I've replaced the original paper air filter of my MY98 by a K&N air filter.

Then someone told me that since the K&N filter are oil impregnated (are they?) they can damage the lambda sensor.

Any comments?

G.

 

It would seem that the airfilters giving problems with the AFM tend to be the oiled foam pad type. The K+N filter is constructed from a thin layer of cotton gause sandwiched between a couple of metal support grills. The oil impregnated into the K+N cotton is highly unlikely to go walkabout, unless it is over-oiled on cleaning. The K+N would be a safe bet.

Moray
(I have a K+N in my airbox, which is in the corner of the garage! )

 

PS: It's the Mass AirFlow meter (between the airbox and the turbo) that can be damaged by filter oil, the lambda sensor is stuck in the exhaust pipe!

 

Thank you Moray!
My doubts are clarified!

Regards,

Gustavo

 

Hi Gustavo,

I hope you understand that I was recommending the K+N as a good option, rather than some of the oiled-foam-sponge type filters which have been causing problems. I used one myself for a while on both my scoobies, never had any problems.

I did have problems with my previous car's HKS oiled-foam filter (Super Power Flow), but no problems with my blitz induction kit.

Regards,

Moray

 

No probs with my K&N. I do check it once a month though.

Thanks

Sonu

 

Moray,

Does this mean that there are problems with the HKS Induction kit system.... i'm running a Ramair filter at the moment on a MY98 and was thinking of switching to the HKS...

Any advice appreciated...

Jason

 

We know of 4 Air Mass Sensor failures, 3 were using oiled HKS cone filters and one using a Blitz stainless cone filter.

The only filter approved by Subaru UK is the Ramair panel filter, which is an oiled foam filter. Whilst these can leave oil residue in the bottom of the filter box, there are no known AMS failures resulting from their use.

That said, I prefer the polymer coated ITG or cotton guaze K&N panel filters and these are available from most good Scooby tuners. These are efficient, BUT provide the highest levels of dust filtration and have proved to be the most reliable. Both of these filters would meet the "equivalent design and quality" requirement of the Subaru Warranty Statement.

 

Pete,

Which model engine suffered the Blitz failure?

From what I understand, It seems that the latest engines (STI V etc) MAF unit (hot film rather than hot wire?) is more sensitive to filter problems.

Thanks,

Moray

 

Showing my ignorance here but the failure of the Air Mass Sensor.. how serious/expensive is this.. and i assume that you would know when this failed right ?