When service time comes around again, is it worth switching to a K&N, Green or Pipercross panel filter, or is the stock Honda element just as good?

I'll get a CAI in time (I know there's no performance gain, but if it sounds good and improves hot weather kangarooing I'm happy to invest), but suspension mods are higher up the agenda just now.........

Any advice welcome as ever......

 

Hi FB.

If the K&N is about the same price or a couple of quid more, I would go with that. Filtering is their bread and butter and quality is top.

But the OEM isn't any form of restriction so you aren't missing out much if you do go that way.

 

Well its not a panel filter its a cone

K&N, i would go for. I dont like the foam because of the way it holds dirt and could cause issues clogging other bits up (possibly MAP sensor).

The reason i would go for the k&n is: you can clean it, k&n make good stuff IMO and they are about

 

I could be wrong here... but even the stock item is a cone not a panel filter.

Personally if your wanting to get some cost effective intake mods. Get a 2nd hand k&n and reoil it, tops 30 quid there, gut the airbox, and then get a spoon copy snorkle for about 90 quid.

Cool intake, bareable sound levels, maybe a couple of ponies freed.

Everyones happy

 

Tis a cone indeed.

 

Thanks folks.

I guess the website I was looking at was using "panel filter" as a generic term for replacement elements, but thanks for setting me straight anyway........

Cheers.

 

I seem to remember a thread comparing the standard cone to an aftermarket one. It had some pics of the filter with the element removed showing the design of the interiour. IIRC the Honda was a very smooth aerodynamic shape which provided a lovely clean flow of air, but the aftermarket (sorry can't remember the brand) was a pretty shoddy design. I have had a quick search but can't find it yet, I'll keep looking.

 

that was me and heres the pics

the black is K&N and the white Honda OEM, for my money i would go for the Honda and change it more often than Honda recomend, or do as i did and bond a K&N filter to an OEM connector best of both worlds, the K&N part in the picture is what i cut off the filter, what was left was bonded onto the white back plate.


I had the bits and the time but not sure if its worth it but its probably the best filter you can get, its as good if not better than oem for filtration, washable and no foam bits to worry about.
the rough edge on the inside of the K&N is how it was when i opened the filter, this is very bad and not what i expected from a top end filter.

 

Yes, theoreticall, but in practice, the sort of roughness that you are talking about makes little odds!

Dependant on Laminar/turbulent flow, frictional losses are a factor of the term f, calculated as follows:

Laminar flow is at Re<2000
Turbulent is at Re>3000

Laminar Flow f=64/Re
Turbulent Flow f is found from a graph, such as the moody chart on this page http://www.efunda.com/formulae/fluids/calc...iction.cfm#calc

Re = (QD)/(vA)

Where:

Q is Volumetric Flow rate, 0.15m^3/s (2L engine, 9,000rpm)
D is Diameter of Pipe, ~2.5" or 0.0635m
v is Kinematic Viscosity, ~12.8x10^-6 m^2/s
A is cross sectional Area of pipe, ~0.03167 m^2

Therefore, in our application,

Re = (0.15 * 0.0635) / (0.0000128 * 0.03167)

= 0.009525 / 0.000000405376

= 23496.704

Therefore, our flow is the transition region between Laminar and Tubulent.

The additional surface roughness will cause some additional tuerbulence in the flow, but you're pretty much there already.

If you look at the smoothness (or otherwise) of the rest of the intake tract (size of nobbles Vs diam of pipe) then this component will not make a significant difference.

What is more important is the bell-mouth shape of the Honda part. This will ensure that air is drawn in from even the widest part of the cone, whereas the K&N unit will probably not be as efficient in this region. That said, the more free-flowing K&N filter material will probably compensate for this...

Happy to answer all your (easy) aerodynamic questions. Difficult questions may require donations to purchase all those text books I flogged in the 2nd year and/or some good fluid modelling software....

 

and i thought i had too much time on my hands
all i know (and it may be not much) is a bellmouth design is better than a rough pipe end, it actually flows more at a given vacuum, how much is up for debate but it is more.