Panel air filters and oil fouling - is it worth the risk?

[HDi fun]

You'll destory the cat if you constantly run over rich mixtures. You'll also wreck the cylinder bores as the excess fuel washes the oil film from the cylinder walls.

The key is getting more air into the engine first. Most fuel systems can cope with extra air ie. they're not maxxed out in normal tune and can deliver more fuel if necessary.

I'm not sure about the drop in panel filters to be honest - I don't like the idea of bathing the MAF in sticky oil.

[waynne]

IMHO turbo cars give the best tuning return and are usually over engineered.

HDI - the panel filters are fine. You only have trouble with oil if you soak them - all it needs is a fine mist. I know a few people who run them dry and they still work well. I've had mine on since I got the car and the MAF shows NO signs of oil fouling - I give it a very light spray on the downward side. The oil is just to aid filtration but most are equal or better than standard paper filters even without the oil.

So to summarise the most power on a Turbo comes from a REMAP and on a NASP engine I would say fast road cams make the biggest difference.

[pgarner]

i was looking towards the "green" filters as i dont think they require oil.

[HDi fun]

Do they really make that much difference? I get the OEM paper/foam ones for about three quid so I just change it every couple of months. Would an ITG filter be better?

[waynne]

To illustrate the difference if you put your hand behind a paper filter and blow on it you will not feel a thing.

On a foam panel air filter you will feel your breath through the filter on your hand. It does not create the low down drop in power associated with induction kits and it doesn't make as much noise.

I see it as a win/win. Plus it is washable so after 7-12 paper filters it will have paid for itself.

[HDi fun]

Do they filter as efficiently as a std one?

[waynne]

Hmm, a layer of foam against a layer of paper. I would say the paper filter has to be better but to the point of pedantism. It is this over filtration that is sapping your power.

The foam filters will filter out the smallest particles and because they are layered this stops them clogging up so quickly. Paper filters can probably last longer without needing a cleanout/replacement.

[pgarner]

Are the really small dust particles going to do much harm to your engine ? i would have thought the combustion tempreture would fry the dust

[HDi fun]

I dunno - I know what turbochargers cost to replace so I want mine to breathe the cleanest air possible. I am a bit of a pedant when it comes to such things. Hence the reason I use filter magnets etc. But then my cars run to ridiculous mileage without engine problems. Which isn' to say they wouldn't if I used a ITG or K&N filter. I ust haven't tried yet

[waynne]

K&N state their filters are at least 99% efficient as the OEM paper ones. Cotton filters are the best compromise apparently.

[HDi fun]

I'm sticking to my guns for now. Even if K&N can back up this claim with real world test data I really don't want that 1% passing the filter. Surely it must be the smallest particles that go through. Over time, mixed in with the engine oil it's likely to become abrasive and damaging to parts that never come into contact with the intake air.

So you could find yourself with excess wear in the bottom end bearings which no-one would ever attribute to being caused or exacerbated by the use of a free flow air filter.

Periodic oil sampling might be a way to monitor this, perhaps proving that my pedantic approach to this whole subject is unfounded.