DIY: Secondary Air Filter Removal

OK, I'll play. Please tell us WHY there's no benefit and the "potential" downsides. I removed mine and it was dark grey. I could not see through it, and even used my compressor to blow dirt OUT of it. I challenge you to run a six mile race with a clogged handkerchief over your nose/mouth...... see the analogy?

 

Nope not the correct analogy, it's not clogged at all, it's free flowing. Your engine breaths just fine while your throttle plate is the primary restriction.

If dirt made it to this filter your primary air filter sucks, see the fallacy?

Your high pressure air nozzle flows about half the cfm through a tiny orifice as this filter sees across a relatively huge surface are. It sees slow moving filtered air. Not a restriction. But shoot a high pressure stream of air at it and you can expect to blow some carbon from it. Stupid analogy.

The filter contains carbon which is dark, hence it looks dark.

Potential downsides, none, other than pollution, but it is still pointless to remove for power or mpg.

But you didn't bother reading all the posts on this thread that explained this over and over.

 

You presume a lot. Like how on July 02 of 2011 (post #415 in this thread), you rightfully noted that there would be no fuel/MPG reduction due to the clogged filter. That study (http://www.fueleconomy.gov/feg/pdfs/Air_Filter_Effects_02_26_2009.pdf) does note that "The increased restriction of a clogged filter affects ultimate power but not fuel economy of modern SI engines."

So the testers advised that power was affected. They also stated that "It is possible that there may be some isolated operating conditions under which the fuel economy may be more susceptible to a clogged air filter."

Seems that the explanations were not that explained...... over and over.

 

But the charcoal filter isn't a restriction like that created in the test. Glad you looked back after the fact to try to make a point but you didn't.

Comment on how dirt got past your primary filter and how blowing compressed air on the charcoal filter means something.

 

Again here is what Gadget@URD found at the dyno after removing the charcoal filter. No increase in HP. It's not a restriction.

 

You unwittingly validated my anecdotal experience with my 4.0L Tacoma by requesting information regarding the circumstances of how it got encumbered. Doesn’t matter HOW, what matters is the fact that the secondary charcoal/carbon membrane/filter subsequently contained particulates. Doesn’t matter whether the filter media is charcoal/carbon, synthetic, paper, fiber, or foam---particulates trapped form a restriction.

If a vehicle air filter gets clogged, it will decrease airflow to the engine. The engine combustion process needs this to make power most efficiently. Theoretically (I am not a airflow scientist, but did study laminar flow in college), an air filter possibly might get so dirty that the engine wouldn't run. But what's more likely is that a dirty air filter will deprive the engine of just enough air to hamper performance. Hamper it by how much? Depends on many things. Most naturally aspirated enginees require 10-15,000 gallons of air for every gallon of fuel. So any “restriction” on the airflow can affect performance/efficiency.

The research study that is referenced here by Oak Ridge National Labs reveals that modern, FI vehicles with restricted air filters can reduce power, but won't affect fuel economy in a distinctly measureable way.

This newer air flow/filter study conducted in November of 2014 used a variety of numerical tools in their study, including a finite element flow solver and Brownian dynamics simulation. They do cite the Oak Ridge National Labs study in their experiment.

http://www.ijesit.com/Volume 3/Issue 6/IJESIT201406_46.pdf

Conclusions:

-The increased restriction of a clogged filter affects ultimate power but not fuel economy.
-Pollution of the air filter has a significant effect on fuel consumption and engine’s power.

Toyota does not provide any test/documentation on this secondary filter. Saying that this secondary filter on the 2nd Gen Taco is not a filter is disingenuous. That’s like saying that a catalytic converter is not a filter (it basically filters the exhaust fumes and turns it into a less harmful chemical).

 

Deleted the rest since it is all nullified by gadgets dyno test showing no effect.

Your link is about diesel engines.

I called it a filter, what are you going on about disingenuous.

I said no restriction.

 

Believe what you want to believe. The new study clearly shows that increased restriction of a clogged filter affects ultimate power but not fuel economy. Discounting it is equivalent to saying that vehicle body colors affects the study outcomes. Did the gadget dyno test involve a clogged secondary charcoal/carbon filter? The answer is unknown. The "nullification" is pointless with the preponderance of evidence.

