Afternoon all

what airboxes are you all using and what db is your bec kicking out?

Modified Hayabusa airbox, tested at 97.8 db

Cheers, Nick

1/16" Ali air box/plenum feeding into intercooler then turbo, still whacked the meter at Goodwood to 107db which Isuspect was mostly general engine noise.

You need to fight hard to keep a BEC low when the engine and exhaust are close together, look towards soundproofing the engine compartment to the outside as well.

[Edited on 7/2/13 by mark chandler]

home made ally airbox with big cone filter was 102db at oulton but have changed from a k series race can to a zx12 can .
it is noticablly quieter but havent got it checked yet. if i was to guess i would say about 90 ish.

I'm running a standard Hayabusa airbox that I modified the cosmick way, not sure on induction levels but certainly a damn site quieter than open bodies with a foam filter.

Feel free to check out my photo archives, I think it's in it's own folder

We used the standard R1 airbox reversed
at IVA was 97Db

Running a fabricated Ali airbox with panel filter and a bit of ram air effect. It tripped the drive-by meters at Oulton at 108db - I think they're in the vale down by Knicerbrook/bottom of Clay Hill so was screaming it in third at that point, which is why I went over.

Only solution I had on the day was to line the airbox and underside of the bonnet (which seals the chamber) with air filter material and cover it in a protective mesh to stop it moving. It worked as I didn't get pulled again and was noticeably quieter from the outside according to people track side.

PiperX flat foam filter, 118db Next on my 2-buy list is a standard blade airbox (cheap) and hopefully mod it to fit under the Mk bonnet.

Cheers for the replies chaps. It seems the best way to keep noise down is keep the airbox standard?

Im doing Bedford in May and they dont give second chances for drive by noise so i need to get it right!

Homemade carbon fibre airbox (much better acousticaly than aluminium). Not sure of exact dB, but it is pretty quiet - certainly quieter than the last one I made for my old engine, which was 101dB.

If you can fit the original airbox, they are normally a quiet choice!

I flipped the standard airbox, keeping it to as near as standard as possible.
Although it has got a BMC air filter fitted

Description

When the airbox arrives i may have to flip/bodge it to fit. The problem i see in my head is the 2 roll bars getting in the way of the air box....The air box ive got fitted fits between these and is home made and incorporates a slight bit of ram air, which im told improves things a little at speed