Duratec Airbox and K&N Filter Upgrade

[Mike-360R]

Having recently completed my build I have carried out a few post-IVA upgrades including changing the standard panel filter for a K&N. I purchased the upgraded panel filter direct from Caterham but have found it doesn't really fit all that snugly into the standard S3 airbox supplied with the kit. To be honest, the original panel filter didn't fit great but the K&N seems to be fractionally bigger which means it's difficult to get the top and bottom halves of the air box to bolt together very neatly - so much so that I am concerned that unfiltered air could gain access through the gaps and find it's way through.

Has anyone else faced this issue? I have thought about trimming the edges of the filter to try and give the airbox a chance to close up more neatly and provide a better seal.

[K7 VCT]

The correct k & n filter fits perfectly or it should do....

[ChrisC]

I agree the fitment of the filter in the airbox is great, and the paper filter (from a fiesta I believe) is best.  The interesting thing is the same filter isn't used when swapped to a K&N, it's a Nissan I believe.   So check you have the correct filter, not the cross reference from the paper filter.