Honda Insight Forum banner

1 - 20 of 39 Posts

·
Registered
Joined
·
73 Posts
Discussion Starter #1
Alright, I know there's ALWAYS a ton of debate/discussion around performance air filters, but I've got some results that I'd never have expected, so I thought you all might enjoy hearing about it.

I pulled out the OEM air filter and decided I didn't like it at all; it looked cheap, felt cheap, it's like an air intake tampon. I was displeased. I decided to buy a K&N filter from Amazon because it was about $10 cheaper than through my local parts store, even with next day air, so I jumped on it. I swapped out the filters, threw the OEM filter next to the spare tire for the inevitable 24 hour cleaning the K&N will need, and did some driving.

Here's the deal: I'm using stats from the last tank of gas; I've only burned part of the tank since the K&N filter, drove the same routes using the same driving style, the CC is not on. Here's what my early results are showing:

Tank average with OEM filter: 47 mpg.
Real-time fuel economy cruising (rough average): ~51 mpg

Current tank average with K&N filter: 51 mpg.
Real-time fuel economy cruising (rough average): ~65 mpg

It's still early in the tank, but I haven't gotten these numbers consistently out of this car during in town drives, so this is a major improvement. Once I'm further into the tank, I'll update this number.
 

·
Premium Member
Joined
·
1,632 Posts
Just for grins.....after this tank is done, put the OEM back in just to make sure your MPG goes down again.....The reason I suggest this.....there may be other factors involved in your recent higher MPG

Warmer weather is always a positive towards higher MPG....
Driver getting more experince with achieving higher numbers may also be a factor.

I'm not saying the K&N is no good but like with any test or troubleshooting, you should be able to produce predictable results and if you don't try it, you will never know if other factors were involved.

JoeCVT = Just your average CVT owner
 

·
Registered
Joined
·
73 Posts
Discussion Starter #3
.....after this tank is done, put the OEM back in just to make sure your MPG goes down again.....
But of course! What kind of an experiment would this be if I didn't at least try to rule out possible variables?
 

·
Premium Member
Joined
·
9,983 Posts
Interesting.... I am tempted to try cleaning mines or try a standard filter again.

I found with my super charged tacoma I was cleaning the red filter that turned black after 2 thousand miles of use always gave a bit more performance for a few weeks til it blacked up again. I could hit 15 vs 13 psi of boost too with a fresh cleaning.
 

·
Registered
Joined
·
64 Posts
Why the heck do these K&N filter discussions pop up on every automotive forum known to man! Surely with a car as complex as the Insight, the air filter makes little difference! Heck, try running the car for one tank without an air filter at all! You should see better improvement versus the K&N, right?
 

·
Registered
Joined
·
73 Posts
Discussion Starter #7
Why the heck do these K&N filter discussions pop up on every automotive forum known to man!
Automotive Forum. That's a major contributor to the problem. Automotive forums have a tendency to be infiltrated by tech-savvy motorheads who love nothing more than big block V8's stuffed under the hood of an El Camino or Catalina just to hear it roar and visit every gas station in town.

Those guys tend to be obsessed with performance parts, like the K&N filter. The reason the air filters come up so often is because they make them for virtually everything. Not many people will be looking for new headers for their Insight, but everyone replaces the air filter at some point...and that's the appeal: it's easily accessible and it's a part associated with better performance.
 

·
Registered
Joined
·
303 Posts
Classic placebo affect me thinks :)

Modern cars operate on a "closed loop" and as a result the air filter has zero affect on gas mileage, it can only affect top end HP when the air filter becomes the "throttle" restricting total air flow.
 

·
Registered
Joined
·
64 Posts
I think we should break into these people's cars, replace their K&N filters with stock ones without telling them, and then come back on the forum. I bet you they will still be singing the praises of their increased gas mileage with the K&N filters... with a stock paper filter.
 

·
Registered
Joined
·
73 Posts
Discussion Starter #11
Classic placebo affect me thinks :)

Modern cars operate on a "closed loop" and as a result the air filter has zero affect on gas mileage, it can only affect top end HP when the air filter becomes the "throttle" restricting total air flow.
Two problems here:

1. I'm not doctoring my math or changing my driving habits. It's just the number I'm getting off the dash.

2. I don't think computers are susceptible to a placebo effect, but I'll start telling my Honda that it has a paper air filter in it, just in case.
 

