im blown

So I bought and dropped in a K&N air filter (drop in replacement for stock) and instantly noticed a 2mpg difference in the city and about 4mpg difference on the highway (31mpg at 70mph for 1 hour straight @6000ft elevation). I haven't noticed much of a difference in performance by the seat-dyno (how hard you are pressed into your seat at WOT), but the mpg increase will pay for itself soon... I am bored, so I did the math out and figuring the following I found the distance until the filter pays for itself.
Premium fuel on Peterson AFB: $2.35
Highway MPG before K&N: 27. Fuel cost per mile $0.087
Highway MPG after K&N: 31. Fuel cost per mile $0.075
Savings of $0.012 per mile
Cost of filter $50
Miles until fuel savings reaches $50 (filter pays for itself): 4166 miles

I thought this was pretty cool considering the filter gives you better performance as well and is a lifetime filter.
-Joshua

JMJ3rd

Little more than half an oil change and it's paid for! Cool!!!

seesawbob

New guy hear. I've always been somewhat confused by K&N. Here is my issue; more air (less restriction) means more dirt that gets to the motor. It's a well know fact that K&N do not filter as well as a stock filter. So my dilemma is this; save a few bucks on gas now or spend a lot on a filthy motor later.

kphonik

You get 27 MPG?? Are we talking about the same RDX? I don't think I've ever calculated mine at more than 22 mpg, and I use a fuel tracking app on my phone for accuracy!

venom550pm

my wife's gets about 25 on the highway.

lindros2

20-21 here. 27 seems impossible.

cwepruk

LOL at 27 and 31 mpg.

I think at a steady 55-60 mph, you might get 25. At 70, I get 23 (with a K&N).

corduroygt

I got 25 mpg at a constant 65 mph. This is based on the onboard trip computer of course, so it may be a little high.

cwepruk

Maybe he's using Imperial gallons (shot in the dark)?

im blown

No imperial meaurements here. I reset the trip calculator as I set the cruise control on 70mph and averaged 31 mpg for the trip to and from Denver (my home is in Colorado Springs). I don't see how you guys only get 21-22 mpg on the highway, because I get 22mpg in the city in stop and go traffic. Are you guys driving it like it's a racecar or what? It is a fun little ride, but it definitely isn't what I consider "fast" (my other ride is a fully built Lightning= "fast").
-Joshua

calcio22

Just came back from a NC --> NY drive -- all highway, but averaged 25mpg according to the trip computer. no K&N. Avg speed was 70-75

cwepruk

I routinely drive at 75 on the highway, zero WOT and I never get better than 23.5. Each 5 mph is worth about 1mpg.

City is 18 or 19 if I'm good. I get on it once in a while, but I hardly drive hard.

bgillette79

The trip is always 1-2mpg HIGH based on my real fuel up calculations.

Go check this out. It is all my fuel data.

http://www.fuelly.com/driver/bgillette79/rdx



I got nearly 23mpg going 75-80mph steady on my weekend camping trip.

I don't think 27mpg or 31mpg is even possible in the RDX even on totally flat ground at 65mph!

I think 25mpg might be possible around 60-65mph on flat ground. But as soon as you get a little incline that turbo kicks in a little and there goes your MPGs!

ps...I too use the K@N drop in and I DID notice a good difference in performance and MPGs!

MMike1981

w/K&N: expect 24-25 high end highway, 20-22 low end, which means expect about a 22 or so avg highway....with the stock filter, it was quite hard to get the truck over the 20mpg mark...it happened a few times for me, where it shot to 26, 27, even 28 for the TANK...but looking back on it, never happened again, and basically was a fluke

city is where i have seen a major difference. 80% of my driving is city style, lights, stops, 5, 10 min trips. my RDX used to get 13,14,15 (id avg out a full tank around 15 full city) the K&N brings me to a routine 17/18 or higher.

wspy

I have the Cp-E intake that is said to lean out the mixture a bit and if i get 14mpg I'm glad!
I have never seen 20 anything ar even close!

superpowers

buy my hondata, i'm selling it for $750 shipped this week only it'll give u better mileage. haha

and an extra 30ft lbs of torque

JMJ3rd

pm sent on hondata!

MMike1981

thats bad, almost sounds like a problem.

SinCity

Installed K&N several months ago and haven't really noticed anything.

JMJ3RD: Your RDX is looking good. Do you have anymore pics?

JMJ3rd

Thank you very much! Sorry not yet. Haven't had a day off to clean her up. Hopefully soon.

JMJ3rd

I'm guessing not much highway driving there. That's probably what I'd get if I didn't have a 70 mile round trip to work.

JMJ3rd

im blown must be using jet fuel to add to his mixture there on the AFB!

john50

Superpowers - just sent you a PM on the Hondata ECU

CSpaR

WOW 31 mpg! Holy hanna! I get around 18 or so city, and some times, like coming out of Estes Park, CO down the mountain about 25mpg. I think most of the time when I check, it's reading around 21-22mpg. Just bought a K&N from Autoanything.com. We'll see what the increase is when it delivers in a week or so.

Munkslyr

I usually set the cruise at 80 on the highway and usually get 23mpg in my 07 RDX Tech. I dont think i have ever seen 25mpg I think I got 24mpg once. I just put a K&N drop in about a month ago so I need to check to see if it made a difference.

LoDRpR

can you please tell me if the K&N filter you have installed is this one: http://www.knfilters.com/search/prod...x?Prod=33-2382 ?

crazycated

Yes it fits all models 07-09 RDX .

CSpaR

I found this filter at Autoanything.com for $49.35 with free shipping. Good deal I thought. Mine arrives today.

LoDRpR

pff... just threw a question about the price of this filter at some local shops... around 120$ thieves..

CSpaR

Mine just arrived and I installed it in like 5 mins. The old filter is about twice the thickness. I have only 10k miles on it, yet the green underside is covered in dirt! yikes.

I'll report back on any changes in sound, fuel econ, etc..

CSpaR

Okay, I have had this filter in for 2 weeks now. I can see the difference in my gas milage. I saw 24-25mpg hwy yesterday, driving to Denver at about 70-80 mph avg. Sooo, yes there seems to be about a 4mpg difference in Hwy, and 2 or so diff in city mpg. Nice!

I didnt notice any real increase in pick-up or sound, but it maybe there. I'm just not that tuned to those aspects.