Air intake tube attachment removal

Was wondering if this is the so called "charcoal filter" and if I can remove it for a little gain. This will make it a little louder and add throttle response because the air doesn't have to fill that up before entering the engine. Thanks

 

I forgot what those cans actually do but im told yes you can remove them and cap off the openings but it wont gain you anything in doing it except removing clutter. I think they are there to maintain steady airflow pressure when you open or close the throttle body quickly

 

Thats a intake harmonic resonator. Dont touch it. From a tirade in another thread, the resonator info is halfway down:



My ears are burning and im running out of popcorn...

Heres the thing, one thing that DP did state that is correct, is that the point of port on the intake tract that the FPR is connected to will not have anything near full vacuum as is measured at the throttle plate. There IS vacuum, and there IS restriction within the intake. You CANNOT state that there is atmospheric pressure inside an intake tract. If you did, then like i said, vacuum leaks would not exist, and the MAF sensors would function like an appendix.

Also i already knew the FPR was on the return side. Most every fuel rail is designed this way. The removal or application of vacuum (depending on setup) restricts the return flow to increase rail pressure (or maintain it as demand will be higher in that instance).

Let me throw in there that CARB would never allow a car into California with any device that had a 'vent to atmosphere' or atmospheric pressure as this has been described here. CARB is the reason we have all this oil vapor shit being recirculated back into out intakes from the PCV and gunking up @CodeSeven 's throttle plate (to bring this thread full circle).

Let me also add that if you do a Google image search for the image you posted form the other thread, with the FPR illustration venting to atmosphere, it does not show up anywhere on the internet other than the thread here on Tacomaworld that DP linked to us. Just sayin......

What DP said was that there is no USABLE vacuum at that point in the intake tract. The question that we must ask is what are we defining as usable vacuum and what is the baseline vacuum measurement for the device running on that vacuum source? Atmospheric pressure does affect the outside air density of the available intake air BEFORE it enters the first restriction in the fuel control system, the air filter (or air box). The moment it enters this space, it is part of the internal combustion system. If you read some German repair manuals, it refers to the area from the airbox to the throttle body as the air/fuel preparation system not the intake. The restriction of the intake tract and the pressure differential created by the pistons moving are two functions of what creates vacuum in the intake tract, completely unaffected by atmospheric pressure from the point of the air box. The distance from the beginning of the restriction to the source is directly proportionate to the pressure differential that will be created at that point. The same way you can take a straw of a set diameter, suck on one that is 1 inch long, then the same one that is 12 inch long, the force required to pull a measure of air will be the same, but the force necessary pull the entire volume inside the 12in straw will be increased based on the total increase in volume and drag from inside the straw, or intake. This is why big ass intakes do not necessarily mean more power, as the same sized engine still pulls the same volume of air.

That being said, we already understand the Venturi effect that this intake will maintain about the same volumetric flow as long the the relative altitude of the intake and the diameter doesnt change. Though if it widens, the flow will slow, if it restricts, the flow will accelerate. For fun lets throw in Bernoulli's Principal that faster airflow moving over a fixed object will create a lower pressure zone. Inversely, an area where airflow is slowed or stagnated will relatively have a higher pressure than the area with faster flow. The basic concept of lift.

I also want to add the function of the 'resonators' as we have been calling them. They work as a result of wave harmonics to contain the resulting pressure waves that are formed from air being slammed against closing valves on the intake tract. They contain these harmonics as to prevent them from excessively slowing the high speed flow of air. If a mass of air slows, it must increase in pressure if it is unable to continue at the same speed into a new space. The intake manifold on any car is also a resonator, where instead of containing the rouge harmonics, as in a helmholtz resonator, it directs them into the adjoining intake runners. Part of Newtons Law states that the air mass will be affected by gravity, causing the slower moving, denser airmass to downwash into the resonators.

Now lets look at the intake tract on our tacoma. Imagine a one cubic inch mass of air on its journey into the engine shaped like a smiley face --->


1. First entry and restriction. Also largest volume segment of the intake. will be pulled in though the air filter, into the high volume, low speed, low density segment.

2. The intake runner, including the MAF. The air mass is at "atmospheric pressure" until it enters this restriction causing the first pressure change by accelerating the in order to maintain the same mass it is replacing as it enters the combustion chamber. According to Bernoulli's principal, this action creates a lower pressure area inside the intake runner. The pressure differential will vary depending on how much volume is entering the combustion chamber, which in turn will require air mass from upstream to replace it. The intake harmonics will create waveforms moving both back and forth through the manifold and the intake tract from the valvetrain as well as the throttle butterfly and IAC valve.

