DIY: Secondary Air Filter Removal

Unless you also install low friction muffler bearings...









....and fuel line magnets.

 

I removed mine after relocating from sea level to 6500' above. At these altitudes, everything normally aspirated is gasping for air.

I had done it before at 300' sea level and my mileage did suffer. I reinstalled it. Now I just wanna see what it's like up here at altitude.

 

BTW how much is a new air box, anyone know? I have a 2013 4 cylc. in California.

 

No clue, but any dealer can tell you. If you haven't pulled it off, don't. If it's already out then hope it doesn't get checked at smog time and if it does, deal with it then. There are some people here touting power and mileage changes and several others stating there's no change and after testing I believe the second group. Actually, the moment I pulled mine I realized there's no way it's restrictive and testing confirmed it. Like most mods and most people, if you believe it'll make it faster you will think it is. I used real data, the assometer is easy to fool.

 

sub'd

 

??? subbed for the entertainment factor? There is no gain, that's the takeaway that won't change.

 

Sig material....

 

Ok, after reading this thread I've made up my mind and that filter is coming out tomorrow, i live in hawaii, so between traffic and hills I average only to 350 miles per 20 gallon tank. Meaning that I get roughly 17.5mpg.............. and at $4/gallon on post, and $4.40 off post I'm spending at $80/week... no wonder why I'm always broke lol. Ty for the thread I'll update on my mpg

 

If you actually read the thread you should have concluded it's a worthless mod.

 

Remminton,

I lived on the Big Island for 16 years up country. This will ake you taco sound and run better BUT will not save you any money.
I now live in Baja where we have montians too, my 2013 V-6 get's horrible milage ( 12-14) I added a K&N coldbox for $250 and it runs better and has massive power gain when passing BUT no better on milage.
My 2010 Ford F-250 turbo diesel got 16-18 at 80 plus going up hill pulling my trailer.

Bottom line is Toyota's suck now for MPH

 

For better economy buy a different vehicle or do some worthwhile mods like a header or maybe the Tooter intake spacer; not sure if it gained economy as I stopped following up on it.

 

1st tank update:
In a driving situation where I "should" have gotten lower than my typical mileage, I actually got a smidgen better.
Numbers - I'm usually seeing around 21.2 when I do the math. For this first tank after removal I pulled 21.7 and this included a sightseeing trip with 4 adults driving up to 8700 feet in the Santa Fe national forest so a fair amount of uphill from the 5100' base elevation. However, until I can go thru a tank in the same driving patterns I routinely run, not really a valid comparison.

Driving impression:
The first time I drove her after pulling the screen out the motor felt exactly like it had the last time I tried this (300' above sea level, down south). Many folks in this thread talked about the truck feeling stronger or having improved throttle response but then the dyno graphs come along and debunk the possibility. Well, there IS a change in dynamics and it's hard to put your finger on it but the proprioceptive system picks it up and tells me that the change is only occurring in that first 100rpm (or so) above idle. It just feels like there may be some improved cylinder filling going on right in that very narrow range. It would account for the reports of crisper throttle response off-idle and explain that sensation of increased power i.e., the truck leaping from a stop more briskly.

I must also concur with the dyno plots in that once you mill your way past, say, 1,000 rpm that the show is over and the engine doesn't "feel" like it is performing any differently. Whether part-throttle in normal traffic situations or full steam ahead for passing or the fun of it.

So - is this useful? Well, not really. Unless, you do all of your driving at 900rpm or less but this change in off-idle performance probably accounts for the reports of the engine "feeling stronger".

A note on adaptation:
The engines are electronically managed by control units that adapt to changing variables. Before a fair assessment can be conducted between the "with" and "without" filter screen modes, some driving time must be allowed for the ECU to adapt to the change. I don't know if this has been considered by the folks doing dyno pulls but it should be.

Formulaic interpretation:
It seems illogical to assert that fuel consumption worsens but power potential remains unchanged by way of this mod. With constant mechanicals, power available would shift as the resultant of how much fuel + air goes in. Right? So, if we can see more fuel being consumed than it must be accompanied by an increase in air consumption ( the ECU keeping ratios correct via injector opening). However, assuming that driving 'style' remains constant, then only the power required to move the vehicle would be demanded (even if more was available) typically by way of less throttle, and mileage should remain unchanged. That we have seen numerous reports of decreased mileage is another indicator of results being derived prior to proper ECU adaptation where the fuel system may be running in a slightly rich condition effectively drawing more fuel than needed for the volume of air present.

Fun reading, I know.

I'm on my second batch of gas and have remained well within my 'typical' road patterns. With about 400 miles for the ECU to adapt, I'm certain that it has.

Reminder: my driving elevation ranges from 5100 to 6800 feet above sea level.

 

Never thunk it, I agree.

 

Sounds much easier... Will have to try this

 

Great milage

 

Only in California!

 

Thanks for the info, I just took the charcoal filter out and disconnected the tube that goes from the air filter box to the fender wall. I'm going to fill the truck up and see how much better mpg I actually receive from this mod, but i did recognize the increase in throttle response and power after the quick test drive. I'm getting about 18 mpg at the moment do to a heavy foot, hawaiian traffic and allot of steep hills. I will post new mpg in a week, for any possible disbelievers of this free mod.

 

There is good testing that concludes intake doesn't affect mpg. Your one tank that you are now driving differently to prove this non-mod works means nothing.

 

Folks,

I've read this thread and most of it is by seat of the pants, the dyno info is nice but unless the temp and other atmospheric conditions can be corrected for as stated then they are just nice numbers.

I did notice no one has done any pressure drop/restriction testing through out the air intake system. Doing so would verify if the intake system is or is not restrictive. Ref: http://www.autospeed.com/cms/A_111109/article.html
part way down read section about "Intake systems" Don't worry about the vehicles the article talks about - flow is flow. Doing it the way the article describes will identify where the restrictions are and where work needs to be done to reduce them.

One other thing I would be concerned about is the longevity of the carbon filter. What happens when it starts to breakdown? Where are the carbon pieces going when they begin to fall out of the filter?

Suggest picking up an intake system from the local U-PickIt or other for testing and modding.

Just my three cents.

Jakub

 

I did several acceleration tests and monitored the MAF meter readings, all done immediately before and after removal, no changes I could find. If the airflow rate didn't change then the pressure didn't either, or at least not enough to affect airflow which is what we're after for performance. I then swapped my gutted box with my friend's stocker with 70K miles (without telling him what I was changing) and let him drive it a few days and then swapped back; no change reported. I then swapped it again showing him the removed "smog filter" and he said it was definitely an improvement over the stock box. When I told him it was the same thing I'd done before he realized that what I've said a hundred times is right, the mind is often more powerful than the mod.

There may be parts of the intake that are restrictive, but when you realize that this airbox and filter are bigger than some V-8 vehicles' you might also realize it's unlikely to restrict the mild low horsepower 4 banger we have.

I doubt it'll break down, the carbon is inside a fairly sturdy plastic screen type enclosure and unless they cheaped out on the plastic it should be good forever...or as long as all the other plastic intake parts.

If anyone local wants to swap for a test you're welcome to mine, if you like it you can keep it; I wouldn't have removed mine if I'd known it was pointless.