Truck Trend claims 10% more MPG with K&N in 2009 Ford F-150 after bogus road test

[Tweety]

Originally Posted by Christ

That would only work out if the OEM filter wasn't capable of flowing the amount of air necessary at a given throttle angle.

The engine, in our case, hardly ever requires more air than the OE filter can handle flowing, therefore there is no restriction. You can test this with a simple vacuum gauge on the intake pipe after the filter.

Since the K&N isn't flowing any more air than the OE filter was, due to the requirement for air not changing, there is no more fuel being injected, and thus, no change in economy or power.

Engines work on demand, not supply. If the engine isn't asking for more flow by increasing manifold vacuum, it's not getting any more. Period. Full Stop.

Let me start by saying it another way... I'm reasonably sure that we actually agree on the big picture here... But we draw a bit different conclusions... (And we both argue a point... )

I fully agree that as far as the car goes, changing to a K&N filter will only yield a benefit if the OEM filter is restrictive... (How you view it)

As far as the car and user goes, since 99% of the time the nut behind the wheel will use all available power and the K&N can potentially unleash a tad more of that (and most likely does, however marginal)... The consumption goes up...(my version)

The joint version... Claiming that it increases mileage is ludicrous however you spin it... unless the factory design is flawed... And with the average nut behind the wheel mileage will decrese as a total... Not really because you have a K&N filter... But because of the fact that you now have a K&N filter...

[smokeyj]

Ok now, how about a diesel? This has no inlet restriction. If you are going to see a benefit to any of this stuff, I would expect it would show in a diesel before a gas motor.

[Christ]

Originally Posted by smokeyj

Ok now, how about a diesel? This has no inlet restriction. If you are going to see a benefit to any of this stuff, I would expect it would show in a diesel before a gas motor.

Over-oil your K&N on a diesel and you'll have a lot more problems than 10% more HP. They're not really recommended for use with diesels because the average end user doesn't realize that 1 oz of oil really is enough to coat the stupid thing.

Diesel's also aren't throttled by air, so even though there is intake restriction in a Diesel engine, it just limits max HP. As long as there is air in the cylinder for the fuel you're putting in, there is no problem, and once again, an air filter will not increase your economy, unless of course, you normally drive with a straight right leg.