I've seen some pretty heated debates on forums as to whether to use the airbox or not in BEC's. It sounds like its a limitation of room dictating its use rather than power delivery or driveability.

Anyway, I've seen a few MKers with bulges and a pancake filter and was just curious as to how much of an affect it has on the fuelling and performance of the motor when it isn't drawing from a static body of air? (ie. an airbox)

Thanks for any help... 8)

Just deciding on some details for my build.

Chris

I can remember times when replacing airboxes with K&Ns caused no end of hasle getiing the carburation right on bikes so the same will apply, more so if fuel injection is used as the plenum creates a nice metering environment.

Something I think is that the people designing these high powered jap engines know a thing or two about airflow etc, however they may be set up to give particular characteristics i.e. flat spots at the noise measuring rpm etc

check my photo archive iv fitted the standard box turned round

Drew

Thanks for the useful reply guys.

Does using a free flowing filter in the airbox produce as much of a power gain as a pancake filter without the airbox?

Does anyone know roughly what sort of size main jet would be used for a pancake filter compared to an airbox and aftermarket free flowing filter? ie. Do they both produce the same ability to breath better; with the airbox just allowing the motor to draw from a static mass of air and probably reduce induction roar?

I'm more than likely going to use a carburetted R1 motor so any experience from others with the same motor would be great! sub2k - do you use an aftermarket filter? And if so did the carbs need to be rejetted to suit? Power gains?

Sorry for the Q's...

Chris

I used 4 airsocks on my 99 blade, and replaced the main jets with 132 jets and blocked off the pilot air holes in the carbs.
This is a method a BEC mate told me about and works well.
Apparently this is supposed to increase the power a little, and I have driven my car on track in both states of tune, and I think that it's the case. Mind you 2-3 hp either way isn't huge - unless you're racing!!
The main reason I did it was to get away without a bonnet bulge, which I have done.
there's pics on this thread. http://www.locostbuilders.co.uk/viewthread.php?tid=19228
There'll be pics of my air filters somewhere on my website (www button below).
Mind you I know nothing about pancakes!

Thanks for the info!

I'm thinking that I would like to have the bulge for aesthetic reasons... So I'm pretty sure I'll take subk2's advice and turn the standard box around and stick in a K&N free flow filter and jet the carbs to suit. Still I'm not sure whether I'll use a FI R1 or carbed... Still got a lot of research to do!

You website has been amongst around 5 that I downloaded fully to my PDA and read from start to finish during my breaks at work. Good job and I hope Lucy's still running well!

Chris

Winston,
Excellent, when I was building Lucy - and doing the research for it (again during breaks at work) - it was very encouraging to read other folks websites, Dodgy Roger, Donut,mk9r and Hellfire amongst others - that's the reason I did mine.
I don't believe I ever got the chance to thank the folks above - thanks guys.
I'm glad other folks are getting some use out mine.
All the best
Ali

Following your advice i've just tried fitting my airbox upside down and it fits. Only problem i can see is that it is now sucking air from within the engine bay. Do you guys think this is OK? See photo, but it is only about 5cms from the top of the gearbox to the face of the filter??
[img][/img]

Cheers Mike