Oiled air filters

Not at all. I've used K&N filters on bikes for years and can honestly say I've never had a problem at all, as long as you don't over-oil it!! If you use too much oil, you'll know right away because your car/bike/whatever will run way too rich.
 
Thanks for the response.

The reason I asked is that my son's car failed smog inspection with the NOX reading too high at 1600 rpms but okay at 2500 rpms. He has an aftermarket smog legal supercharger on an injected motor but is using an oiled air filter. He's going to try and use a regular paper air filter next.
 
On newer cars I heard that the oil can contaminate the sensors on the computer cars. I think K+N has oil and intructions to lightly oil the filters to avoid this issue.

One of my friends was told by the dealer that if he used an oiled K&N air filter on his truck, the new truck warranty would be voided.

My son cleaned and re-oiled the filter and will try the smog test later this week. He thinks now that he let the catalytic converters cool down too much before the sniff test.
 
Might try not oiling until after the test. The sensors may be covered in oil and need cleaning or replaced. I was watching a show about k+n filters and they mentioned some thing about that problem. I think they reformulated the oil the avoid contamination and instruct to lightly oil the filter. I don't know a lot about computer cars, other than it doesn't take much to goof up the signal to the ecu and make the car run like crap. Thats why the dealer voids the warranty.
 
Might try not oiling until after the test. The sensors may be covered in oil and need cleaning or replaced. I was watching a show about k+n filters and they mentioned some thing about that problem. I think they reformulated the oil the avoid contamination and instruct to lightly oil the filter. I don't know a lot about computer cars, other than it doesn't take much to goof up the signal to the ecu and make the car run like crap. Thats why the dealer voids the warranty.

It's not a K&N air filter, but similar type. He did check the throttle body and it was clean. I did suggest that he clean and not re-oil it till after the test, but you know kids. Sometimes they just won't listen. :shrug:

BTW, it's not a Ford. Its a (cough) Acura NSX.
 
It passed the smog test yesterday. My son cleaned and re-oiled the air filter and let the catalytic converters warm up. He thinks though, that the real reason it passed was that the second tester left the car in first gear instead of third on the rollers. :shrug: