Can Anyone Explain This Part of the Stock Air Intake?
- Thread starter SSTJ
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I have heard a couple explanations a air reservoir for when the throttle is first cracked open or it could be to reduce intake noise. If you install a cold air intake they increase noise.
To the average hot-rodder, intake resonators go on the same pile as smog pumps, catalytic converters, exhaust gas recirculation valves and charcoal canisters. But imagine which pile the resonator would end up in if that same customizer knew it was more than a plastic muffler — it's actually an important part of the engine's intake system, and may add a fairly significant amount of horsepower.
To the average hot-rodder, intake resonators go on the same pile as smog pumps, catalytic converters, exhaust gas recirculation valves and charcoal canisters. But imagine which pile the resonator would end up in if that same customizer knew it was more than a plastic muffler — it's actually an important part of the engine's intake system, and may add a fairly significant amount of horsepower.
Not mine but his:
WRITER BIO
Richard Rowe has been writing professionally since 2007, specializing in automotive topics. He has worked as a tractor-trailer driver and mechanic, a rigger at a fire engine factory and as a race-car driver and builder. Rowe studied engineering, philosophy and American literature at Central Florida Community College.
Design and Construction
The resonator itself couldn't be simpler in design; it's basically just an expansion chamber or wide spot in the otherwise-smooth intake pipe. It may or may not contain some kind of baffle or plate, depending upon the design and the intent of the designers. Resonators come in two types: In-line resonators are open chambers that sit in the intake tube, while side-branch resonators are chambers that sit next to the tube and are connected to it via a small duct orTo the average hot-rodder, intake resonators go on the same pile as smog pumps, catalytic converters, exhaust gas recirculation valves and charcoal canisters. But imagine which pile the resonator would end up in if that same customizer knew it was more than a plastic muffler — it's actually an important part of the engine's intake system, and may add a fairly significant amount of horsepower.
Design and Construction
The resonator itself couldn't be simpler in design; it's basically just an expansion chamber or wide spot in the otherwise-smooth intake pipe. It may or may not contain some kind of baffle or plate, depending upon the design and the intent of the designers. Resonators come in two types: In-line resonators are open chambers that sit in the intake tube, while side-branch resonators are chambers that sit next to the tube and are connected to it via a small duct or channel.The Common Misconception
Most hot-rodders and car enthusiasts think of intake resonators as simple mufflers in the intake tube, devices designed to siphon all the awesomeness out of a car's sound track to appease soccer moms and senior citizens. That makes it a prime candidate for the "chuck-it" school of auto modification. After all, it's basically just a plastic tumor growing off of a tube that should by definition be as smooth and blemish free as possible. While sound control is indeed part of the resonator's job, the sound control itself is really more of a side effect of its primary purpose.Pressure Wave Harmonics
Air flowing into your cylinder head's intake port doesn't move in a straight line while the valve is open, then politely stop in its tracks to await another valve opening. When the valve closes, the moving column of air slams into it, then compresses and bounces back like a spring. This pressure wave travels backward at the speed of sound until the intake runner opens up or it hits something, and then it bounces back toward the cylinder. This is the "first harmonic." The pressure wave actually bounces back and forth two or three more times before the intake valve opens again.Intake Tube Pulses
The resonator in your intake is technically known as a Helmholz resonator, an acoustic device used to control pressure wave harmonics. Air bouncing back out of your engine and into the intake tube doesn't do it in a single pulse the way it would in a single intake runner; the multiple pistons put out pressure waves at their own intervals, and some of those are going to try to bounce back in while others are going out. The result is a "clog" or high pressure area in your intake tube that ultimately limits airflow through almost the entire rpm spectrum.The Resonator
Adding an expansion chamber to the intake tube forces air coming back out of the engine to slow down to fill the cavity, thus expending a great deal of its energy and slowing the pressure wave reversion. This slowdown allows fresh air to flow toward the engine without fighting pressure reversion waves the entire way, thus aiding in cylinder filling. Since these pressure waves are essentially sound, giving them a place to expend their energy before exiting the air filter box ends up dampening the intake noise and quieting the engine. Thus, the resonator helps to make the engine paradoxically quieter and more powerful.Not mine but his:
WRITER BIO
Richard Rowe has been writing professionally since 2007, specializing in automotive topics. He has worked as a tractor-trailer driver and mechanic, a rigger at a fire engine factory and as a race-car driver and builder. Rowe studied engineering, philosophy and American literature at Central Florida Community College.
It’s a Helmholz resonator chamber, and it’s a way for engineers to tune the intake system so that pressure waves are not timed so that a low pressure coincides with valve opening. Similar to an expansion chamber on a two stroke engine, but on the intake side. The problem with them is that they only work in a narrow RPM band or bands. A variable volume chamber that changes with RPM could help. I’ve heard of some prototypes over the years, and I wouldn’t be surprised if some design actually made it to production some time.
Turbo City used to make an intake for the TJ. I called and chatted with them about it and was told that the designer was very good and could "see" air. All I wanted to know was why so many of my buddies who installed one could no longer maintain the same speeds going up to Big Bear that they used to be able to do before the swap. I got my answer.
OP
Geezzz guys..its for the mice & rats make their beds. Far as "seeing" the air..Id imagine if he was living or inventing his gizmos in San Berdo.