73911

Here's an article I wrote about air filters.



Richard Newton

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.

Mondrian

Quote "...A 10-inch diameter filter that’s 2-inches tall will flow more air than a 5-inch diameter filter that is 4-inches tall..."

Why? If both filters offer same media with same surface area & efficiency the volume of air going through the filter should be the same unless restricted by intake!

73911

Mondrian - That makes sense to me. Not to the people who make the filters though.

My column is limited to 800 words. Sometimes I just can't cover everything in that space. I try though.

Richard Newton

Jherriott

If you put a piece of 2" thick foam over your mouth and inhale, then do the same with a piece of 5" thick foam... You will understand

Mondrian

What length & width?

Jherriott

LOL! I'm not touching that with a 10' piece of foam! :P

Mondrian

Really appreciative of sharing the article but personally I wished for more quality content in those 800 words. As steve pointed out no mention of downside when switching from OEM filters to performance/race filters!

As an example I'd like to know how additional air flow volume is achieved, via an increase in filter media surface area or reduction in filter efficiency or both.

73911

One thing to consider about flow rates is that they only become critical at WOT. You seldom use WOT on the street. Folks on another forum pointed that out.

The reality is that for most of us the OEM filter may be the best filter. Here's a link to some work the folks on the Nissan forum did.

Richard Newton

Mondrian

Exactly. Most see filter as the cheapest route to performance gain or the finishing touch to that 20k rebuilt but as the Nissan article says .... " Compared to the AC, the K&N “plugged up” nearly 3 times faster, passed 18 times more dirt and captured 37% less dirt."

Reiver

That's my experience. Tried one on my SBC Hot Rod 4 barrel and kept plugging my idle jets with dust/dirt. Went to a paper/stock filter and never another issue.
I get the heebie jeebies when I see one 'oiled' on a Porsche.