73911

Here's an article I wrote that's all about air filters.



Richard Newton

nine9six

I would NEVER consider putting a POS K&N filter in anything; and their no comment on the filtering capabilities bares out which has already been proven by independent test results. OEM, Mahle, or BCM if you dont mind shelling out $100+ on a reuseable air filter.

,,,and thats all I have to say about that.
FG

EMBPilot

right?! lost all creditably the moment i scrolled down and saw the K&N

i was trying to refrain from responding to another case of blog garbage. he has unearthed such a mountain of new information regarding air filters.

Steve Weiner-Rennsport Systems

Whats lacking in the article is the distinction between the filtration requirements for street engines that should last 200K and for race engines which should last anywhere from 25 to 200 hours.

BIG difference.

73911

Steve - I need to start a feature article on air filters. Everything about our cars is so complex.

K&N has a huge advertising budget. They dominate the market and intimidate the magazines.

I'm lucky that Vintage Motorsport magazine is one of the few magazines left that is reader orientated.

Richard Newton

Quadcammer

not really

Cemoto

In my book, our cars are sophisticated, but not entirely complex.

pp000830

One of the problems of debating air filter quality in most Rennlist discussions is that they lack any quantitative data as to actual impact on engine component service life of using x brand filter that lets through x micron size particulates vs. y branded filter that lets in y micron size particles. Also a measure of pressure drop across differing filter brands would need to be discussed. I suspect the pressure drop, efficiency of a filter is inversely proportional to effectiveness - particulate catching ability for a given filter surface area. I also suspect beyond a certain area size increase the pressure drop becomes negligible.

One could put a sensitive vacuum guage just past the filter housing and see what the preassure drop is for various filter brands and designs.

Andy

OverBoosted28

I understand why a lot frown upon K&N use, but most miss use these filters. New they need to sit unpackaged for a bit. Usually on some paper towels to soak up excess. When u clean and re-oil, need to do it in very light, repeated coats, over a day or so. Again, let it sit and soak up excess. Have never had any problem (no MAF contamination) with any of their filters, when using this method.

AOW162435

I tear into my 993 as happily as I do my other cars and find it no more complex than any other mechanical item placed in front of me.



Andreas

EMBPilot

(Not directed at you OB)
Who has time for this, for what in return, some fake "gains"? + added risk.

Install proper OE filter, done. No blog or magazine needed.

OverBoosted28

That's why I stated that many don't like the re-useable kits. Just my experience, that it's been fine and (not necessarily on my TT) I have found slight gains in performance.

KNS

While I don't like the idea of possibly messing with my MAF and I'm perfectly happy sticking with a factory style paper element, K&N style filters can be effective if used properly.

On the helicopter I fly (AS350B3) we use a washable, oiled filter much like a K&N type filter. Of course there is no sensitive MAF type sensor between the filter and engine inlet. I can't imagine the certification process that those filters went through to be approved for fitment to a turbine helicopter.

Steve Weiner-Rennsport Systems

Yessir!

You are so right about that!!!

Steve Weiner-Rennsport Systems

Andy,

I've done a LOT of engine dyno testing & development for the past 41 years and its easy to see differences between air filter elements (oiled-gauze & foam) and various paper ones. With a dyno resolution of 2 BHP, we can certainly measure small changes.

Air cleaner designs are a totally different subject.

I've never seen ANY power differences between a new OEM paper element (Mahle, Mann, Purolator) in 911 engines and their oiled gauze replacements such as K&N and BMC. None.

Now, the oiled gauze ones flow more air when they get dirty compared to paper ones so there are measurable gains in this case.

For me, simply keeping a fresh paper element in there to maintain best performance is preferable to the oiled gauze ones since the latter ones do not protect the innards of the engine as well from abrasive contamination.

Foam and oiled gauze is just fine for racing engines where there are no long-term engine longevity expectations. In those cases, there are no paper options so we use whats available and what will fit the intake system in use.