Originally Posted by TiGeo
Originally Posted by CleverUserName
Originally Posted by TiGeo
Originally Posted by CleverUserName
It's the oil from the filter.
It gets on the MAF and causes the DPF to get plugged. It's common on VW TDIs and requires the DPF and MAF to be replaced. All because of an oiled high flow air filter.
The irony is that increasing airflow won't do anything on a diesel without a supporting tune.
I suggest that it doesn't come off the filters, even at flows that are well beyond what the engine can do and even at oiling levels that are egregious. It's BS/urban legend. I remember having 2 MAFs go on my old Jetta, I'm sure if I had been using a K&N it would been blamed. I'm sure if I sent the MAFs to K&N they would have tested them and found no trace of their oil. MAFs actually fail sometimes and K&Ns are an easy blame based on the propagation that the oil magically flies off. Runnign them in all my cars with zero issue/drama and have been for years. Anyway, some great videos on the subject.
https://youtu.be/LeqP_1Y_pC0
https://youtu.be/gE6moItrZNg
The negative effects of oiled high flow air filters is well documented. Not BS or legend.
http://forums.tdiclub.com/showthread.php?t=290373
Read through it all. Seems to be a discussion primarily about the worthlessness of these filters and/or CAIs on the TDI engines of course with a smattering of "K&N oil will foul your MAF" chants. No evidenced or quantitative data that I saw to show that MAF issues were from K&N oil (maybe I missed that?). Not super familiar with the TDIs but is it possible there is some oily/combustion gas mixture that gets re-digested through the intake track that could also be to blame? I will stand by my comment - I've used these things for a long time with no drama. I don't use a CAI but just the drop-in panel filter. One owner that had issues said something to the effect that his cone filter on his CAI kept coming off every few weeks...I'd say that was more of his issue than the filter. I have done multiple UOAs on my cars with K&Ns (posted here) that continue to show normal levels of SiO2 and insolubles and excellent filtering. One poster in that thread basically said "if you run K&N you will absolutely have higher levels of SiO2 in your oil"...how don't I? I have no visible dirt/grit/grim on my intake hoses. My current Atlas has a MAF with no drama after 2 years/22K miles (my Golf doesn't have a MAF). How is this possible? It's possible b/c I 1) operate in low-dust/normal daily driving conditions 2) take care of my cars including following K&N's instructions on their cleaning/re-oiling procedures (once every 50K with a shake out of the larger crap/leaves/bugs every year). I think K&N filters are fine. I also like the dry-flow filters by aFe. I want to see direct data showing that K&N oil is why the MAF failed vs. other culprits. They 100% filter less than a paper filter. How much less? That famous report (Spicer?) that makes the rounds every once in a while shows the K&N to have a~96% filtering efficiency vs. the AC Delco (?) at 99%...it's not an argument. However, what is an argument is whether 3% less efficiency makes f all of a difference to your engine. I like the extra flow. I'm running a larger turbo/software to make substantially more power than stock and yes, the modified OE intake I have with a high-flow filter matters. In our Atlas? The only reason is the once/done re-usability and the extra noise you get b/c the soundwaves from the intake aren't as muffled by it like a paper filter.
Best post in this thread.