DIY: Secondary Air Filter Removal

Why would you want to do it?

It has zero effect on engine performance, and no it doesn't effect dust since your air filter does that.

You will have to break the plastic rivets that hold it in place and then find a way to reattach when emission time comes.

It really is a pointless mod.

 

+1

My truck will probably need smog next year... debating whether to chance it or just buy a new airbox lid.
I really wish I had never popped that thing out.

 

If you really want it gone I'll trade you for my cover, already cleanly deleted the charcoal filter.
My smog guy is a buddy and won't check it, but if I could go back I'd have left it alone. There is no benefit to removing it and it'll never get dirty and need replacement. There's a minute possibility that leaving it there will help the air filter by blocking the gas fumes from getting to it; probably doesn't matter, but thought I'd throw a positive other than emissions reduction into the mix.

 

I just recently removed the secondary filter, replaced plugs, and ran some lucas in the fuel. I still however see a lag in power when trying to accelerate.

 

Have any of you added the K&N 63 cold air system to replace the factory, what about improved MPG.
My 2013 V^ auto is getting 275 per tank- uggg The truck seems to be running great but milage is horrible

 

Intakes don't improve mpg.

 

I am new Tacoma member

I have been getting around 20MPG on 2011 prerunner which is all stock. I went ahead and purchased aFe Pro Dry S air filter. I have been on the fence about removing the second filter. I am in Texas so shouldn't be an issue with emissions test.

 

Can't offer any real thughts on this, my 2013 is TRD is stock and runs great but gets around 14-16? I just bought the K&N and will install this week.
Hoping for a power booast and better mileage

 

people have reported hp losses as recorded by a Dyno from K&N intakes iirc.

ymmv, just throwin that out there.
they also have terrible filtering properties, and ya gotta make sure to keep the oil on the filter to a minimum and clean ur maf sensor regularly.

 

So, I know this thread is about taking of the secondary, but what about replacing it? Mine got a little wet after I went through some deep muddy water, I thought wasn't as deep as it was, and yes I did get out and check the depth but couldn't get to the middle of water.

 

It'll dry out quickly with the air being pulled through it.

I'd be more concerned about water getting into the MAF and other sensors downstream of the filter... or did it get just enough water to dampen it and not flood out?

 

I am not 100% sure how far it got, I think some did get past the filters but not much, is there a thread on how to clean the sensors?

Thanks!

 

So while you are busy cutting out part of the filtration in the system, you are concerned with debris entering your engine to the point of putting foil over the intake while it's idle?

I understand it is another restriction in the system, but a charcoal filter is a pretty low differential element compared to the paper filter. In my opinion (however little it's worth) it's the same as a k&n filter, your sacrificing the life of the engine for very little gain. The finer dust is just as damaging as the larger.

That being said, a small gain can be quite noticeable in a smaller engine. And with what some of us put our trucks through, it's probably the least of our concerns

 

The foil is simply a precaution and is a good idea any time the intake is removed from the throttle body for any length of time.

The charcoal "filter" is not actually a filter at all, so removing it does not reduce the effectiveness of the intake filtration system.
The charcoal mesh captures unburned hydrocarbons that rise out of the intake after engine shutdown. It self-purges when the engine is running.

And yes, I agree that removing the filter does nothing but perhaps increase noise a bit.

 

I think the title of this thread should be edited.

DIY: Secondary Air Filter Removal; how to waste your time gaining nothing and breaking the law.

I've verified that removing it makes no change using a scanner and watching the MAF numbers at full throttle acceleration. Three runs with and without to 85MPH, same amount of air flow so same amount of power. As for fuel economy; technically it'll be better with the charcoal trap, but to an unmeasurable amount.

 

Here are my last three tanks of gas:

1st tank: normal driving, not aggressive but not overly conservative, "secondary filter" still in place....17.5 mpg

2nd tank: conservative driving under 2k rpms, "secondary filter" still in place...18.5 mpg

3rd tank: conservative driving under 2k rpms, secondary filter removed...~19.8 mpg

Obviously i'll have to keep track for more than a few tanks, but I saw positive improvement. All the driving conditions were the same, city driving with mixed in highway. Hoping that if I do a drop in AFE Pro Dry S that it'll bump it up ever so slightly more!

 

Time to post this again. They found zero loss in MPG with filters clogged to the point of damaging the intake tubing.

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

There is good understanding why your intake has zero bearing on fuel economy. Modern fuel injection controls the fuel amount precisely, and the throttle plate controls the amount of air going in. Unless you are at full throttle the throttle plate will always be a bigger restriction than the air filter. It's job is to restriction so you control our speed.

You are keeping rpms below 2000 rpm, your air filter isn't even 1/3 of it's max flow, there is no gain by having less restriction when it isn't needed.

 

That is a really cool test, thanks for sharing. I did expect more loss from the carbed car and a small loss from the EFIs, but no. Regardless, you know we'll see another claim here from the next guy who spends a bunch of money on a filter, and the more he spends the better his economy and power will be.

 

Mmmmmm....ok? I guess my slight bump was just MAGIC! I understand the air/fuel component (took combustion in grad school), but the fact is the more air the better. And do you think it's possible that the fuel injector control isn't exactly as dead on as you think? I'm sure it's pretty damn close, but if it's just ever so slightly off at adjusting the amount of fuel it injects, it could be too rich to get complete combustion from the amount of air entering the combustion chamber. It's going to be a very small effect, but what else could possibly explain my increase in fuel mileage? I'm open to other suggestions if you have any since my driving has been exactly the same over the weeks I kept track of it...

 

so you think making your intake tract less restrictive will net more volume in your cylinders?