is it true or false that a simple K&N air filter can, and will add up to 15hp.
or is that in comparison to taking out a dirty wet original air filter that can with a 1988

 

no a new ford motorcraft will out perform a k/n til about 1k miles 15hp no way maybe 5 hp with the air box removed

 

NAH!!! 3 to 5 max

 

With the airbox removed, ie getting the whole fuel injection performance kit, k&n ships a dyno sheet showing about a 9.9hp gain on a stock 99 mustang 4.6 at 4970rpms, and considerably less gain at other rpms, probably only 3 to 5.

 

Hahaha, if your air filter is clogged with 10 years worth of dirt, I could see it adding 15hp...lol

 

Yea, the only way that could be close to that is if it was their whole induction kit, not just a stock replacement filter.