Chaz...designer...inventor...engineer

[Chaz]

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want to learn about the 4 strokes (as well as the 2 strokes) also....

has anyone tried putting a Japanese 4 cylinder alum car engine, supercharge it and bolt onto outboard mid+lower?

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Don't know about hanging one on the outside , but they seen to work pretty good laying down on the inside ...

[AZMIDLYF]

[AZMIDLYF]

Supra motor? Never heard one loping like that though...especially with a turbo.

[Chaz]

#1 ) Can someone name the five basic components of an "expansion*chamber" ?

#2 ) Can someone explain the function of each component ?

#3 ) Can someone name the two basic components of an outboards exhaust ?

#4 ) Can someone explain the function of each component ?

#5 ) Can someone identify any overlapping functions of these components ?





* The use of the words "expansion*chamber" is meant for identification purposes only . Any further use of these words , be they expressed , written or implied , must have written permission in triplicate form from torque engineering , erv kanamoto , stuart toomy , kel carruthers , spec 2 and daryl bassani ...

[AZMIDLYF]

Warden has me on task today but, I will give the "expansion chamber" a noob shot.

Chamber has 2 cones: divergent & convergent, angles and lengths of cones play into timing of waves, inlet and outlet pipe sizes guessing also play roles. Divergent cone expands flow and creates a low pressure wave back to port to draw out more exhaust, convergent cone compresses flow and sends a pressure wave back to port at the right time to keep the incoming fuel/air from exiting the exhaust port. Macro world here of course...

[vnemous]

1. very dry ricotta
2. granulated sugar
3. vanilla
4. Chocolate chips
5. Cannoli shells

[AZMIDLYF]

No bribing the teacher.

[vnemous]

It will make his chamber expand

[AZMIDLYF]

2 stroke or 4?

[vnemous]

You guys keep talking about Wardens and its is making me feel like Im back at work

[noli]

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#1 ) Can someone name the five basic components of an "expansion*chamber" ?

#2 ) Can someone explain the function of each component ?

https://en.wikipedia.org/wiki/Expansion_chamber


Arbeitsweise_Zweitakt.gif




I'm not sure but I will give this a shot. The five components are listed below. This is not complete and may contain errors.
Please show same concepts on an outboard motor.


The Expansion chamber depicted

(1) Divergent Section(diffuser). This section increases in diameter. Creates a negative pressure which aids in the sucking in
fresh fuel mixture into cylinder. Brings the exiting exhaust pressure to near-atmospheric level.

(2) (3) Convergent section. The Diameter gets smaller and smaller. This section reflects back a series of acoustic pulses back
to the cylinder. These pulses arrive in a timed manner (thus the reason why this is called a tuned exhaust) back to the
header and cylinder to push back any fresh mixture drawn into the header because the exhaust port is still open during
the compression stroke. A strong acoustic wave (yes, sound!) encountering a decrease in area will reflect a strong acoustic
wave in the opposite direction.

(4) (5) The diameter of the exhaust header and exhaust tail pipes are calculated with a specific formula to aid
in the tuning of the 2-stroke exhaust system.

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[noli]

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The link below are instructions to building your own 2-stroke tuned-exhaust pipe. Not really relevant here, since I really would like to see these concepts on an outboard motor.
This is not an easy task, thus you will also need to feed your brain with energy (see pics of canolis, sausages, pasta, etc throughout this thread )

Just for fun reading ==> http://www.instructables.com/id/Buil...or-a-2-stroke/










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[noli]

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home-made external expansion chamber.










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[AZMIDLYF]

Wow, I think my Readers Digest version was pretty spot on.

[noli]

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#3 ) Can someone name the two basic components of an outboards exhaust ?

#4 ) Can someone explain the function of each component ?

I'm gonna try, and again please correct/add where necessary



The two parts of the outboard exhaust system are:
1. the exhaust cavity in the engine block connected to the adaptor plate
2. the can with the exhaust tuner attached at the top of the can's exhaust cavity

The resonance from the exhaust chamber and tuner (and maybe the water that begins mixing inside the exhaust chamber in the can) are all playing a part in tuning the exhaust to lessen scavenging power from the exhaust port while fresh fuel mix is beginning to exit the exhaust port.

The length and diameter of the tuner plays a part in "Tuning the Exhaust" principle. I watched this video and it explains how to increase the power band by increasing the exhaust port. But not sure if anyone tried this on an outboard and what their results were:








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