·
Registered
Joined
·
73 Posts
Discussion Starter #12
I bet you they will still be singing the praises of their increased gas mileage with the K&N filters... with a stock paper filter.
That's not exactly what I started here, I was just remarking on an anomaly in my fuel economy immediately after having changed the air filter. I don't see any reason to knock the guys who claim to get better fuel economy out of it, though, because it's plausible under the right conditions.

Alright, I know there's ALWAYS a ton of debate/discussion around performance air filters, but I've got some results that I'd never have expected, so I thought you all might enjoy hearing about it...


...It's still early in the tank, but I haven't gotten these numbers consistently out of this car during in town drives, so this is a major improvement. Once I'm further into the tank, I'll update this number.
 

·
Registered
Joined
·
64 Posts
1. You mean you're not knowingly changing your driving habits.

2. The placebo effect affects you, not the machine! :bonk: :D
 

·
Registered
Joined
·
64 Posts
That's not exactly what I started here, I was just remarking on an anomaly in my fuel economy immediately after having changed the air filter. I don't see any reason to knock the guys who claim to get better fuel economy out of it, though, because it's plausible under the right conditions.
Fair enough! :D
 

·
Premium Member
Joined
·
9,983 Posts
My use of kn has never resulted in more mpg, just more power/noise.

Likewise I find more mpg with econ on vs off. Some find just the reverse.

On one forum I read where use of a kn filter was wasnt oiled properly can result in the car running lean as the oil vapor fouls the sensor.
 

·
Registered
Joined
·
466 Posts
According the EPA website they ran a test on air filters and concluded that even a severely clogged air filter had no effect whatsoever on MPG. Pretty conclusive. Here's the link to the study:

http://www.fueleconomy.gov/feg/pdfs/Air_Filter_Effects_02_26_2009.pdf

Results show that clogging the air filter has no significant effect on the fuel economy of the newer vehicles (all fuel injected with closed-loop control and one equipped with MDS). The engine control systems were able to maintain the desired AFR regardless of intake restrictions, and therefore fuel consumption was not increased. The carbureted engine did show a decrease in fuel economy with increasing restriction. However, the level of restriction required to cause a substantial (10–15%) decrease in fuel economy (such as that cited in the literature 3,4) was so severe that the vehicle was almost undrivable. Acceleration performance on all vehicles was improved with a clean air filter.
 

·
Registered
Joined
·
73 Posts
Discussion Starter #17
Alright, final number on that tank was 51 mpg and a little bit of change.

I've been driving through the mountains (and a little aimless driving around Richmond looking for a restaurant that doesn't exist anymore on my way back home) and on this tank I'm averaging a little over 48 mpg.

If this car doesn't end up breaking 50 consistently, I'm going to be sorely disappointed. It's got every bit of the potential to take Toyota's cake and eat it, too. Have you noticed the differences between user reported MPG on fueleconomy.gov? The I2 has been giving the Prius a run for its money.
 

·
Registered
Joined
·
350 Posts
Ok Mr. Popennell, put the OE filter back in and run out a tank. Try as hard to get good mileage as you did with the K&N, try to really use the same driving style. I'm really interested in the results.
Thanks!
 

·
Registered
Joined
·
73 Posts
Discussion Starter #19
Ok Mr. Popennell, put the OE filter back in and run out a tank. Try as hard to get good mileage as you did with the K&N, try to really use the same driving style. I'm really interested in the results.
Thanks!
I'm actually with ackattacker here, I don't suspect there'll be a statistically significant difference in fuel economy between the two (though I can admit to noticing a very small difference in power when the pedal is on the floor). I think the gradual increase I'm seeing in fuel economy can be attributed entirely to the wear in period. I'm around 3500 miles now (man, I'm just racking up the milesand I've seen an improvement on each fill up (excepting my regular trips into the hills).

It'll be difficult to get accurate fuel economy estimates out of the two because I took a road trip to Harrisonburg, VA on the last trip, which meant a significant amount of mountainous driving.
 

·
Registered
Joined
·
9 Posts
K&N is nice but not for the mpg.

It's true about the filter not making a difference in mpg. Modern cars operate with a mass air flow sensor which measures how much air it's able to get in the intake so that it can compensate with more or less fuel to get the proper air to fuel ratio. It really only mattered on older carborated cars which had no idea if the filter was clogged and dumped the same amount of fuel as if it wasn't. I'm not saying it's not economical to buy K&N, I swear by it, all our cars run them. But I buy them because they're washable, so by the second time you wash it, it has paid for itself and from then on it just savings. The other reason is they're made in America, I'm all about supporting 'made and sold by american'.
 
1 - 20 of 39 Posts
Top