 

If it was dark and you couldn't see through it I suspect your air filter isn't doing it's job; does it have an aftermarket filter? At 33k miles mine was clean and perfectly see-through. Downsides are increased emissions, increased contamination & degradation of the air filter, and possibly failing smog for a removed part. If caught it'll cost you a replacement part and a possible fine and/or impoundment of the vehicle. If you have an emissions system failure under warrantee they might be able to deny coverage because of the removal of a component. Altho rare, I have seen air filters that broken, the charcoal trap would have retained the pieces so loss of a back-up screen can be added to the downsides.

 

A clogged charcoal trap will indeed reduce power potential. The only way the trap would become clogged is if the filter wasn't doing it's job therefore the trap helped save the engine before becoming clogged. I would suspect that using an oiled air filter could cause the trap to clog between the oil making it sticky and all the dirt they let through sticking to the oiled trap, but again it helped save the engine before becoming a hinderance. In this case it indeed became a secondary air filter instead of the vapor trap it's supposed to be.

 

You keep referring to the charcoal filter like it has some chance of becoming clogged. The one Gadget removed showed it caused no restriction that reduced hp.

Under what scenario would you allow your carbon filter to become clogged?

I'll keep discounting your analogies that don't make sense sig.

I never said a restriction won't reduce hp, just that the carbon filter isn't creating a measurably significant restriction.

Let yours get clogged and all bets are off.

 

It does have a chance to become clogged. Just because Gadget's was not does not mean the other Tacomas on Earth will not. Mine did. Driving in dusty desert locales evidently affected it.

I would not purposely allow it to become clogged. The point is that it CAN.

I respect your opinions, but studies/experiments that were conducted prove that filtration media CAN become clogged. When they do, power is affected.

And here again you're admitting that a clogged filter would pose reduced power issues. This is the crux of our disagreement. You maintain that the SECONDARY filter (not affected by particulate masking) does NOT affect HP. I agree with you, but IF the secondary filter was NEVER installed---there would be a zero chance of it reducing HP in the first place. Seeing as it is there, and Toyota says NOTHING about checking it, and advises that it's a "lifetime" issue/part (just like the A/T tranny fluid in our 2nd Gens being good for 100k miles? Why no A/T tranny dipstick? LOL).

Which is precisely why I removed it. I think we both see it differently. I view it as a "Nanny state" issue that could affect my engine. You view it as a EPA issue that has no bearing on fuel economy. We both understand that clogged filtration will affect the Taco engine. I have just taken the stance that it's my truck and I'll maintain it as I see fit.

 

You should invest in better primary filters then SigSense.

If what you found is true your charcoal filter was trapping dirt that is now getting into your engine. Not what you really want is it?

 

Agree 100%, maybe a snorkel is in order, LOL!

 

Hey guys - brand new here...any risk for engine damage if I remove the secondary filter w/ a reg OEM as the primary filter?

 

No risk, or reward.

 

I second worthywads. I removed mine before reading further into this thread and did before/after testing and there was no gain. Leave it in. Now that I think about it, isn't removing smog devices and recommending it against forum rules? Wonder why this thread has existed for so long yet someone talks about pulling a cat. converter and it gets squashed. Maybe if this weren't here with the first several people touting the gains we wouldn't have so many people removing their charcoal traps, I know I wouldn't have.

 

Worthless mod for the 4.0,wished I never did it.

About the secondary filter being clogged, the pcm would just keep recalibrateing for airflow until the airflow was out of its parameters.
It's not a carburated engine, eventually their would not be enough air to mix with fuel and it would be rich beyond emissions standards..but by this time the pcm would of flagged it.
So the secondary filter could plug up.
If you stick with OE filters, I don't see a reason why the secondary filter would ever plug.

 

Hey I have a 2012 Tacoma with the 2.7L ... did you drill out the rivets just enough to remove the charcoal filter , and allow it to easily be re-installed at a later date , with say, small sheet metal screws and hard rubber washers to re-install it to pass smog ?

 

There are many ways to remove it and there's no benefit so just leave it be.