm missing the part about engine failures due to poor air filtration. I don't dispute the differences in filtration, but are they material? It reminds me of the guy a couple of months back who said he didn't like to rev his engine too high because it would accelerate wear. Yes, in a vacuum, it will. But by the time it does any damage, the car will fall prey to a hundred other kinds of decay, a hundred times over.
Bruce - I made the comments above.
First, I have never heard of a MAF failure until I got around Porsches. I have been around 150k mile engines that have never had the MAF replaced. Maybe they were all lucky, or that Ford and Chevrolets have a superior MAF to Porsche? My Corvette had 126K miles on it and I didnt replace anything on the car. A lot of friends of mine have had give or take 150k miles on their Mustangs, Camaros, and Firebirds, again no MAF failure.
Second, if allowing debris into an engine isnt a big deal, run without a filter and get the most flow possible, right? As a teenager (young and dumb), I ran about 40-50k miles after I rebuilt the engine without an air filter on my '69 Camaro and the motor had developed a lot of blowby over time. I am basing my opinions on what I have done in the past and how I ruined motors.
Third, dirt bikes have to have top end rebuilt often, why? Life of high RPM. Sport bike motors have to have the engines rebuilt often, why? Life of high RPM. I read a report of a Suzuki 1000cc engine that after only 6k miles, lost 5-6% on leakdown over the engines new readings of leakdown. In the old days, engines lasted only around 50k miles (Fathers statement). With advancements of oils and reducing engine RPM with overdrive transmissions, engines have lasted 5-6 times longer. I read from a well respected 996TT tuner that forces/stress on the crankshaft is exponential with RPM, not linear. I would assume that all rotating mass works the same.
These are just my observations. Take it FWIW
Well, look, I haven't said anywhere in this discussion that less filtered air doesn't lead to MAFS failures. I've just said that I'm not sure it's that big a deal, if you believe that you're getting some benefit from the filter. As far as your past history is concerned, all I can say is that have seen other cars with MAFS failures, though interestingly none American, now that you mention it.
On the filtration issue, I think like any engineering decision, it's not black and white. The best protection is a plate of solid stainless steel. The best airflow is no filter at all. So, pick your compromise between the two. That's engineering. IF you believe that there's a benefit to the added airflow, then you accept the risks and minimize them where you can (doing more frequent oil changes, for example). I certainly did not say that "letting debris into the engine is not a big deal".
On your final point, no disagreement. An engine is an air pump. That's how it makes power. The more air it moves, the more power it makes. There are two ways to do this: Make it big, so it takes bigger gulps of air, or make it rev so that it takes small gulps but more often. All things considered, the former kind of engine will last longer than the latter kind. You just accept this when you choose this kind of motor, accept it for the joy it gives you. But I stand by my opinion of that poster's strategy of keeping the Porsche's rpms down to preserve the engine: He/she should have chosen a Corvette. Or maybe a John Deere.
My ML430 had it's MAF replaced and it uses a stock air filter. Also, my Indy MB shop owner showed me a pile of MAF's laying around the shop.
Also, on their list of dealerships that sent them MAFs, there were plenty of Chevy's.
About the same time as my 99 996 MAF sensor went bad so did the MAF sensor on my wifes 2000 CLK.
This was sometime in 2001. Both were replaced under warrenty. Both made by Bosch. Probably the same design. Still have both cars. No problems since. Do you think maybe the replacements were a redesign or manufacturing improvement? Maybe the silicone contamination problem from poor quailty control at manufacture. Both had stock filters. My 4-Runner never has any of these problems.
I have always considered Bosch to make low quality, over-priced components. More than likely the Toy uses Denso which IMO makes the best electrical components for the auto industry. To your point, a friend of mine has had 3 Tacomas that have made high mileage without issue, all off-roaded. One at 160k miles, and the other 2 made it past 200k miles without a MAF failure.
This is funny, look how dirty MAF cans get on Toys without failure and the belief that the OIL from the TRD (Toyota Racing Develoment) air filter gets on the MAF sensor wires. This is from a 4X4.com:
A dirty MAF sensor can cause rough idling or even a check engine light. The cleaning procedure is simple and inexpensive. Those owners who have installed a re-usable air filter (such as the TRD unit) will likely need this service sooner than others, since a small amount of the oil used on these filters is sucked in the intake tube and tends to coat the MAF sensor.
First of all folks, 964's 944's don't have mass air flow sensors, they have air flow meters. A 928 has a hot WIRE MAF that performs a "burn off" everytime the car is shut off. Porsches '95 and up have HOT FILM mass air flow sensor, no burn off. Second, A Porsche 996 or 986 is a bit special in that they make a lot of hp considering engine size and co2/ emissions output, at least for their time. This means very tight specs programmed into the DME(as required by EPA emissions testing) before CEL comes on. What does this mean? Well if a 68 Chevelle's fuel mixture was off by 4.5%, no one would know except God. If a 96 dodge neon's fuel mixture was off by 4.5%, the Pope might know about it. If a 2000 996's fuel mixture is off by 4.5%, bing, a CEL shining proudly. I won't deny high up confirmation of silicone contamination at production(though it took 10,000 or more to show up), but filter oil or silicone based products(amour all and what not) WILL kill a Porsche hot FILM MASS air flow meter, or at least out of Porsche adaptation limits.
This may be interesting reading for those that have a desire to read through it. I recently replaced 2 MAFs on my M5, not because of failure but because of degradation over time. Cleaning was a stop gap measure. It works for some and not for others. Many (including myself) consider MAFs a maintenance item like spark plugs and O2 sensors. Since fuel is ratioed to air flow, it's important to measure the air flow correctly.
http://www.m5board.com/vbulletin/e39...mafs-work.html
K&N's logic is a bit misplaced though. They are implying that dealers claim the K&N filter causes the MAF failures in an effort to sell more OEM paper filters? Last time I checked, paper filters are cheaper than MAFs. I'd sooner think that dealers would be more than happy to sell you more MAFs than more paper filters.
Personally, I think the issue arises because some people over oil their K&N or BMC filters and don't dry them with paper towels prior to installing them. Regardless, I still think the OEM paper filter element already does a more than sufficient job, and is much easier to use (just wait till the mileage is up when you need to drop in a new one, and throw out the old one)....no need to remove the oiled filter, clean it, re-oil it, and then reinstall.
This is a source reference. Confirm exact model applicability in the original material.
