Question about air flow/induction

This is directly related to the drz but I assume the logic will apply to all carb'd bikes.

So Ive got an issue where relocating the battery is the most obvious solution. However this poses a new problem of where to relocate it too, the easiest of places is to fab up a battery tray which will intrude into the airbox. This isnt unheard and is often done in the drz world for a number of reasons along with quite a few other airbox mods which are very common on the drz.
However its gotten me thinking that as an even better solution, as opposed to butchering the OEM airbox I could perhaps change the current air box and filter housing for one of these:
http://www.ebay.co.uk/itm/CHROME-AIR-FI ... 1e6598e124

I know this is very likely to mean adjustments need to be made to the jetting (carb'd bike) but this isnt a problem as Im about to fit some flat slide carbs which will require jetting regardless.

So...
provided I adjust the jetting to suit am I going to have found a relative simple solution, or am I overlooking some very simple ERRORS!

[yorkie_chris]

What about using a new fangled lithium ferrous polymer battery like maviryk sells on svrider or a turntech from Zoran? Absolutely tiny, weigh nowt.

do they cost a fortune?

http://www.shoraipower.com/p-147-lfx09a2-bs12.aspx

It would be easier to hide than the stock battery, but would still need relocating
It does mean I'll have more space for a nice fuse distributer board though.

is it one of those cone air filters your looking at?

if so your looking at rejetting the carbs as a minimum and youll get heat soak from the engine i would have thought.

Carb Jetting isnt an issue, im fitting an FCR which will require jetting so thats already considered regardless.

Heat soak: A google brings up this - http://cjbfire.com/Heatsoak.pdf
I really doubt this would be a factor, no more so than it would otherwise be anyway. The modifications would take place away from the cylinderhead and for that matter the radiator.

[johnnyrod]

My experience of cone filters, and most people I've heard from, is that they're a pile of crap for the real world. I'd deffo try to keep the airbox (or most of it) even if it meant balancing the battery on my nuts while riding.

[Sid Squid]

Originally Posted by johnnyrod

My experience of cone filters, and most people I've heard from, is that they're a pile of crap for the real world. I'd deffo try to keep the airbox (or most of it) even if it meant balancing the battery on my nuts while riding.

Listen to this.

Lol understood

Is anyone able to explain the science behind the airbox to me? Is there an ideal void volume (I'd assumed individual to the engine) which should be maintained or is it the Enviroment which is key (ie static air).

*new questions are in relation to feasibility of partitioning off the air box to house electrics in one section but keep other portion as airbox using oem air filter.

[Sid Squid]

Very generally speaking the airbox of a modern engine will ideally be about seven times the swept cylinder volume of the engine as a minimum. This is the best compromise between big enough to work as a still air reservoir*, but not so big it will be difficult to find anywhere to fit it.

The airbox has a very specific function, it's not just there to hold the airfilter, it's there to provide the engine intake with a volume of air at as great a fraction of atmospheric pressure as is possible, (atmospheric pressure is roughly 1 bar, approx 14.5 psi, varying a bit with temperature and weather conditions).
As you will likely know a moving gas, (or liquid), exerts a lower pressure, and the faster it moves the lower the pressure it exerts, (hence the term 'static pressure'), the job of the airbox is to slow the air as it flows into the airbox such as to keep it's pressure as high as is possible, this means the pressure differential between intake and cylinder will be the greatest it can be, so that the cylinder will fill as best it can.
The measure of success, (or not, depending), of cylinder filling is referred to as volumetric efficiency.

Pod filters are the worst of both worlds - a physically small area for gas flow and out in the air rushing past the bike as you move, (remember that bit above about moving gas exerting a lower pressure?), compromising cylinder filling.

*Unsurprisingly it's never still in there, but stillness is the ideal - that would give the best VE.