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[RivRaptor]

the filter has 25% more surface area, no flow or capacity.  it is the same diameter, only 1/2'' longer so your old oil filter wrenches will still work.
[/quote]

"The increased media supports the higher flow rate of M8 engines" Quote from Service bulletin and 25% more surface area is by definition more capacity. So I stand by my statement.

[skratch]

no, more surface area does not equal more capacity.  it just means that there is more filter media in the can.  obviously, a longer can is going to equal more capacity, i'm just saying that 1/2'' longer can is not equal to 25% more capacity.

[grc]

no, more surface area does not equal more capacity.  it just means that there is more filter media in the can.  obviously, a longer can is going to equal more capacity, i'm just saying that 1/2'' longer can is not equal to 25% more capacity.

Exactly! 

Adding a half inch to the length of the canister and stuffing it with 25% more filter media is not the same thing as increasing the fluid capacity of the filter by 25%.  Assuming the filter measured 2.75" in diameter, the canister would now measure 4.0" long and 2.75" in diameter versus the original 3.5" long and 2.75" in diameter.  That would increase the actual volume of the canister about 14.2%.  That's before they stuffed 25% more filtration material into the canister, reducing the actual fluid volume capacity by the added volume of the media. 

Volume of a cylinder =  [pi x r²] x height (length)
pi = 3.14   r = 1.375"  r² = 1.89"    h = 3.5" or 4.0"
Old canister = [3.14 x 1.89in²] x 3.5 in = 20.77in³     
New canister = [3.14 x 1.89in²] x 4.0 in = 23.74in³
23.74 / 20.77 = 1.142         14.2% increase

Jerry

btw, since the diameter didn't change, it doesn't really matter what dimension I used for the diameter.  You can get the same result just dividing the new length by the old length, 4.0 / 3.5 = 1.142 = 14.2% increase.  Thought it would be best to show the whole formula for those who care about details.

[RivRaptor]

"EFFECTIVE media surface area was increased by 25%.....increased media supports the higher FLOW rate of MKE-8 engines"  Quote from service bulletin.  EXACTLY.   Larger filter holds more capacity.  No one is talking in absolutes, better yet lets calculate some numbers that will be helpful or better yet if your gonna add calculations you should at least include only the filter media portion of the equation not the whole filter can structure.

[Twolanerider]

Exactly! 

Adding a half inch to the length of the canister and stuffing it with 25% more filter media is not the same thing as increasing the fluid capacity of the filter by 25%.  Assuming the filter measured 2.75" in diameter, the canister would now measure 4.0" long and 2.75" in diameter versus the original 3.5" long and 2.75" in diameter.  That would increase the actual volume of the canister about 14.2%.  That's before they stuffed 25% more filtration material into the canister, reducing the actual fluid volume capacity by the added volume of the media. 

Volume of a cylinder =  [pi x r²] x height (length)
pi = 3.14   r = 1.375"  r² = 1.89"    h = 3.5" or 4.0"
Old canister = [3.14 x 1.89in²] x 3.5 in = 20.77in³     
New canister = [3.14 x 1.89in²] x 4.0 in = 23.74in³
23.74 / 20.77 = 1.142         14.2% increase

Jerry

I'm not defending HD's often questionable arithmetic skills Jerry.  Just to play Devil's Advocate it's worth considering that calculating only total volume of the cylinder wouldn't absolutely vitiate their claim though.  They could be right one of two ways:

1) If inside that larger volume they also used a different media, and that media's properties were such that more surface area of media could be installed in a comparable space compared to the old media, than a volume increase of less than 25% could still allow for a media surface area increase of 25%.  For the math to work it would require both the volumetric and the media changes and I've read nothing that suggests a media change.  But it's at least possible.

2) This is more likely.  They are saying 25% more surface area and not 25% greater volume. With all the overlain folds, weaves, pleats, etc of a media surface an approximate 14% greater volume could equate to filter surface medium increase of more than 14%.  Especially if part of that initial smaller volume was occupied by mounting protrusion, bypass, etc. 

It's always easy to doubt Mother Harley's "robust" claims.  But they might not be as far off on this as the initial calculations suggest.  Just for grins I just fired up SolidWorks and drew up cylinders of each size, gave away a randomly chosen 5% of internal space of the smaller cylinder to each to WAG estimate whatever is lost where it mates to the engine, then filled it with a WIX nothing-special template I found to estimate a media.  With that (yes, the damn Coronavirus at home time has me THAT BORED) done I got a 22.7% increase of surface area for the media within the only 14% larger overall volume.

I am SO embarrassed to realize I was that bored.  Close to 40 minutes of my life I'll never get back just to see what life is like inside of a Harley Davidson oil filter THAT ONLY FITS BIKES I DON'T EVEN OWN !!  I am such a f^(*&ing dweeb.  Screw this.  I'm taking all my clothes off then wearing only sneakers I'm going out in the garage to sit on the Road King and make vroom vroom noises in the dark.