[Trevor]

Harvey, reference your post #38.

You commenced your own crap game with your abusive post #26. You now excrete more of the same and continue with a continued “litany of lies” in the form of childishly worded text, devoid of sense and diction.

I have correctly explained the principle involved in an exhaust system. You now make a series of wrong statements all directly misinforming readers.

This is right, the gas plug that is released when the exhaust valve opens, has a pressure of about 65psi.

Quoting a figure intended to impress is meaningless and confusing, due to there being considerable differences between engines.

This gas pressure has to push the gas in the pipe in front of it. So the gas plug has a pressure front. As this plug travels away from the cylinder, it pulls a low pressure behind it that is maintained till the inlet valve opens, to start the inlet gas moving into the cylinder.

An existing low pressure area which follows each gas plug, is available before, and is maintained after the inlet valve opens, in order to facilitate flow via the inlet port. This is in fact the crux of principle involved. Overlap between the opening of the inlet valve and the closing of the exhaust valve, is specifically included in order to facilitate this action.

It is equally important to reduce this gas plug pressure in the pipe as soon as its usefulness is over, we can’t wait till it reaches the end of the exhaust pipe, so we fit the Resonate chamber where the gas plug can expand to reduce the gas pressure, just like (as if it had) it reached the end of the pipe.

The gas plug/pulse, must be allowed to expand immediately after it has travelled a given distance, within a given diameter of pipe, this configuration having been arranged to suite each individual application and comprises the “tuned length.” When the pipe must exceed this desired length, this is terminated in an expansion chamber, which can serve a double purpose and can also function acoustically. Hence the finally sorted confusion in descriptions, within this thread.

This is the gas inertia being used, to increase the Volume Efficiency of the engine, as you say. The US have lagged behind the others by producing larger capacity engines that produce good torque at low engine speeds. So they have not had used the resonate theory like the Japanese or Europeans, to produce the torque at higher engine speeds.

Where can this “resonate theory” be confirmed as an established theorem?

The evidence presented is completely contradictory and is self conflicting. It is stated that the system is used at higher engine speeds, but then it subsequently stated it is not suitable when 4,500 RPM is exceeded.

This has been used on engines that produce the Torque under 4500rpm. It loses it usefulness after that speed, as the gas plug only has a speed of about 300ft per sec. So as the engine revs faster, the low pressure it the cylinder, cannot be maintained till the inlet valve opens. It is occurring earlier, when the piston in rising on the exhaust stroke, so we lose the benefit of its help in increasing the VE.

There is no physical limitation in respect of the speed of the gas and most certainly no definitive figure can be applied. In actual fact the principle covered here, is best suited for applications involving relatively high RPM.

The speed of the gas plug is in no way limited and depends only upon, the cross section of the pipe and length before the first point of expansion; engine speed, compression ratio, and valve overlap. The principle was most widely used in the past, in engines providing power at relatively high RPM, e.g. racing engines.

The limiting factor has been the width of the power band over which the action involved can be made effective. In later years greater understanding has enabled improvements, so that the system is able to be used in common road cars, with the exhaust and intake being treated as a whole.

The SVX uses this gas plug to lower the cylinder pressure as the piston is reaching its maximum speed at about 80* ABDC. Reducing the pressure here reduces the power loss, by the piston having to push against a pressure. To get the low pressure in the cylinder that we need to start the inlet flow, we use sound waves (and just for Trevor) or acoustic waves.

This statement is completely beyond sense and comprehension. The exhaust valve is open throughout the exhaust stroke, any pressure which could exist, would be caused by by resistance within the exhaust tract. The inertia of gas already in motion, generates a continuing waves of negative pressure within the exhaust tract.

N.B. In order to use the expression “sound waves” in this context, it is absolutely necessary to explain exactly how waves of sound, rather than pulses of gas have inertia. The explanation will be awaited by many and will provoke considerable interest.

When the exhaust valve opens besides the gas pressure, a positive sound wave is released to travel down the pipe, at about 1600 ft per sec. When this reaches the end of the pipe, it expands into the atmosphere, to be replaced with a negative wave that travels back up the pipe, to reach the cylinder as the inlet valve opens. It then travels up the inlet tract to start the inlet sequence.

As the length of the pipe affects when the negative pressure will arrive back at the cylinder, we can’t just use the end of the pipe so we use the resonator to do the same job for the sound waves, as it does for the gas plug, imitate the end of the pipe.

Pockets of negative pressure follow each and every plug/pulse of gas. Both flow in only one direction, i.e. onwards and outwards from the exhaust valve. Nothing in any shape or form “travels back up the pipe”.

When the inlet valve opens, a low pressure area is in existence behind the pulse/plug of gas which at that point is leaving the exhaust port and thus has inertia. That pulse in turn is assisted by the inertia of the preceding pulse, there being several travelling in unison.

So the SVX design uses the inertia theory to reduce pumping losses and the resonate theory to raise the VE.
Best of both worlds.

Inertia theory, resonate theory, pumping losses. These are the simplistic, inaccurate words of the illiterate. Just where can these theories be qualified in respect of an engine exhaust system?

For absolute confirmation in respect of my statements, as well as a simple explanations in layman’s terms, refer as below and in paricular take note of, “The Exhauxt Pulse,” as well as, “Resonators.” ---

http://www.nsxprime.com/FAQ/Miscella...austtheory.htm

Also here. ---

http://www.sideways-technologies.co....?m-1201221799/