What does an expansion pipe do?

On a two-stroke engine, an expansion chamber or tuned pipe is a tuned exhaust system used to enhance its power output by improving its volumetric efficiency.

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Regarding this, how does an expansion pipe work?

The basic idea behind an expansion chamber is to use the momentum and pressure of the exhaust gases to create a pump that squeezes more air and fuel into the cylinder during the intake stroke. It does the same sort of thing that a turbocharger does, but it does it without moving parts.

Also, do 2 strokes need back pressure? In a piston-ported two-stroke engine, however, the situation is more complicated, due to the need to prevent unburned fuel/air mixture from passing right through the cylinders into the exhaust. The exhaust port opens while there is still significant pressure in the cylinder, which drives the initial outflow of exhaust.

Also to know is, why do 2 strokes have big pipes?

Simply put, it's because the two-stroke exhaust system, commonly referred to as an 'expansion chamber' uses pressure waves emanating from the combustion chamber to effectively supercharge your cylinder. Early two strokes had straight pipes, a simple length of tube attached to the exhaust port.

Can you run a 2 stroke without exhaust?

2-strokes run fine without mufflers, if your muffler pipe is an expansion chamber you might notice a low to medium power loss, but you should be fine.

Related Question Answers

What is a tuned pipe?

A tuned pipe is a part of the exhaust system of some two-stroke engines. Tuned pipe can also mean: In automotive engineering generally, the tuned exhaust system of a car or motorcycle engine.

What is engine back pressure?

Engine exhaust back pressure is defined as the exhaust gas pressure that is produced by the engine to overcome the hydraulic resistance of the exhaust system in order to discharge the gases into the atmosphere. The term back pressure can be also spelled as one word (backpressure) or using a hyphen (back-pressure).

How hot does 2 stroke exhaust get?

Depending on where you take the temps, between 150-250 deg F.

How does a 2 stroke silencer work?

A two-stroke pipe uses its reflective pressure wave to keep the fuel/air mixture inside the combustion chamber. Most of this tuning is done in the pipe itself, but muffler length and diameter play a part. There is no power difference between one brand's high-end and low-end pipes.

How does a megaphone exhaust work?

With a megaphone, the exhaust stream enters the megaphone at the inlet, and begins to expand at a rate which is controlled by the flare of the megaphone shape. As the exhaust stream expands, it gains pressure as it loses velocity in the larger volume of the megaphone(Bernoulli's Principle).

Can I put a 2 stroke exhaust on a 4 stroke?

2 stroke mufflers are NOT meant for 4 Strokes. will it work yes. but there are different packing's for 2 and 4 stroke. If you do put this thing on a 4 stroke please repack it with the 4 stroke packing. you will start a fire if you don't.

Which type of exhaust pipe is used on a 2 stroke engine?

On a two-stroke engine, an expansion chamber or tuned pipe is a tuned exhaust system used to enhance its power output by improving its volumetric efficiency.

Why do two strokes sound different?

The real reason why 2 strokes are louder is based on the mechanics of the stroke, and the build of the engine. Automobiles (mostly) are 4 stroke. The engine covers the combustion chamber in a water jacket to cool it, which also greatly reduces sound.

What is a 2 stroke power band?

"Powerband" is the HP/torque curves of any engine. The sudden hit of a 2-stroke that people refer to as "hitting the powerband" or "coming on the pipe" happens when the engine hits its sweet spot. 2-strokes rely on the frequency of waves. Notice how the exhaust of a 2-stroke is shaped.

How does a motorcycle exhaust system work?

In a four-stroke system, as the exhaust valves begin to open, a pulse of exhaust pressure enters that cylinder's header pipe. It is a positive wave, which stuffs exhaust gas back into the combustion chamber, back through the intake valves and into the intake system.

How does dirt bike exhaust work?

Inside your dirt bike muffler or silencer is the exhaust core, which is a tube with holes in it and is often covered in steel wool on newer pipes. The purpose of exhaust packing is to absorb as much of the sound waves coming from the combustion of the engine as possible.

Why are 2 stroke engines banned?

Two-stroke engines do not use fuel efficiently, so you would get fewer miles per gallon. Two-stroke engines produce a lot of pollution -- so much, in fact, that it is likely that you won't see them around too much longer. The pollution comes from two sources. The first is the combustion of the oil.

Why are 2 stroke engines so loud?

There are two major reasons: Most loud 2 strokes are air cooled and air cooled engines lack the sound dampening created by the water jacket. Because 2 strokes don't have a dedicated exhaust cycle, their exhaust pipes need to be very free flowing in order to clear the cylinder in the short amount of time available.

Why are 2 strokes more powerful?

Typically, a 2-stroke engine creates more torque at a higher RPM, while a 4-stroke engine creates a higher torque at a lower RPM. That being said, 2-stroke engines are more powerful. Two-stroke engines are a much simpler design, making them easier to fix. They do not have valves, but rather ports.

What happens if you don't have enough back pressure?

The classic symptoms of too much backpressure include things like a lack of high speed power, poor fuel economy and even overheating. Anything that backs up exhaust pressure into the engine will also back up heat.

Does a car need back pressure?

As the pulses move along, they generate an exhaust flow. If you have a restrictive exhaust system, it can generate back pressure that works against the positive flow of the exhaust gas that's trying to exit your vehicle. However, a little back pressure is a good thing. In fact, it helps.

What is back pressure in condenser?

High Condenser Pressure Turbine exhaust back pressure is directly related to lost power output to the generator that converts mechanical energy to electrical power. Excess back pressure means reduced efficiency and dollars wasted.

How do I calculate back pressure on my exhaust?

You will need the velocity of flow in the pipe to substituted in the above link.

1. Mass flow rate of Exhaust gases = <mass flow rate of air> + <mass flow rate of fuel> From that Calculate Volume Flow rate of Exhaust gases (Q) and then use the formulae.
2. Result:
3. Back Pressure = Atmospheric Pressure + Pressure Drop.

Does back pressure increase torque?

Back pressure affects torque because it gives us an idea of velocity in the exhaust tubing. Basically a higher velocity (to a point) will have a higher momentum out of the exhaust system. At the head port this high velocity will help pull fresh intake charge in during the overlap period.