Re: Junk Science, Part 3
you're right, we are not going to agree 100% Just like others swear by Dura-Lube, Slick 50, etc. Its hard to agree because we really don't have all the data to have an objective argument, and subjectivity necessarily comes into play.<p>As far as OEM, I never said that *all* aftermarket parts are inferior to *all* OE parts. Of course that is not true. But probably 90% are inferior.<p>I guess it really depends on the starting point one uses. I start with the presumption that the OE part is the best part for the job, at least on a quality car like an MB. That is a rebuttable presumption, but I need convincing, non-advertising, scientific proof to overcome that presumption. If that proof is there, I will use the aftermarket. That is the opposite of the starting point for many "enthusiasts." For some reason, many start with the presumption that the aftermarket product (based on advertising) is better than the OE product. They start with the presumption that the car Mfr didn't do a good job. That's just not my approach.<p>I guess I might agree that 50% of people are running around with low tires and clogged air filters. But, then again, 50% (or more) of average drivers are idiots that don't do ANYTHING to their car unless it breaks down. I'd say that just about anyone who participates on a site like this, or who even knows what a K&N filter is, is not an average motorist who ignores their car. In making decisions on what to use on my car, I do NOT factor in "Gee, what's better in case I ignore maintenance!" Its just not a consideration, and I guess I don't really get your point on that issue.<p>As far as K&N letting in more particulates, I've already explained why that is, based on K&N's OWN tests and numbers, which I personally obtained from K&N directly. I've communicated with them many times. One thing they will NEVER say, in communications or in advertisements, is that they filter better than the stock paper filter. They just won't say it. Likely because they would get sued or busted by the FTC. The answer is pure math, and is hard to dispute. You say that particulates below a certain size are "unlikely" to cause damage. Gee, even if true, "unlikely" is not very comforting, esp. when we agree that the K&N will not increase power!<p>Again, we agree on my main point: K&N will not increase power. The most you will say is that its "unlikely" to cause damage. Well, if it doesn't increase power, why mess with it? If you are going strictly on a cost saving basis, then I guess that's my answer, and I am not really interested in arguing on that point (cars are expensive, the cost of stock air filters, at least to me, is insignificant). In the end, I think we actually agree more than disagree.<p>Finally, other things I use on my car: oil filters: OEM only. Aftermarket filters, including K&N, Fram, etc. are junk. There is a lot of info on the net about aftermarket filters, and how they often have different relief valve systems, different flow directions, different construction, etc. from stock. I know that using the factory filter, I will NEVER have a filter problem. I cannot guarantee that with any aftermarket filter. Again, aftermarket oil filters are the answer to a question that no one asked. Motor Oil: I use Mobil 1 in all of my cars, and would never even think of spoiling it with an additive. I used it before, but it also came as factory fill in my MB. Spark Plugs: OE only. Tires: I tend to just buy decent, well-priced, brand name tires. Most everything else, I stick with OE on my MB, BMW and Porsche, with some minor exceptions.<p><p>: Well, I could point you to a Transport Canada fuel economy study which involved a random survey done in the 1980s of vehicle maintenance. This study indicated that the two major problems were underinflated tires (over 60% of cars) and partially clogged air filters (around 50% if memory serves). Sorry, I don't have any links to this study, but I'm not inventing this.<p>So, you are correct about there being some redundancy built into the airflow of a paper filter element. But the Transport Canada study revealed that there were sufficient blockages in the air filter elements of the vehicle tested to impair engine operation. This simply cannot occur with a K&N.<p>Regarding economics: a Peugeot 405 OEM air filter costs $50 CDN, and I would normally change mine every year. I often drive in dusty conditions. The car is 13 years old, you do the math.<p>As for particulates in the engine, the difference between a paper element and a K&N maintained in accordance with the manufacturer's recommendations is nominal. Most particles in the 1 to 5 micron range are unlikely to cause any damage to the combustion chamber or moving parts. For example, the carbon particles that adhere to valves, piston crowns and head, and are occasionally stirred up and sent out the exhaust are much larger and do not cause any appreciable damage. The only type of particulate that I am aware of that would be a problem would be volcanic ash. Further, the damage that a restricted air filter can do to an engine is significant.<p>By the way, it is absolutely untrue that all OEM parts are better than all aftermarket parts. It is simply naive to believe that manufacturers, even M-B, only fit the best available parts to their vehicles. Even a cursory understanding of economics will allow anyone to realise that the outsourced parts contracts (such as air filter elements) are often awarded to low bidders, as long as they are capable of meeting some minimum performance standard as defined by the manufacturer.<p>In any event, you and I are clearly not going to agree with each other on this. As a parting note, I would ask what type of oil filters and motor oil you use (and how frequently you change them). Not to mention tires. Among other components. I would imagine that your concern about air filter efficiency extends to other parts of the car.<p>;-><p>