air intake pocket

Now, that's what I call hidden storage!

 

If it's what I think it is, it's an intake resonator. Many cars have them. Not 100% sure on the theory but here's what I remember:

Air intake is not smooth, it tends to be rapid pulses because of the action of the intake valves. The intake can be tuned to maximize certain frequencies of the pulses to help with air flow at certain speeds by adding air chambers of specific sizes, thereby improving power at specific RPMs. It's usually done to smooth out power curves at specific RPMs. It's the other side of adding a tuned exhaust.

Someone correct me if I'm wrong please. (they always do).

 

The engine gulps air in pulses. The box is designed to provide one pulse without causing much of a vacuum. Yes, it's a resonance chamber. It dampens the pulses by the above mechanism so you don't hear them (much).
In the Prius the box also takes some of the air forced back out of the intake due to the "Atkinson cycle" (intake valves are held open during part of the compression cycle).

But the short answer is narf is correct, it's an intake resonator, there to smooth air flow to reduce noise and smooth out air flow.

 

Hey - my Prius has a CAI!

 

Most Toyotas have some form of resonator built into the intake tubing. It also has another nice effect, if you should accidently hit deep water (an unexpectedly deep puddle) the resulting splash into the air intake can allow water to be sucked into the engine. The resonator box allows for the greater volume of water to be pulled down by gravity and help reduce the chances of hydrolocking the engine. Small amounts of water can be handled, but a large gulp can enter the combustion chamber and cause massive failure.

 

wow, those Jeffries tubes are getting smaller and smaller! :fear:

 

so... what would happen if you were to add a snorkel... hehe... you can get as high as.. what?.. the plugs? the bottom of the fuse box?

 

A snorkel would change the tuning of the intake system. I doubt that it's critical, so it probably wouldn't hurt. It would certainly help those who drive into "ponds" on the road.

 

its the intake resonator, i removed mine on both priuses, it just increased the noise from the intake not by much.

 

He expected it would improve power and/or fuel efficiency. But one fiddles with resonant systems at one's peril: if the remaining air intake structure resonates in the wrong way it can reduce power and/or fuel economy. Impedance is not the same thing as resistance.

 

My white resonate bottle/tank was crushed in a wreck ...so do I really need one? Would a gallon milk jug work or something like that ? Statultra did you find any improvements by leaving it off??

 

hearing about all the incidents, maybe toyota decided to give a little access port for all the mice to be nice to them

 

No. It needs to be exactly the same size and shape.

Tom

 

As long as you have the connection to it sealed off you probably don't need it.

When doing intake mods to other Japanese cars I've removed resonator boxes (actually disconnected them, but left them in place.) One car used MAP sensing the other was a mass air flow sensor. Both used air horns with conical K&N air filters. Neither had any problems and both produced a lot more power than before (timed 0-60 runs), but this was because of the air horn/filter, not the lack of resonator. The one negative is that the Accord was noisier, particularly when the VTEC kicked in. The 240 sounded much better (throatier but in a positive way) without the resonator. Gas mileage was unaffected...except for the tendency of a certain driver (me :redface to use the new power available frequently for harder launches.

It would be interesting to do a test on the Prius making a fixed distance highway run (in both directions) on cruise control with/without the resonator measuring both mileage recorded and time elapsed--the latter as a cross check.

 

Hmmm. That looks interesting. Could we add a little electric fan to that box and pressurise the intake air?

 

It would take a little more than a "little electric fan" to pressurize the intake air. You have to make the pressure higher than what the engine does, not just over what it is when the engine is not running.

 

Well, the gasoline engine certainly will function without that part. If you want to do a first-class restoration like jelloslug, then you will replace it. If you are working to a lower standard, then leave it out.