They're both quality air cleaners. The K&N flows a little better, 270 cfm for the K&N and 255 cfm for the Ness.

 

And considering a 96 cu. in. engine at 6500 rpm only needs 150-180 cfm, one would never notice a difference.
Even the stock filter, if kept reasonably clean, flows more air than the engine will ever use- I think I read somewhere that it flows 210-220 cfm...

 

48inÂł × 1/revolution × 6000revolutions/minute = 288000inÂł/minute (á 1728inÂł/ftÂł = 167ftÂł/minute)

167ftÂł/minute on average at 6000 rpm (6500 rpm = 180ftÂł/minute). The instantaneous velocities are a bit higher, I'd imagine, but don't feel like doing the math...

 

A&N Big Sucker and think about the Vance&Hines FuelPak for fuel management.

 

glens.... I have one question.

Huh?

 

Piston displacement in cubic inches, times the number of such occurrences per engine revolution, times the number of such of those occurrences per minute, converted to cubic feet.

At 6000 RPM it amounts to 167 cubic feet of air pumped (disregarding losses due to inefficiencies).

The piston starts its way down from a dead stop and accelerates until it's halfway down when it starts to decelerate again before coming to a stop at the bottom. On average it will move as much air as it displaces but the velocity of the air will not be constant since the piston speed is not constant. It will be not moving at first, then pick up speed, then slow back down to nothing eventually (per cylinder intake cycle).

The mass of the air itself will also cause a delay in both the starting and stopping, so those events won't coincide precisely with the piston motions. (plus there are obstructions to the flow within the intake tract itself and these obstructions cause further delay, but I digress) At its peak flow rate the air will be moving faster than it would if at a steady state of flow the whole time.

Think about it. If at the end of a crank cycle 48 cubic inches of air flowed past the filter, but it actually only moved during 1/2 of that time, then the velocity while it was flowing would be twice as fast as it would have been if that same amount had steadily flowed over the whole timeframe. Get it?

So the peak flow rate was actually closer to double (maybe a lot more), but only for half the time (maybe a lot less). It all averages out and those values aren't exactly right, but for purposes of example they'll suffice.

So for moving 200 cubic feet of air per minute and not have any impediment from the filter assembly at any time while doing it, you'd really need a filter assembly that could readily flow at a higher rate than the average amount it sees spread out over time.

Way too simply explained (in that it leaves a lot of factors out), but I hope you get the picture.

Think of it like transporting a half-pound of copper-jacketed lead to a hillside 100 yards away over the course of 1 minute. You could carry it all at once at a fairly slow pace, or you could send it a couple hundred grains at a time at a very high velocity for each piece. The "flow" rate of the lead would be the same on average, but for the second method each piece would be "flowing" quite rapidly.

Maybe that doesn't help illustrate it any, but it was kind of fun

Still here? Hahaha. Okay, so say I develop a filter assembly and hook it up to a blower. I'd previously measured the amperage on the motor driving the blower while it was moving 200 cfm without the filter. Then I measured the amperage on the motor while drawing through the filter assembly. It was the same, so I can safely say the filter assembly flows 200 cfm. If I up the motor speed to 225 cfm and it draws more power going through the filter than it does without it I can't say my filter assembly flows 225 cfm. Say the amperage starts to diverge at 215 cfm. That's the flow limit of my filter.

I get a sneaking suspicion that's how these things are rated. But as we've seen, (too simplistically,) the flow rating of my filter on a v-twin engine will be less than that if at every point in time it's got to be "invisible" to the engine.

What a fun way to kill time, h'uh?

One other thing I thought I'd mention (thought of it while reading it over before posting it). Remember where the piston is at a dead stop, accelerates to the midpoint of the stroke, then slows down to nothing again? The longer the stroke, the greater the variations in speed. You probably already knew that, so just call me "Mr. Obvious" :-) At any rate (pun intended), all else equal, a larger-bore shorter-stroke engine would be "easier" on the filter assembly since the peaks wouldn't be so great, right?

We didn't even get into what happens

 

Wow Glens, that was quite a mouth full, LOL. I have to admit, I got about half of that, but I was intrigued. LOL

One time I asked a buddy of mine why the sky was blue. We use to ask questions like this, just to see the answers the other came up with. He came back with a email twice as long as your post. LOL I checked out what he had wrote, and he, of course was right. My buddy is one of those guys. Smartest man I know (he got a perfect score on his ACT test back in HS). He has two degrees in History, and works at a call center, LOL. like me, he is just lazy, and has no drive to succeed in business.

Oh well, still a good read. LOL

 

I thought The filter that comes on the big sucker was a k&n.

 

Another ANBS here, used on my last two bikes. No oil leaks from the filter with the ANBS, any small amounts from the breather get directed into the intake and through the combustion chamber.


As a footnote dont bother with the ANBS stage two unless you have a big motor. The filter sticks out further and effects comfort for no gains.

 

The filter element in the ANBS is not a K&N.