Possible 6% mpg gain from adding a cone filter...Ford Focus...

[thomason2wheels]

Originally Posted by suspectnumber961

Strict A-B testing would give erroneous results due to ECU adjustments over time.

IF I continue to see an avg gain of 2 mpg over time...even in cooler weather...I say it's case closed. I'd even settle for 1 mpg.

Will be interesting to see if anyone actually tries this...I'd recommend a Focus....similar year.

I'll go trade the wrx for a fucus tomorrow...... not! Replaced stock panel filter with the k&n replacement on the wrx and while i know the mileage has not improved, what i do know for sure is that i have increased the service interval to prob at least 50k miles. That makes it worth the trouble and expense. Sort of klike why i use synthetic lubes...reduced servicing is a great thing.

[niky]

Originally Posted by suspectnumber961

* reduction in intake restriction?

Has no effect, at all.

As I tried to explain earlier, any change in fuel economy will most likely come down to specific MAF readings and how they are altered by the intake placement or choice of intake material. Venturi effect? Only so far as it alters the amount of air passing by the sensor. Can't make definitive claims unless and until you run a diagnostic and see what the specific difference is in sensor readouts.

Originally Posted by suspectnumber961

But you must BELIEVE!

Simply believing is not enough. Because buying an air filter for fuel economy is not a "one-size-fits-all" solution. Good for you if you see a fuel economy benefit, but most people on here are very skeptical of any result where there is no rigorous A-B-A-B testing. In other words... stock filter, aftermarket, stock, aftermarket, on the same day and hour, the same road, the same direction, in the same car, with all other factors controlled.

[suspectnumber961]

Comparing mpg results from around the same period last summer I get 35.2 mpg for the summer of 2011 vs 37.1 mpg for the summer of 2012....a gain of 5.4%.

Possible explanation for an mpg gain?

http://www.autospeed.com/A_110771/cms/article.html

The cone filter has a bellmouth shape molded into the rubber inside....while the stock airbox has a straight pipe with a sharp edge and the air has to turn 90* from the filter.

How does this relate to intake blocking? Not sure.....

[pete c]

I suspect your gain is the result of adjusting the nut behind the wheel which is without a doubt the best mod ever mentioned on this board.

The fact that you are on this board suggests that it has happened. I question the increased periods between servicing. Are you refering to air filter maintenance? Perhaps that service period is extended, but, it is an extremely easy maintenance, so I doubt there is any sort of cost benefit.

As for the effect on other maintenance, I can't imagine it would help any. It could hurt as low restriction air filters may let more crap past meaning engine wear could increase and your oil could get dirty quicker.