Is too much air flow no good?

[mustangkcode]

Have 04 Excursion with 6.0 and a K&N oval filter. Was getting decent mpg. Changed back to stock filter and cut out a 3" circle behind grille for more air flow. Went back to K&N for better mpg than stock filter. This time I did not cover up hole drilled for stock filter. You can actually see through grille and thru radiator brace and see filter. I figured that more air flow through the hole drilled would be good with the K&N filter. This is where it gets confusing. I get a couple less mpg leaving hole opened rather when there was no hole. I thought the more air flow the better the efficiency:icon:????????_ford

[outlawdiesel]

the stock filter is good for 400 or 450hp.the k&N is not a good filter.you will sand blast your wheel.afe,airaid,tru-flow,anything but k&n.fresh air is good.

[mustangkcode]

Thank you for reply. Can you explain what you meant by "will sand blast your wheel". and what is afe,airraid, truflow? Are these brand names. My goalis better MPG. I found that hard to do with stock filter. When I went to 4" ehaust from the down pipe back and remove kitty, and installed flow tru muffler with K&N I found to get better MPG. What is it that you do not like about K&N? Thank you for your reply.

[baddkarmaracing]

people around here say that the k&n will let dirt thru because it doesnt seal properly and you will dust your turbo those were other brands that he listed

[outlawdiesel]

well the best thing to do with that K/N is find the trash can and put it in it.before you dust your turbo and so on.

[GnFnRs]

wonder why that is? i have k&n's on everything.except my X. but ihave ran them for years on atvs and stuff with problems

[h2odrx]

Originally Posted by GnFnRs

wonder why that is? i have k&n's on everything.except my X. but ihave ran them for years on atvs and stuff with problems

Did you mean that or was that a Freudian slip?