Multi Cyl into one exp chamber

[Fastjeff57]

Okay, okay! So they're FOUR strokes, but the principle is the same.

Jeff

[Powerabout]

Okay, okay! So they're FOUR strokes, but the principle is the same.

Jeff

Not so sure about that...a collector drags the gas out better than 1 pipe would but we know a single pipe on a 2 stroke makes more power for other reasons
Much better blow down on a 2 stroke than a 4 so less of an issue.

[Fastjeff57]

Acoustically speaking--and this is what it's all about--the action is similar.

Jeff

[Powerabout]

Acoustically speaking--and this is what it's all about--the action is similar.

Jeff

I'm not with you..
a 4 stroke collector creates a low pressure to pull the adjacent cylinder down and after that who cares
pulling the exhaust out of a 2 stroke is not a problem its pushing it back in thats the art of it, not something you need to do with a 4 stroke

[Fastjeff57]

ACOUSTICS--that's the thing here. Two or four stroke, exhaust pulses are being used to draw exhaust out (and air in). Be it an expansion chamber, megaphones, or the simplest form (drag car headers) the acoustic principle is the same.

Jeff

[Powerabout]

ACOUSTICS--that's the thing here. Two or four stroke, exhaust pulses are being used to draw exhaust out (and air in). Be it an expansion chamber, megaphones, or the simplest form (drag car headers) the acoustic principle is the same.

Jeff

ok yes, its all about sound waves

[champ20B]

ok yes, its all about sound waves

My brother's Polaris 1200cc jet ski is a two cycle (3 cylinder) engine with 135hp. It has ONE expansion chamber! I replaced the brain box and rebuilt the three carbs on this engine.

[Powerabout]

My brother's Polaris 1200cc jet ski is a two cycle (3 cylinder) engine with 135hp. It has ONE expansion chamber! I replaced the brain box and rebuilt the three carbs on this engine.

Nothing special, that makes a2.4ltr 270hp?

[champ20B]

Nothing special, that makes a2.4ltr 170hp?

No, 1200cc is about 75 cubic inches. That is a (1.2) liter w/135 horses.

At 2.4 liters that would equate to 270bhp if one looks at it for relative power per displacement. That's pretty impressive for a standard production engine! But it is an odd cylinder # with one chamber. I have heard that three cyls don't usually need a chamber because of the pulses from each other makes up the needed resonation. It appears that there was an engineer that thought differently.

[Revengable]

The tri-Y type headers are an attempt at equal distances..