Airfilters and milage.

"WindsorFox" wrote but CR says this:

Heck, if you think about it, the fuel efficiency should get better since more air equals more fuel equals more power. Well with a REALLY dirty filter there's less air, so the 'puter sends less fuel. Voila'. lol

Scott W. '68 Ranchero 500 '69 Mustang Sportsroof TS #57. (anyone still using these?) :)

Modern engines are Mass Air Flow engines... they measure how much air actually makes it into the engine. A severely restricted filter is going to affect maximum power available but, for many driving circumstances, is going to be pretty much "transparent".

Older speed/density systems would compute the amount of air taken in by the motor using the MAP sensor and engine rpm (along with, more than likely, TPS).

People sometimes expect that one size fits all... they can't do it with pantyhose... how can we expect them to do it with something a little more complex?

Top postingly yours...

Saw this on CNN last night - a few minutes of "Myth Busting" with the Consumer Reports rep. Bottom line, the dirty air filter won't make a noticeable difference in the way the engine runs, except under heavy acceleration. While fuel mileage will not suffer, performance will.

Keep changing out those air filters.

dwight

I don't totally disagree to a point. If the filter is mildly dirty then the difference in mileage is small. However, if the filter is dirty enough to move the sensor data out the operating range of the computer programs operating parameters then it will reduce mileage.

Gee, in that case a restricter plate over the intake should double my mileage.

What?? Where's the message??

If the filter is that dirty, it will set the check engine light. The effect of a reasonably dirty air filter on fuel economy of a modern fuel injected engine is so close to zero as to be zero.

To affect fuel mileage in a measurable way, the filter would have to be practically plugged. Except at wide open throttle the air filter is not even close to the most restrictive element in the intake tract (the throttle plate is). For all practical purposes, there is no difference between a partially plugged air filter and a partially close throttle.

A plugged filter can reduce maximum power, but the effect on fuel economy is no different than a partially closed throttle (again talking about modern fuel injected engines).

Ed

----- Original Message ----- From: "WindsorFox" Newsgroups: rec.autos.makers.ford.mustang Sent: Monday, June 02, 2008 11:10 AM Subject: Re: Airfilters and milage.

A block of wood under the accelerator pedal will have the same affect and is easier to install. A partially plugged air filter is the same as a partially closed throttle.... (assuming we are talking about modern fuel injected engines).

Ed

Ed, we already beat this horse into hamburger.

"WindsorFox" wrote

Now you're gettin' it. lol

Scott W. '68 Ranchero 500 '69 Mustang Sportsroof TS #57. (anyone still using these?) :)

I actually considered that on a 72 455 Toronado I had at one time.