Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Stock airbox + K&N question

There will only be a benefit in stop and go traffic or idling at a light. Once you get your car rolling 30mph there is enough fresh air flowing for an airbox to have a negligible advantage over an open cone filter in the engine bay.
However, while you're staged at a drag light and the heat is soaking, you will have to be almost into the 1/8th mile before that good fresh air really has an effect.
The best would be to have a fender mounted filter, as big as you can fit feeding a 3" intake pipe, or a nicely designed airbox with filter being fed by at least a 3" pipe or bigger.
The stock airbox is too restrictive with too many 90 degree turns.
A stock SVT airbox is pretty decent for an average contour but the restrictive opening through the fender is just too small for it.
On my 3L my SVT airbox w/K&N drop in was a dyno-verifiable restriction, to the tune of about 5 HP!