How big does the airfilter need to be ?

[sharky]

I'm building an airbox and wondering if a 150x150mm K&N panel filter would be big enough ? This gives approx 225cm sq area (not counting the pleats)
Is it poss to have to big a filter area in the 'box ?

There is going to be plenty of air fed into it so that won't be a problem.

[fimpBIKES]

what area does the standard filter set-up have?

also, remember that filter area is measured across the whole zig-zaggy length on the filter surface


give us more details on the airbox building mate, sounds interesting!

[sharky]

Stock filter
http://www.streetfighters.com.au/forum/upload/46500308922355.jpg


http://www.streetfighters.com.au/forum/upload/46500308926514.jpg

Area of opening 120cm sq. Compared to the 225cm sq of the 150mm sq K&N.
So even though the filter area is slightly larger it actually goes through a smaller hole, whereas the 150mm sq filter is obviously bigger.
I might be able to work something to use the K&N stock filter but is it worth it ?

http://www.streetfighters.com.au/forum/upload/46500308916903.jpg

Ali box ready for local welder. Made a wood mock up first.

http://www.streetfighters.com.au/forum/upload/46500308919632.jpg


150mm sq cake tin from ebay $10.00 inc p&p.

[fimpBIKES]

what are the differences in thickness of the 2 filter panels (i.e. how deep each zig-zag is)

[sharky]

The K&N FJ1200 filter is deeper than the 150mm sq one.

[fimpBIKES]

meh, just go for it

im thinking it'll be fine

[Large]

Looks like the stock airfilter should be measured around the curve too, which would prolly make it more than double the size of the old one, so might be a bit restrictive.

Which would only be a problem with a Suzuki

:D

[sharky]

I was finking about that......
The question mark is over the actual hole in the back of the stock/k&n filter.
Doesn't matter how much air flow/filter material if the hole it has to go through after is smaller suuuurely ????

[Large]

Don't know that one. A hole is just a hole, but a filter is restrictive, which I think is why there's so much surface area.

[Issues]

air usage is 2.5CFM/HP so 100hp needs 250cfm flow through filter. K&N should state a flow rate on the filter.
Good luck with it.
Cheers issues.

[sharky]

Found a K&N fj12 filter and airbox in the states for US$20 buy it now.
Only getting the filter sent over.....for that price I'll make it fit. :D