Last year my civic failed the missions by a mile, so they put some fuel cleaner stuff through it and it passed ok.

So roll on this years MOT, it failed again on emissions, so he took off the filter for some reason and he said not only does it pick up better but it passed the emission test with a perfect number? is it a coincidence or could the cone filter really be the problem?

Ill be getting a standard airbox for sure, especially if it makes the car run better

 

As most test's on air filters has proved a standard / modded air box gives getter performance than most aftermarket filters.

Joe

 

Don't see why it should, unless it is excessively blocked by dirt and crap. But a modern ecu should be able to control it fine anyway...

 

God knows then, the car passed the MOT anyway

 

Im a tester and have had a induction kit on all my cars and theyve never failed an emissions test. It should have no effect on the emissions at all unless as said its blocked but id of thought it would be noticable driving it

 

not if its happend over a year slowly loseing power

get new filter or clean out your one

 

Crap.
tabetha

 

missing the issue
tabetha

 

think about it!!
tabetha

 

Fact is cone air filters can help performance, virtually none have any downsides.
Giving better performance is NOT the same as passing a MOT, the difference is the speed of the car, at mot time it is stood still sucking in all that nice hot air, this WILL RAISE THE emissions simple as that, going along the road the hot air is draughted out the engine bay area and not ingested, unless it is one of the really badly designed cone filters.
Put a cone filter on a cossie for example and take emissions readings without and with the fan on, I can guarantee you having seen this loads the emissions(CO) will rise, due to the hotter air containing less oxygen.
My own cossie does this, so I just wait for the fan to come on then stop, then take readings.
As I have a temperature probe in my air filter end(so not in direct flow)I know the temp of the air filter air, and also inlet air in plenum(another probe), having used this(2 probes) with both air box and cone filter(with NO heat deflector), the perceived "hot" area on a cossie at least behind the drivers light where the airbox/cone filter is is NOT a hot area, remaining for 99% of the time within around 2C of ambient, from 30mph upwards.
Just my observations, both probes were zeroed on my temp gauge, down to less than 1/10C, and the gauge reads down to 1/10C.
tabetha
tabetha

 

it depends on the car, location of filter, type (open cone/enclosed/shielded) and general condition.

focus's for instance don't like open cones possitioned where the air box is (even with shielding and a cold air feed) as they just suck up all the hot air in the engine bay. i've known at least one 1.6 focus to fail emmisions with an open cone on and passwith flying colours once swapped for standard air box and pannel filter.

 

well it must be the cone because he said it failed badly with it on, and when it was off it passed with a healthy engine reading.

Its open cone, you can see the mesh and the filter under it, and its dark red, whether or not thats because its so dirty, or it started off dark red im not sure, but ill definitely look into changing it

 

Totally. There simply isn't one rule that works for all cars.

We did a test with an ST200 and at idle, medium, and fast cruise the inlet temps were all 'up' on a cone filter compared to a shielded cone, and the standard airbox.

In a car with better air flow around the engine, or more direct ducting to the filter, then I'm sure this would be different.

Never heard of a car failing on emissions because of a cone however??

 

If it's sucking in hot air with a cone and failing then removing it will just allow it to suck the hot air in easier so thats not right.
If it were blocked the ECU would see less air/map and only fuel for whats there, unless your running carbs and it sucks more fuel in as a result of being blocked (like having a choke on).

Strange one...

 

In one off fast ford or performance ford they did a test on filters with the mk2 focus Rs with aftermarket kits. And the modded standard box was the best irc. They where inclosed system i no.

Joe

 

i think you may be missing something mate. when we say remove the cone filter we mean refit the standard air box and air feed.