Ok, so my K&N E3270 showed up and I made it out to my 1.7 to take a look at it this weekend.
So... first off worth mentioning is how the factory filter is supposed to fit. snug around the inner ring. So snug that you can hold it upside down without it falling out.
Click to view attachmentThis is how it was designed to seal, not via the top and bottom. Thankfully i recently drove through Redrock country and the remnants of this in my air filter housing make it very apparent. You can see on the top part of the filter housing how little of the filter is actually touching at the top as dirt has made it all the way into the inner most ring
Click to view attachmentComparison of the Factory filter and the E-3270
Click to view attachmentClick to view attachmentClick to view attachmentClick to view attachmentClick to view attachmentClick to view attachmentOverall height of the E-3270 is roughly the same height as the inner ring of the factory filter however the OD is slightly larger so it isnt grabbing the inner ring though it is close enough that there are no gaps in the upper and lower contact surfaces. Also the OD is not as large and there are less pleats in the filter material, so I imagine there is considerably less filter material overall, not necessary a bad thing, just means you may need to service the filter more often, but the K&N is washable so that is somewhat of a non issue.
Upon test fitting it the height is perfect. the housing can be clamped closed with only minimal pressure and once the housing is clamped down there is no movement of the filter at all. I suspect this one should seal well enough to actually filter the incoming air.
However after this filter arrived, knowing how they fit now, I decided to poke back into the K&N catalog and found a newer filter that wasn't previously listed last time I looked...
The E-9145 has an ID listed at 124mm (3mm less than the E-3270) and 82mm height (1mm shorter than the E3270). This may be a perfect fit on the inner ring. Biggest possible downside I see is the OD is only 149mm where as the OD on the E-3270 was 160, so its going to be even thinner (12mm vs 16mm) and most likely have even less filter material. Its also 15 bucks cheaper. (actually as I was able to get this one with amazon prime free shipping it came out like 30 bucks cheaper $55 vs $85 )
Only one way to find out how well it actually works though, and I like spending money to know things i guess, so i ordered one up, should be here this week.