MPG Mods

Except there is no extra mpg. Your anecdotal evidence isn't as rigorous as the study I posted that found no change.

To each his own but I'd never go to less filtration than Toyota provided. How often are you guys cleaning your air filter?

Since I have gone to 60K intervals on my air filters here is my cost.

Factory filter got me to 30K

I bought 3 air filters from the toyota dealer $15 each $45 at the 30K mark. In the mean time I found no evidence that longer intervals on air filters was harmful and actually results in better filtration than new, because it has trapped particles that help decrease the capture size.

VW has 60K intervals.

I just replaced that 2nd filter at 90K, and will replace the next one at 150K and finally need to spend money again at the 210K mark.

I'm getting measurably better filteration for $45 and 210K.

At 90K over 13 years I most likely won't buy another filter. How many miles are you guys planning on keeping these relatively new Tacomas?

I don't see higher than 3000 rpm in 99.9% of my driving, any additional restriction of the OEM filter at 60K has no effect on my power, this thread after all is about MPG not power.

 

According to the report you linked there is no improved mpg. I read that. However, as the filter clogs the pressure drop from clean side to dirty side increases. In the very clogged filters the report states and shows that the filter deforms from the pressure drop. Once that happens contamination can flow past it into your engine. Meaning...at some point it makes sense to have a clean free flowing filter.

By all means, run your truck how you see fit. I'll be cleaning my k&n with every oil change. 126k miles and counting up to hopefully 500k

 

I just changed at 60K with no deformation like they describe, it was still free flowing. That was grossly contaminated, nothing like 60K.

What I wish the testers would have done was at least find out what the pressure drop was on an actual filter that was used for 30K. They just put rags in and increase the pressure drop by 6 to 8 times the clean filter. That restriction may be way more than a 30K filter.

 

Everyone's area is different, depends on how dusty things get...

 

Sure, but I'd think they'd have wanted to know if 6-8X restriction was at least in the neighborhood of a typical driver on the road.

 

One thing that I have been curious about as I have never used a K&N cleanable but have cleaned other types of filters with compressed air is there is certainly a chance to "cross contaminate" the filter where particles blow off the filter end up on the clean side so that when you put the filter back on you now have dust that immediately gets sucked into the motor. Seems hard to avoid? Is that a potential problem, an OEM doesn't see any exposure to the dirty world except that brief time I take it out of the box and place in in the housing.

 

So youre saying my multiple experiments (for lack of a better word) are wrong? Ok dude, whatever you say. If you wanna come hang out with me for about 10,000 miles we can re-run the test with both filters and then you can tell me im full of shit. Until then, keep reading your studies and dont tell me what i did or didnt do.


And if you see fit to run your filters 30k then go right ahead. To each his own...good idea or not.

 

Different regions will have different dust loads. If your regular route includes dirt roads then filter changes will be more frequent. As always, ymmv.

 

That's what I'm saying.

For ever person that says they gained 1 mpg there's another that says 2 mpg and 10 more that say no change. There is no scientific reason for that filter to change anything.

 

Got ya,

Sorry i kinda went off. I was pretty intoxicated after the game last night and feeling pretty cocky. I shouldnt have been internetting.

 

I'm sure I'd enjoy hanging out with you over some beer and whiskey, and some good music. But I will challenge you when you claim 1 mpg gain with a fucking air filter. There just isn't a reason it could do that. I've kept every tank mpg for 13 years, and my mpg is all over the board from tank to tank, do you have that data? My best run was 4 tanks over 36 mpg, with a filter with 45k on it. I should be embarrassed to admit my obsession with MPG, but I'm willing to pick a fight like this to try to convince you that maybe you weren't that careful in your conclusions.

I'm 5 Avery Out Of Mind Stouts in at this point in the night. With a few 4 oz shooters of Maharaja. I can walk home from work.

 

If you don't top of your tank to the exact same point every time, then your mpg is not accurate. If you don't know the amount of ethanol or winter additive, then you won't be accurate. If you aren't sure of the temperature of the fuel, then it can throw off your calculations. The stock computer is not accurate for all of the above reasons, but if you total everything over a consistent basis like 6 months (try to mix cold and warm weather driving) then you might be able to see what's really going on. But that also assumes you drive enough miles and similar miles during those times. A straighter flow of air into the engine can make a difference as well as a better flow of exhaust out of the engine. So there's no good reason to tell somebody they are wrong one way or the other. I've noticed differences in mpg on 40+ vehicles in the last 25 years of driving by doing little things so they can definitely help or hurt. Usually, when somebody makes a change that helps power/mileage a little bit, they also like the change in drivability so they tend to hit the gas pedal more and negate the increase. So any change you make, you need to keep your driving habits the same for a long enough time to see any real difference. Most of these online tests only show a dyno or short time test which is meaningless. But remember, a short time dyno test is also meaningless because the computer doesn't have time to adjust so things might look better or worse in the short time as well.

 

[QUOTE="JL8Jeff, post: 19265727, member: 243662"A straighter flow of air into the engine can make a difference as well as a better flow of exhaust out of the engine. So there's no good reason to tell somebody they are wrong one way or the other. I've noticed differences in mpg on 40+ vehicles in the last 25 years of driving by doing little things so they can definitely help or hurt. Usually, when somebody makes a change that helps power/mileage a little bit, they also like the change in drivability so they tend to hit the gas pedal more and negate the increase. So any change you make, you need to keep your driving habits the same for a long enough time to see any real difference. Most of these online tests only show a dyno or short time test which is meaningless. But remember, a short time dyno test is also meaningless because the computer doesn't have time to adjust so things might look better or worse in the short time as well.[/QUOTE]

You were doing so well and then you lost me at this point.

