Air Filter Comparison|
Courtesy of: Mance Etheredge
I managed to pick up 4 air filters today. Below are the names and physical specifications of each. All of the elements use pleats that are EXACTLY 7.875" wide.
Ok K&N/oiled gauze filter owners, here's
where it gets ugly...|
Pic 2: My kitchen light...|
Hey don't shoot me I didn't pick it. Just got lucky with the home purchase I guess.
Pic 3: My kitchen light thru the K&N...|
Audi air filter is now listed in "Air
and the plot thickens...
Weird! Box says "Audi/made in Slovenia." Mahle says made in Germany while MANN says made in Austria. Sealing material is same color, consistency as the MAHLE filter but thicker, tighter fit as the MANN. Paper element is identical appearing to MANN but closer pleat-count to MAHLE at 89. Adhesive strip is top & bottom in the same amounts, ie; 1-top/4-bottom as MANN.
Biggest surprise is the pleat count is 9 less than the MANN and only 1 more than the MAHLE. Be interesting to see the differences in flow rates as the Audi paper element is easier to blow thru with breath pressure than all except K&N yet is identical color/thickness as MANN.
Also makes me wonder if even with the greater surface area of the MANN that the fewer pleats and easier "blow-thru" might favor the Audi. Maybe 98 pleats is too densely packed?
Are MANN/MAHLE in cahoots? Maybe a MANLE filter? "MANLE yes, but I like it too" in my best Irish brogue.
Keeps gettin interestinger and interestinger ;-)
Air filter flow testing...|
This turned out to be easier than I thought. All of the air filters except the K&N were self-sealing under vacuum. I just sat them upside down, centered over the flow bench inlet and the vacuum would pull them flat and seal them against the bench top. The K&N required a small bead of silicone around it's rubber sealing edge and a big dictionary (true!) placed on it til the silicone cured to seal it as it's rubber is less compliant/resiliant than the type used on the others.
Testing started at 280CFM and was slowly cranked up until first depression was noted. Then the process was repeated 3 times for each filter and their numbers averaged.
While the K&N is "very slightly" used it has been cleaned per manufacturer's instructions with their cleaning/recharging kit. Then excess oil wicked out with paper towels pressed tightly into pleats on both sides overnight.
In order of best-to-worst:
K&N: 732CFM (521 miles)
AUDI: 728CFM (0 miles)
MANN:678CFM (0 miles)
MAHLE: 662CFM (0 miles)
FRAM: 622CFM (0 miles)
PUROLATOR: 618CFM (0 miles)
Bear in mind these numbers are pure "flow"... nothing more, nothing less. They don't address or speak to any pressure differentials once mounted in the airbox tho they are a very accurate representation of what I'll find once I get to that aspect of testing which could take weeks to conclude as it's done with repetitive 2nd gear-to-100 mph road-tests. And I have to drive 22 miles out in the country-side to do them comfortably.