As some of you with longer memories, may recall, I posted a topic three weeks ago regarding my use of K & N filters in my new 3.2TL-P. The second phase of my experiment involved using D5 exclusively, which I have done for two tanks of gas now. Car now has 2300 miles and hasn't had first oil change yet.

Before K & N filter:
18 mpg
19.8 mpg
(Average: 18.9 mpg)

After K & N filter, "assertive" SS driving:
20.8 mpg
20.3 mpg
(Average: 20.6 mpg, 8% mileage increase)

After K & N filter, "assertive" D5 driving:
21.8 mpg
21.5 mpg
(Average: 21.7 mpg, 13% mileage increase over before K & N, 5% better than with SS)

As someone else in this forum said, you can't beat the computer!

The last phase of my experiment will be on a long-distance trip. I'm planning a trip to Detroit to view the North American Int'l Auto Show tomorrow (3 hour drive from here), and I'll see if I can beat the official highway mileage.

The results so far are much better than I thought! And for you fellow geek types, I'm just too lazy to apply the T-tail test to determine statistical significance....

 

I think there are a couple of factors you neglected in your experiment. First off, I think for the first couple thousand miles the mpg on your car gets gradually better which may skew your results a bit. Also, were you driving on the highway versus city. That would be a factor too. I'm sure the filter helps a bit, but I'm not convinced yet that it's that big a factor.

 

Did someone said that ......Oh yes it was me

Cool thanks for the numbers.

 

You post two excellent points. First, the mileage (as posted in this forum numerous times before by multiple observers) increases a bit, though the reasons for this are fuzzy (I checked, I've got REAL oil in my car!). I'm not sure it explains this increase, though. I'll update periodically--I drive about 2000-2500 miles a month.

Second, my driving is mixed city/highway (70% city, 30% highway), and is similar between all the mileages computed above.

One variable I didn't take into consideration is the K & N says its filters are more efficient as dirt settles into them, as this smooths airflow better. In theory, this means that mileage should improve as well. We'll see whether this blather is true.

 

At 2300 miles as was mentioned I think it is kind of early to run this kind of test.

As far as mileage improving as the filter gets older, K&N says filtering will get better as the filter gets more use as the dirt and contaminants already on the filter will serve to act as another screen for new dirt coming in. There is no real break in for the filter itself unlike the engine.