K&N Airfilters

[tim-in-ca]

Has anyone swapped out the stock air filters for the K&N air filters? If so what has your experience been? I'm more interested in the mileage performance gains than the HP improvement. I'm not heavy footed but in my mixed city / hwy commute, I am getting about 15 MPG. I hear that you can get nearly a 1 MPG improvement. I know that it doesn't sound like a lot but with premium at around $3.60 in So Calif (and going up), it would take around 5900 miles to get the return back of the cost of the filter pair which I found to average around $89. The math is :

Fuel Cost per Gal : $3.60
Current MPG : 15
Cost per Mile : $0.240
Improved MPG : 16
Cost per Mile : $0.225
Delta :$0.015
Miles to ROI : 5933

Thanks for any feedback.

 

[Gregorio]

The 1 MPG improvement sounds like a stretch. I've never seen any improvement in my other vehicles compared to a new OEM. I only like the KN because I can wash them instead of replacing the OEM more often. Some cars do not like them because they can mist small amounts of oil in the intrake tract and possibly foul MAF sensors.

Slow down 5 MPH on the highway and you will gain that much for no investment at all.

 

[Big_Mark]

I recently installed a K&N air filter on my 2006 LR3. I didn't really notice any performance or mileage gains/losses. I too prefer the K&N filters but the "resident experts" seem to think the oil from the K&N filters can/will ruin the MAF sensor.

You'd probably be better off just leaving the stock one in until it's time to change it out.
Also if you search E-bay you can get a better deal than $90. I got mine there for around $40. shipped!

 

[buckeyeLR4]

I think K&N addressed the MAF sensor issue a while ago.
http://www.knfilters.com/news/news.aspx?id=422

 

[Big_Mark]

Thanks for the link!

Confirms what I suspected FUD is as strong on LR forums as it is on Jeeper forums... LOL

 

[Gregorio]

I don't take manufacturer propaganda very seriously. Hard to not draw a line from a misbehaving MAF to a recently installed K&N.

Back to my point about speed having a bigger impact on mileage. Just drove from SF Bay Area down to Indio. First tank was 270 miles on highways 101, 152 and 5 (70mph speed limit for 200 miles) with an average speed of 77mph with peaks of 84 (speed alarm setting). No wind and light traffic so there was very little heavy throttle needed for passing maneuvers. Mileage was 16.8 on the computer and 16.91 hand caclulated. Next tank was 197 miles on highways 5 (over the Grapevine pass), 210 and 10 with an average speed of 73 mph with peaks of 84. Traffic was much heavier and several near full throttle blasts were employed to overtake slower vehicles. Mileage on the computer quickly reached 19+ once in Pasadena and stayed near there until the speed limit on highway 10 went to 70mph and I set the cruise on 80. Average MPG on this leg was 18.4 on the computer and 18.44 hand calculated.

These results mimic my previous trip down here and I expect the same results on the way back tomorrow. 4MPH average reduction in speed netted almost 1.5 MPG gain. Not bad for a minor time investment.

 

[Count Laszlo]

That's really impressive! I'm getting great results as well. Hard to believe for such a beast.

 

[antichrist]

Yes, MPG drops significantly as speed increases because wind resistance increases at a faster rate than speed.

When thinking about K&N's keep in mind that that supposed power and/or mpg increase (assuming it exists I've never seen an independent study showing either though), is because they flow more air and that allows more dirt through the filter. Independent tests have shown K&N's pass more dirt in to your engine.
Additionally, the K&N warranty is voided if you use their filters off-road, even in applications they make them for, like dirt bikes.

Stick with OEM or a quality filter like Wix.

 

[tim-in-ca]

I'm probaly going to opt out of "upgrading" to K&N .. who knows if I experience an engine issue in the future the dealer my try to "wiggle" out of the warranty if they find "non-factory" parts in the engine.

As for MPG and driving style. I'm actually a pretty conservative driver and drive typically about 7 MPH over the posted speedlimt to stay "under the radar". I don't do jackrabbit starts as well. I have yet to take the truck on a long sustaned trip (i.e. to Vegas), but in my daily driving I only get 15MPG at best using the hand calculated method. The trip computer ALWAYS over estimates my mileage by at least 1.5MPG or more! I put premium in as well. Oh well, guess I gotta live with it and just enjoy the truck!

 

[antichrist]

I'm probaly going to opt out of "upgrading" to K&N .. who knows if I experience an engine issue in the future the dealer my try to "wiggle" out of the warranty if they find "non-factory" parts in the engine.

It's against the law for a warranty to be voided for the use of non-factory parts as long as they meet specs.
In the case of K&N air filters that have been proven to let through more dirt, and that logic would tell you they do, then yeah, you might get push back on any engine damage claims from the dealer. And if you ever go off-road you've voided the K&N warranty. So yeah, staying away is a good choice.