Hi Guy's. With today's fuel prices it's great to get good news. I installed a K&N filter in the stock air system of my F350 V10 and have seen a major improvment in fuel mileage. The paper filter I took out was not dirty at all, but my fuel economy from my last tank of fuel prior to the filter replacement and to the latest tank of fuel after filter replacement has gone from 11.1 MPG to 13.2 MPG as measured on the overhead computer, and my miles covered has increased accordingly. The driving done over the before and after tanks of fuel was almost an identical mix of about 50% highway and 50% city driving. With the old filter my overhead computer also reported fuel economy around 10.9 to 11.1, not towing, it had never been higher than 11.1, so the improvement appears real. I will be verifying these numbers with a hand calculation later today. This is my second vehile I have installed a K&N filter in and I am IMHO very happy with the K&N filters.

 

How often do you need to clean and lubricate those?

 

So you are the one. I have had a K&N filter in for a year along with headers, free flowing exhaust, and a tuner, and I never got more that 1 mpg ever. And it would bounce back and forth from no change to 1 maybe 1.5 increase. I dont have a fancy overhead computer to calcutale it, but I do it longhand with a old fashion pencil and paper.

 

I just hand calculated my mileage from my last fillup since installing the K&N filter. My fuel mileage went from 13.6 to 16.2 on my last tank. No change in driving style or roads covered. The only difference in the truck is the filter. My old paper filter didn't seem that dirty but maybe it was. Regardless I am more than pleased with 16+ MPG (US Gallons) with my truck. In Canadian gallons that is almost 19.4 MPG and I know manny other much smaller trucks that don't get as much fuel mieage as I'm getting. Boxcar1974 you know that an increase of 1.5 mpg on maybe 11mpg still is a pretty descent increase of almost a 15%percent improvement. That's nothing to sneeze at. Everybodies results will vary, but you still saw a good increase.

 

I had one in my old 5.8 250 I did not notice much of A difference in mileage with the filter in this truck. I read some place that they aren't as good of filtration as stock paper has anyone else read or heard that. If other people have had fuel mileage sucess with I am interested. Also are they good for factory warranty as fussy as they are today?




2005 SD 250 V10 XLT reg cab

 

the pores on a gauze type filter are larger than on a paper filter. I've never seen any improvement in mpg or hp with any gauze-oiled filter. Unless a dealership can prove that the airfilter caused any damage they can not legally deny a claim. But legally doesn't mean you won't get a run around from the service dept, cause you might. Wow, 19.5 mpg, that's fairly incredible. That's like 50%, I would think the automakers would be installing those to get their CAFE up. The gauze-oiled types work better after they get a little dirty, Ken

 

The 19.5 mpg is to the Canadian gallon, to the US gallon it is just over 16mpg, which is greater than I've seen mentioned on this forum before. Correct me if I'm wrong but most people on this board are getting about 13-13.5 mpg maximum with these trucks. Along with the hand calculated increase in mpg. I have also seen a corresponding increase in the vehicles cruising range on a full tank of fuel. As I said my paper filter did not look all that dirty, but it may have been. Regardless it worked for me on my last tank full of fuel, it will be interesting to see what my mileage does longterm. Cheers

 

My only thought on this is: Where on K&N site, box, adds, etc, does it even mention better or at least equivalent to stock filtering? True, they do claim more air flow, and it does as claimed, but the filtering leaves me skeptical, at the least. JMHO

 

Totally stock V10, Supercab, 4x4, shortbed, I got 16.5MPG (US miles/gallon) once, usually more like 15-15.5 ... ALL HIGHWAY.

Best thing to do with a K&N is not clean it - the more stuff gets stuck the more it filters.

I'm beginning to wonder if it's already coated your MAF with oil and it's beginning to run lean, to get that much of a MPG difference

PS: I use a K&N in my '97 Cougar 4.6L, but that's because the stock air box is so small, any little bit helps.

 

For what it's worth if something as cheap and simple as an air filter can boost HP and MPG the way they say why do the auto mfgs spend millions looking for better performance & mpg instead of just installing these filters ? Just my opinion.

 

I've used both Amsoil and K&N and for some reason I never saw a difference with either but the Amsoil unit looked like it just had a better build quality. To each his own. I've just never seen a mpg difference.

 

I have never seen any increase in mileage either with the K&N, there are a lot of arguments both ways, a lot of tests you can research..