OK, here we go. I have tendency to over explain so this will be kind of long.
I need to back in time a few decades. Also we need to talk about diesel engines a little.
I could go farther but lets go to the 7.3 powerstoke diesel. in 1993 Ford had a "turbo diesel" option, that only lasted about 8 months before the 94 model which was still labeled "turbo diesel" but is actually 100% the same as the 1995 "powerstroke" ( little trivia there)
So a diesel engines have no throttle plate to limit air flow into the engine,
(yes more modern diesel do have throttle plate but that is used to enable egr flow, because no throttle plate means no engine vacuum which makes egr hard to accomplish)
anyway gasoline engines require air fuel ratio to be between 10:1 and 18:1 (14.7:1 is considered perfect) if the air/fuel ratio is outside this limits and gasoline engine will not run.
A diesel engine doesn't work that way, it has unlimited airflow and is always getting all the air it can take in. Fuel is what what accelerates a diesel engine. timing and fuel make power but only fuel will make the engine rpms go up.
At idle diesel air/fuel ratio can be 400:1
With that a turbo diesel engine uses 9 times more air than a NA gas engine of the same size. So a 7.3 turbo diesel engine with 100,000 miles has consumed as much air as a 7.5l (460 CID) big block ford engine with 900,000 miles. compared to a NA 3.5 it would be the same as over 1.8 million miles.
Air filtration on a turbo diesel engine is no-bull-shit. #1 cause of diesel engine failure is dirt ingestion.
When the powerstoke came out it had a filter about 8 inches tall and an oval shape roughly 12 inches at its longest point. If you cut the filter and rolled it out it would have been 8 inches by 3+ feet long. This filter had a ton of surface area.
In 1999 when the new model "superduty" came out the air filter was made much smaller, about 8x12 flat panel filter. about 1/3 the surface area of the 1994-1997 version. This set up proved very problematic as air filter life was very very short.
Air filters would get plugged so fast in dirty conditions that the "suction" from the turbo would pull the air filter apart and into the turbo.
In one case a convoy of 5 trucks were going across the desert to repair some power lines. The last truck's air filter got so plugged the engine wouldn't run. The driver removed it. By the time they finished the job and made it back to asphalt roads they had gone 237 miles and that truck had lost compression in 3 cylinders from ingesting dust/dirt. Total mileage on the truck was 7,244 when the dealer I work for replaced the engine. This is on an engine that easily goes 300,000 with about 0 effort and over 500,000 with good maintenance.
Navistar engineering told me, the 7.3 can handle approx 1 cup of dirt over it's lifetime. All at once or over the course of 1,000,000 miles it didn't matter.
Customers looked for a solution and this is when air box modification/replacement became a huge thing. But having seen 100's and 100's the K&N style filters, they do not filter very well at all. I have seen 100's of diesel engines damaged by poor air filtration. I can honestly say that of the 100's of diesel engines I have seen with low compression less then 5% have NOT had a K&N style filter, and if you take out those that had over 200,000 miles I would it would be less than 1%.
Sorry I am rambling
in 2003 the 6.0 powerstoke engine was released. While famous or infamous, it had 0 issues with dirt getting into the engine and the reason that is, is because the factory air filter was a Donaldson PowerCore air filter.
Donaldson makes air filtration for industrial applications, normally for mining equipment I have been told.
In 2005 Ford released a "severe duty" air filter kit that came with a new air box and a powercore air filter for the 7.3, as far as I know I was the first person in Utah and possibly the nation to purchase one. Having witnessed first hand how well the system worked on the 6.0 verses the 7.3 air filter system.
In almost 20 years since I have found 0 dirt past my air filter in my F350.
The powercore filter works like this.
lay 2 straws side by side, now block the opposite end of each straw. (assuming the straws are made of paper) Air flows into the open end of one straw, hits the blockage goes through the paper into the other straw and out the open end of that straw. Dirt gets stopped at the blockage and just slowly fills the straw. The powercore filter has 100's if not 1000's of these straws.
Navistar engineering also told me that the original oval 7.3 airfilter could hold about 8oz of dirt before being restricted, the 1999-03 filter was less than 3oz while the 6.0 powercore was over 16oz. and for 85% of customers was expected to last the warranty of the engine which was 100,000 miles without being replaced. The 7.3 version is around 14oz as it is smaller than the 6.0 version.
Fast forward to last year when I got my Raptor and took it out to the desert for the first time. Super Super fine dust, just like flour or talcum powder. Get home and check air filter and just the faintest trace of dust past the filter and I looked for a powercore filter. I would rather have a COBB air box set up for power. Without spending a bunch of money experimenting I didn't see away to install one with the COBB set up and I refuse to allow dirt into my engine for 5-10 hp.
I am not saying the powercore will cost you horsepower especially on a stock set up. But tuned, going for every last HP possible I find it hard to believe the powercore isn't a little restricted over the dual open element set up COBB uses.
This is the environment I am talking about