3. Here is that freakin resonator that the FPR hooks into. To take advantage of Newtons law, these attach to the bottom of the intake. Naturally higher pressure will accumulate into these areas as the harmonics from the intake track fill these voids.

4. The throttle body/IAC. This is The Narrow Sea between Westros and Essos. At WOT, the two sections operate as one, with the harmonics generated by the drivetrain extending into the intake tract. Likewise the pressure differential will be more significant coming form the engine at WOT, and proportionally less as the throttle closes. The IAC also generates these same effects but to a much lesser degree.

Here is the key. Air is continuously drawn in regardless of throttle position in order to keep the engine running. Harmonics do not increase in intensity with RPM, only with frequency. So throughout the entire tract, there IS VACUUM, as there is contained high speed movement of air within a space of reducing volume.

The point the the FPR connects will have a higher pressure related to the area outside of the resonator according to Bernoulli's Principal and Newtons Law. The air mass inside of this space will move in and out at a higher frequency in proportion to RPM, but everything that happens will take place as a secondary result of what happens to the air mass rushing towards the combustion chamber, subject to drag, venturi effect, and wave harmonics. You can see this with a vacuum gauge hooked up to the resonators. It will wiggle like you timing is slightly off from the harmonics, but it will definitely be in negative pressure.

Whats been created in this space that the FPR is reading is a new "baseline pressure" not based on whats is outside the engine, but the conditions created by the engine. It will be lower from atmospheric pressure by a few psi, but will allow a baseline for the FPR that does not rely on what altitude you are at for proper function. It will be based on air mass intake the intake.

At higher altitude, you loose horsepower because the engine has to run faster to pull in the same amount of air, and in turn use less fuel per cycle to match the lower O2 content. The vacuum draw on the FPR will stay relative to the vacuum draw at sea level as the same process that i described above will take place and drop the pressure in a similar manner.

 

I don't think 1st gen Tacos have a charcoal filter. What you are showing is the resonator. Removing it and capping it off will make the engine quite a bit louder at higher rpms, but won't affect throttle response because it's upstream of the throttle body.

 

also FYI - the charcoal filter is that box on the drivers side fender well with all the vacuum lines hooked to it and its connected to the vent hose from the gas tank

 

Thank you for all the responses!

 

I removed the resonator on my 3.4, no difference in mileage or performance but it did cleanup under the hood a bit.

 

Soooo.... leave them on?

 

Like said, dont touch them. Someone way above our pay grade decided to put them there.

 

yep, you gain nothing by removing them but it makes the engine a little more air sucky noisy without them.

I think its got some small thing it does to smooth out the airflow somehow but that got way to technical for me to care when I tried to read about what they function to do

you cant see it with the hood closed so unless it bugs you and you want to declutter the engine, just let it be but I don't think removing it will change anything but sucking air noise level

 

I also want to add the function of the 'resonators' as we have been calling them. They work as a result of wave harmonics to contain the resulting pressure waves that are formed from air being slammed against closing valves on the intake tract. They contain these harmonics as to prevent them from excessively slowing the high speed flow of air. If a mass of air slows, it must increase in pressure if it is unable to continue at the same speed into a new space. The intake manifold on any car is also a resonator, where instead of containing the rouge harmonics, as in a helmholtz resonator, it directs them into the adjoining intake runners. Part of Newtons Law states that the air mass will be affected by gravity, causing the slower moving, denser airmass to downwash into the resonators.

Here is the key. Air is continuously drawn in regardless of throttle position in order to keep the engine running. Harmonics do not increase in intensity with RPM, only with frequency. So throughout the entire tract, there IS VACUUM, as there is contained high speed movement of air within a space of reducing volume.

The point the the FPR connects will have a higher pressure related to the area outside of the resonator according to Bernoulli's Principal and Newtons Law. The air mass inside of this space will move in and out at a higher frequency in proportion to RPM, but everything that happens will take place as a secondary result of what happens to the air mass rushing towards the combustion chamber, subject to drag, venturi effect, and wave harmonics. You can see this with a vacuum gauge hooked up to the resonators. It will wiggle like you timing is slightly off from the harmonics, but it will definitely be in negative pressure.

 

You mean a corporate MBA/CMA/CFA/bean counter? Nah, can't be. Those guys tend to delete stuff from our trucks.

The Toyota engineer who specified the resonator may have been tasked with keeping the engine as quiet and as smooth as possible - there may be no right or wrong answer, just different design objectives.

@kLeibow Looks like the resonator is secured with just a hose clamp? You can always experiment with removing it and capping it off. See if you like the sound. Just be sure it's sealed tight to avoid tripping a CEL and setting a lean code.

 

if you do remove it, use a pvc pipe cap to reseal it with, they cost about 50 cents