Thor Forums

[Travelin' Texans]

I've ran the K&N in several vehicles with no "Oh WOW!" noticeable increase in horsepower or fuel mileage, did notice a slight noise increase at heavy throttle & never an issue fouling sensors.
Basic physics is if you put more air in you need more air out.
I had an '05 GMC Duramax/Allison that I used the K&N while also replaced the stock exhaust with 4" front to back, this combination did see noticeable increase in power & 2-3 mpg empty & towing.
Not sure that the increase in mpg ever recouped the cost of both the upgrades in the 176k miles I drove the truck, but it ran good, towed a 16.5k lb 5th wheel with ease & sounded great.
Would I replace again with hopes of increased power & mpg........NOPE!
Would I replace for extended filter changes due to the PITA factor.........MAYBE!
If you want to add one I can't see any reason why not, it's your $$$, but don't expect gigantic increases in performance, it does not will not be the miracle cure for the low mpg on a Ford V10.