The M1 EP filters have a micron rating of 30 and trap over 99% of particles this size. It's flow rating is 672 GPH. The K&N filters down to 10-12 microns and flows 960 GPH. It took some time to glean this information from multiple sources across the internet.
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Yes, it will fit your LY6 too. These motors were designed to run the short filter but will safely run the longer filter which is what GM uses in the V6s and Gen V motors. Notice, the chart above includes only premium filters but for thirty plus years I've used FRAM and Pennzoil without issue in other autos. For this particular truck in our stable, my desire is to run the premium stuff.
Got me even more curious now, James.
1. Where did the 10-12 micron rating come from? Is that nominal? What's the efficiency? I can't find it anywhere.
2. I see on the Mobil1 website, 99% at 30 microns.
3. I know from prior research that the ACDelco pf44 that turned pf46e was a change from 30 down to a 10 micron rating (in an email I found from Delco) yet even their top dog UltraGuard shows 98% at 25-30 microns on their site.
Here's why: Nominal ratings vs actual efficiency.
I can (and do) buy lots of filters for different industrial applications. A filter rated at 10 microns nominal (which is my bet for the K&N, as nominal ratings are pretty common practice) may only be 50% efficient at that resolution. Given the 98&99% efficiency boasted on the Delco and Mobil websites, their nominal ratings may very well be the same or better than the mysterious K&N # (assuming the 10-12 number is nominal). I'm betting all three have almost identical "premium" synthetic blend media.
Would love to see some actual spec sheets.
Just an example table from one of my suppliers: