I have set this 'friendly debate' up so we can have a discusion about air filters. There are sooo many different brands and styles and people have so many different opinions its time we discuss them.

Personally speaking from my experiance and my knowledge, I find the closed filter to be the best. I have a Pipercross Viper, that is made of carbon-fibre so it doesnt absorb heat on the casing. It gets direct cold air from my cold air feed that is in my headlight, air can only get in one way and that is forced in by the car being driven, so all air going in will be the air temperature outside the vehicle at X speed I am driving.

I also have experiance with K&N filters and find that they CAN breathe hot air from under-neath your bonnet (From different components) aswell as the major factor of the heat given off from the exhaust manifold. Cold air feeds do help with this and so does a Filter shield, basicly a sheet of metal to stop hot/warm air coming in contact with the filter.

Out of all the methods I have used my 2nd favorite is the standard panal filter. It utilises the OE airbox, something people are too quick to judge but manufactorers spend millions developing cars so they must know what there doing, performance-wise, to some extent.
Often the OE airbox does exactly what you want, plus it gives a 'non-tampered' look to the enginebay whilst gaining extra performance over the standard filter or a poorly fitted/located cone filter

What do you people think?
Agree or disagree - These arnt the only views out there

I've tried several set ups and I reckon the best way to go, performance wise, is to get a replacement panel filter like a Ramair which gives the most torque, not necessarily the most bhp though. I'm unsure whether it helps to drill the airbox or not. I've tried some which have been drilled but this seems to over fuel the engine and lose some top end performance on some cars.

Airboxes-Can be good,can be not so good,but can be made to be excellent if u have nouse. For instance. As standard my 1.8 Airbox had a pipe inside it so when the air enters the filter housing it is still got inches to go before it sees the element (this is restrictive) so what i have done is

Remove this wierd pipe
Remove and seal the vacuum box coming off the right of the airbox
Cut away the lower front corner of the airbox so it sucks air through there giving a)good noise b)zero resriction (it doesnt have to suck thru small hoses to get into the airbox)

Along with a K&N panel filter i think this is the second best way to increase power on an N/A car


Cones-On the right engine with the right placing of ducting these can be good and certainly look more sporty than an airbox. But cost more than a panel and cut box,and can let heat in unless u either completely encase it from the heat or blast it with loads of cold air so the tempurature is no hotter than the inside of a standard airbox.

Cones on turbos are more neccesary due to the amount of air it needs,a standard airbox may be too resrictive as the air cant get thru the hole in the box as fast as it can get thru a cone

Enclosed filters (CDA and vipers etc) By far the best way as its basically an airbox with a 100% cold air feed and its made of materials more resistant to heat than OE boxes, and the cone can let hot air in as the cooler will bring the temps back down anyway


Put a digital thermometer probe in the inlet pipe just after the MAF and try all 3 techniques and i bet the cone will give hotter inlet temps than the other 2 when standing,and more than likely to do the same at any speed unless ducted very well


Just my 2p and i will never use a cone on an N/A car again

Like i said i know someone who has got the best of both worlds. look

Damn you and your huuuge pic!
But even that can be question'd/made better

I PERSONALLY think I have the best set up I could possibly get, I have no hot/warm air getting into the engine just cold air from outside the car - What am getting at Cali is, as good an idea that is, it will still be breathing a certain amount of hot air thats trapped under the bonnet <---- Hence why bonnet vents etc are used

Thing is dazza. How does air get into that box,if those little hoels werent in the perspex the airbox is fed via a ram pipe that goes into the grille (on escorts this is the only way the airbox gets air)

The way to ensure only cold air can get at ur filter element is to create a sealed inlet to the airbox and ensure the airbox to throttle body pipe is airtight. However,the air may get heated somewhere between outside and the combustion chambers,a way to counter this is sheild these parts from the heat, by insulating them with something (IE/carbon,or metal insulation)

the picture i have showed you is a k&n in a standard calibra airbox. the perspex is only for show. i dont think the holes are needed but he like s them so......

Also he has done the same as scoop says cut the standard restrictive pipe of the bottom and got a cold air feed from the front bumper up to the box where the pipe was so its an enclosed cone with direct cold air feed.

Its a hell of a lot cheaper than an apollo or a viper kit and does the same job

i think its all down to how much air and how cold the air is,

ive got a cone filter on mine, and ran fine and got a good gain from it, but then i added a cold air feed, and it ran alot better etc, the cold air feed ran from in front of the front wheel, which was quite good,

but as i have got morettes now, i took one of the lenses out yesterday and made that into a cold air feed and its alot beter now, i would rather have it like this than a panle filter,