1SilverGT

I heard on another forum that replacing the stock air box with a k&n filter would work as good as an aftermarket CAI
Im just worried about hot air going into it

What do you guys think? Yay or nay

Goldenpony

Nay. Gotta throw the BS flag on this one. K&N benefits are pretty much a myth, and they don't filter as well.

FiveSlow87

Ttttt

P51C

I noticed zero improvement with the K&N over the factory paper filter and I'm in the 11s on a full-load GT, through the factory filter and box.

TedG

I read a test about air filters and K&N didn't do all that well. Surprisingly, the GM brand (AC Delco) gave the best performance. And it costs a lot less.

P51C

Was that the, hmmm, somewhat bull**** test on SVT forums everybody quotes? How the K&N lost 2 horsepower over the factory filter? There's so many holes in that thing it's lookin' like Grandma's doily. Nonetheless, the dragstrip proved to me there was nothing to be had here in back to back mph testing.

Goldenpony

Maybe not. I heard from one of the top mechanics in a Chevy dealer here in Cincinnati he SAW a 2 HP loss ON A DYNO with a K&N filter. When they put the paper filter back in, the 2 HP came back. Just sayin'

2012StangMan

Ford knew what they were doing when they designed the factory airbox. On a mostly stock motor, it is best over other CAIs.

MrSandman

The stock airbox is already capable of pulling in more air than the engine can deal with. Adding a higher flow filter does nothing.. since the stock filter already exceeds what the engine needs.

The BOSS comes with the same airbox and filter as a regular old GT... and that engine pulls in more air.. That fact should give you an idea of how good the stock airbox really is.

A CAI on a stock GT engine is worthless as a performance mod for that reason. It could technically be capable of pulling in twice the airflow.. but the engine cant do anything with it.

Even with the BOSS.. adding a CAI alone isnt helpful. The bottleneck in this case is the throttle body, and that needs to be upgraded just to utilize the extra flow a CAI can provide.


Keep your stock filter and spend the money on something else. People who buy a CAI are spending hundreds of dollars on an appearance mod.

Xann27

On this note, I run a 14 GT premium, and it has the stock CAI. i rounded 14k miles and did the service at Camelback Ford in Phoenix. they said i need to replace the filter asap, as Arizona air has TONS more dust in it (microscopic) than most other places in the U.S.. When I took the filter out, sure as snot the filter was brown and blotchy. Heres the issue I have. As the GT is mainly highway miles, 60 round trip per day, and i get about 24mpg, I replaced the filter with a WIX from Oriely. The guy there said K&N units on newer mustangs are very unwise. as the factory stuff is better. They didnt sell motorcraft units, so I snagged the WIX unit for $12. hell of a deal. after a few days i noticed the MPG dropped considerably. Im hovering around 20-21mpg. same driving style, cooler ambient temps as well. Whats the deal? should I kick the WIX and go with Motorcraft again? I enjoy having the 5.0 and getting 24mpg... but losing MPG is kinda painful.