Do I really need this resonator box?

Messages
12,424
Location
Phoenix, AZ
Thread starter
Intake air hose on my Camry broke, so I ordered a new Dorman one. There's a resonator box underneath it with a hose that goes to it, the hose had a hole. I couldn't find an aftermarket replacement hose, so I called the dealership. They want $76 plus tax for the hose. Not gonna happen for a beater-commuter car. I went to Home Depot and bought a 1-1/4" plug and a hose clamp for $3, fits perfect. Took out the resonator box, is it really necessary? What does it do, I'm guessing sound dampening? I drove it around the block, power is the same and so is sound, maybe a tiny bit louder, but I really don't think so.
 
Messages
10,634
Location
Phoenix
Yep, it's just a muffler. I would have done exactly what you did and enjoy a little more growl out of the engine at WOT.
 
Messages
12,424
Location
Phoenix, AZ
Thread starter
Originally Posted By: Merkava_4
What's that box on the left side of the 1st picture where the spark plug wires are going over ?
You mean the valve cover?
 
Messages
1,462
Originally Posted By: Colt45ws
The resonator is purely for sound dampening. It will not hurt power or economy one bit.
WRONG. They are also used to tune the intake air impulse to increase midrange torque per toyota.
 
It looks like the plug might be long enough to extend into the intake tube. If so you might want to trim it back, you don't need any added restrictions or turbulence. As said these boxes are used to tune in or out resonant frequencies in the intake impulse as well as noise control. You'll lose a little something without it, Toyota went to some trouble to gain that wee bit of torque or mpg. Aftermarket intake tubes eliminate these boxes (K&N, Airaid, etc) all the time and claim gains but they're also smoothing the pipe by eliminating the connection.
 
Messages
12,424
Location
Phoenix, AZ
Thread starter
Originally Posted By: AZjeff
It looks like the plug might be long enough to extend into the intake tube. If so you might want to trim it back, you don't need any added restrictions or turbulence. As said these boxes are used to tune in or out resonant frequencies in the intake impulse as well as noise control. You'll lose a little something without it, Toyota went to some trouble to gain that wee bit of torque or mpg. Aftermarket intake tubes eliminate these boxes (K&N, Airaid, etc) all the time and claim gains but they're also smoothing the pipe by eliminating the connection.
the plug doesn't go much further past the hose clamp, still plenty of room before it impedes air flow in the tube. I'll keep an eye on power/noise/fuel economy and see if I notice a difference.
 
Messages
31
Location
maryland
It will run fine without the resonator, but you will lose power and volumetric efficiency at certain rpms. The pressure wave caused by the intake valves closing will now slow down the intake air.
 
Messages
4,599
Location
Manchester, England
Originally Posted By: dishdude
I want to know how what box does anything for power.
There are effects to increase the V.E on N.A engines. As with most tuning, this Intake tuning can be a compromise and only truly effective over a certain RPM range, but picking a choosing the design to fit in around the engine, the "boost" given can be used to smooth out the output over the engine. Tuning can be done via the length of the intake runners, and their size. Long thin intake runners will speed up the gas velocity and the momentum of the fast moving air will help pack the cylinder full even as the intake valve is closing. This will boost power at lower engine speeds, but the thin runner design will restrict airflow at high speeds. Tuning and resonance of the pipework will also help. As the engine sucks in air, there are pulses of high and low pressure. The tuning is designed use these pulses of pressure to get more into a cylinder, by adjusting the size and length of the intake. This effect is known as Helmholtz Resonance. The resonance effect will only work in a given intake size as a specific RPM range, so this can either be used to remove a flat spot, add extra torque in lower RPMs where most day to day driving occurs, or a variable length Intake system can be used to provide two resonant effects at different RPM ranges. An example of this is the BMW DISA flap in some manifolds.
 
Messages
3,996
Location
United States of America
Olas, jaw to the floor as your post flies right over my head. I assume you are referring to the intake version of scavenging. Top Fuelers use this I think to actually pull air out of the headers.....much like an exhaust fan in a warehouse is 'better' than a regular blowing fan. Also, two-strokes can tune the powerband by changing the expansion chamber so they can ride the fat part of the powerband (or the highest). It is still kind of new tech-like twenty years old as n the early nineties they used alot of regular round air filters which did nothing to 'pressurize' the intake charge. Although, I think Japan has been at it for awhile since they were making small fours and us Americans were putting around in big, lazy V-8s.
 
