Cone filter gripes

[Tibbsey23]

Before I start I shall just clarify that my filter is not a cone filter, its cylindrical, but for ease I am going to call it a cone as it is essentially the same thing!



A couple of weeks ago I fitted a cone filter to my 940 as all but one clip was missing on the airbox and the filter was overdue a change. Also having read the article on turbobricks about intake restrictions. I figured that a cone would reduce airbox side restrictions, save sourcing an airbox and give me a reusable filter - so several birds with one stone!

I think the engine responds a little more quickly now, though having never ventured into the world of cone filters, I wasn’t really prepared for the extra noises the cone unleashes - some I really like, some I’m not so keen on. This is my first gripe - the sound of my CBV - Like a dump valve it makes quite a loud noise on gear changes - a bit chav for my tastes

My question here is - does it make so much noise because it is such a compact unit on the mitsi turbo and hence relieves the pressure through a very small diameter route? If this is the case, could it be silenced somewhat by fitting a bigger bore after market recirculating dump valve instead (to protect against the 2.4 causing the engine to run rich if air was simply dumped). Anyone got any experience on this front? would this however affect turbo spool-up as the blast of recalculated air wouldn’t be quite so concentrated?

Secondly - smell. Since fitting the filter I have noticed that upon opening the sunroof especially, the car fills with the smell of my crankcase ventilation system. Presumably this is because having less intake restrictions means that the vapour has an easier route to escape. My only guess is that the smell is travelling from the filter - through the large hole in the inner wing where cold air enters the area - back between the inner and outer wings and through the footwell vent that I thought was non existent on a 940 because of the ECU et al that is in its place. Anyone got any ideas, or any thoughts on how to cure this... should it even be a problem? Is my crankcase breathing heavier than normal? Should I block off this hole and route in an alternative cold air intake?

I know what the easy answer is to all this of course, but just looking at options! Another I have considered is that K&N offer a foam pre-filter, which i guess wouldn’t restrict the intake as much as the original set up and so I would probably still end up on top? Anyone have any experience of these and/or do you think it would help with any of the above issues?!

I know, man up...