There is no evidence that a straighter flow of air can make a difference in MPG from either intake or exhaust, and a lot of evidence it has no benefit.

You toss the 3 most accurate methods of measuring MPG off as meaningless dyno tests.

What is your evidence that these are meaningless? The whole idea that closed loop feedback in a modern fuel injected engine needs a lot of time to adjust is simply BS. No adjustment time needed. The whole point of this study was that the FI adjusts immediately to changes in intake restriction and doesn't effect mpg.

Maybe your automatic transmission needs some time to make adjustments but not you FI, emissions would fail if it took time.

Sorry but these are the most accurate way of establishing differences in MPG with changes, and are highly repeatable and precise. The source I referenced use these test standards. EPA fuel economy rating is determined by driving the vehicle over prescribed cycles on a chassis dynamometer. In the United States, city fuel economy is measured using the Urban Dynamometer Driving Schedule, also known as the Federal Test Procedure (FTP). Highway fuel economy is measured using the Highway Fuel Economy Test (HFET). Another relevant test is the US06, an aggressive (high speed, high load) test used to confirm emissions compliance during aggressive driving.

 

If you ever watch your long term fuel trim (LTFT) numbers, you'll see they are not very close to the short term and that will show you why it takes time to get the best overall calculations. A chassis dyno is nowhere close to real life driving (towing a boat uphill against the wind in a rainstorm) so don't look at those numbers. 35 years of real world driving carb and EFI vehicles 2wd, fwd, 4wd, AT, MT, short tires, tall wide tires, etc will show you real world numbers. And that is only in your area of the country which doesn't apply to other areas. I don't have studies, but the best evidence of changes for me would be my 1989 Cavalier Z24 with the 2.8 v6 with 5 speed that got 22 mpg avg through 6 months of driving using 87 octane. I changed to running 93 octane premium and the next 6 months avg was 24 mpg. Both were a mix of winter/summer. Obviously the 93 octane cost more but it ran better and got better gas mileage so I was more than happy to run it. A new air filter is not going to get you 10 mpg but in the long term, it can easily get you .5 mpg better if you drive like normal. A better flowing exhaust will do the same thing. Factory installed components have to meet certain noise, emissions, materials, cost requirements so there is no way they are the best designed setup for the engine.

 

And you don't believe in vaccines either?

So you think that restricting your intake as this study did will eventually show a decrease or increase in mpg with more time?

I frequent several mpg related sites besides this tacoma specific site, and none of them find intake and exhaust a source of increased mpg, you are just assuming this is true with the claim that factory is designed with compromises.

A difference in restriction between a new OEM and a K&N vs a clogged filter is the discussion, your premium was likely E0 vs E10, another topic.

I used to get 34-36mpg on E0 with my Tacoma, now I can't get much better than 30-32 on E10. And I have records of every tank.

The whole idea that something that increases HP will save you gas if you don't use it is false. No it isn't easy to get 0.5 mpg with an air filter or exhaust as you claim.

 

I think your only supposed to do that with the radial air filters that have a an inner and outer filter

 

I give up man. Im not arguing over something i know that i witnessed. Doesnt matter to me if you believe it or not. We will have to agree to disagree and im out.

 

An engine is basically an air pump. The more incremental improvements you can make to that process, the better. Along with aerodynamics and weight reduction you'll save gas. However, we're all in the wrong category of vehicles to take it very seriously. See what people do to hypermilage a compact car...

I don't believe a drop in k&n filter alone is going to change your world. I also dont believe running a dirty filter to the point where the pressure drop from clean side to dirty dirty side could deform the filter is a good idea.

Credentials = 12 years of computational fluid dynamics simulation and bench testing

 

A "free-flow" aftermarket air filter does not provide better MPG. Any given engine is able to convert fuel to power at a certain efficiency, depending on RPM, temp, load, etc... and the fuel ratio is carefully controlled by the computer. This means, if you put in more air with a free-flow filter, the computer will put in more fuel and the result is more power. NOT BETTER MPG.
But here is the most important thing: the few extra HP you get from an aftermarket filter, that's ONLY at or near wide-open throttle. Anyone with any understanding of intake systems, they know that the most restrictive element is the throttle plate, and that is controlled by your right foot. Here's another way of stating it: the aftermarket filter may be capable of delivering more air than the stock filter, but the actual amount of airflow is always controlled by the throttle plate.
So anytime you are at or below about 80% throttle - in other words, the vast majority of the time for most drivers - the air filter has no meaningful effect on power output. Let alone MPG.
The main benefit to an aftermarket filter is that they are usually lifetime units and never need to be replaced. So if you keep the vehicle longer than about 100k miles, you will save some money.

 

I agree with everything you said, it really is as simple as you explained. Nothing an air filter can do to change that. As the filter becomes a little more restricted, the throttle plate opens up a little more to compensate, fuel stays the same.

The above mentioned Long Term Fuel Trim (LTFT) only changes with "significant" changes to the intake. A slightly less restrictive air filter that is before the more restrictive throttle plate isn't "significant". Change the intake Manifold or throttle body and it might decide a change is necessary.