Messages
10,060
Location
Central Washington
Basically, the resonator is an 'air spring'. When the intake valves close, the air wants to keep going but runs into it and reflects off the valve. The air pressure wave travels into the resonator and reflects back. This is how it dampens sound. But, if you were doing it right, you could use this reflected wave to 'push' more air into the cylinders, increasing volumetric efficiency. It would only be effective at certain RPM ranges as the distance from the intake valve to the resonator is timing of the reflected air wave. It has to arrive while the intake valve is open. Longer distance means its effective at lower RPMs. This is why truck intake manifolds are often longer as the longer runner increases the volumetric efficiency at a lower RPM due to this effect. If you look at a old Ford 4.2L V6 in a truck, it technically had two intake manifolds. There was a long/thin runner and a short/fat runner to each cylinder. The short/fat runner was normally blocked off by a throttle-plate type system. At low RPMs, the engine pulled its air through the longer runners, which has a longer interval for this 'forced air' effect, so better torque. Once the engine crossed over, I think it was 4K RPM, the PCM opened the short runners to increase top end HP via this same effect. I personally think the resonator box is on the wrong side of the throttle body to be effective except at WOT, maybe, but its also pretty far away from the intake valves.
 
Last edited:
Messages
42,565
Location
Ontario, Canada
Originally Posted By: Olas
Originally Posted By: dishdude
I want to know how what box does anything for power.
There are effects to increase the V.E on N.A engines. As with most tuning, this Intake tuning can be a compromise and only truly effective over a certain RPM range, but picking a choosing the design to fit in around the engine, the "boost" given can be used to smooth out the output over the engine. Tuning can be done via the length of the intake runners, and their size. Long thin intake runners will speed up the gas velocity and the momentum of the fast moving air will help pack the cylinder full even as the intake valve is closing. This will boost power at lower engine speeds, but the thin runner design will restrict airflow at high speeds. Tuning and resonance of the pipework will also help. As the engine sucks in air, there are pulses of high and low pressure. The tuning is designed use these pulses of pressure to get more into a cylinder, by adjusting the size and length of the intake. This effect is known as Helmholtz Resonance. The resonance effect will only work in a given intake size as a specific RPM range, so this can either be used to remove a flat spot, add extra torque in lower RPMs where most day to day driving occurs, or a variable length Intake system can be used to provide two resonant effects at different RPM ranges. An example of this is the BMW DISA flap in some manifolds.
Another is Ford's variable runner system they used on the 24V Duratech V6 and 32V Modular where "flaps" in the runners would control whether the air took the short route or the long route to aide in low end torque. My question to you would be with respect to the OP's setup, how significant can the effect be when discussing variables in intake tract design significantly BEFORE the throttle body (where this resonator was, and well ahead of it) vs the rather obviously significant role of those behind it like the manifold design itself, and its variable runner brethren. Somewhat answering my own question but BMW used tuned horns on the M5, one for each throttle body, which drew from a common (and massive) plenum that pulled from two large intake tubes that led to their own air filter assemblies. Obviously the horns were there to increase velocity and smooth power delivery at lower RPM's but I would doubt that the rest of the design past the plenum would have much of an effect, as most of it would be from the horns. The throttle body itself is of course a regulated restriction and has a necessary effect on airflow. It wold also affect the smoothness of the air delivery, which would be most dramatic at lower throttle openings and be the least dramatic at WOT, which, IMHO, would be where anything upstream of it would have the chance to be the most effective. IMHO, given the location of the OP's resonator, I can't see its contribution on the power side of things being significant. On the other hand I could see it reducing part throttle intake tract noise and, again IMHO, is likely what its role was here. Great post BTW thumbsup
 
Messages
4,605
Location
The Garden State
Originally Posted By: OVERKILL
IMHO, given the location of the OP's resonator, I can't see its contribution on the power side of things being significant. On the other hand I could see it reducing part throttle intake tract noise and, again IMHO, is likely what its role was here. Great post BTW thumbsup
+1, My 1996 Zetec 2.0L Contour has a resonator box and it was explained to me years ago that it was to quiet intake noises. Whimsey
 
Top