回壓喉加個perssure chamber有咩用

It ( about 2 inches long with fins ) cools the exhaust gas returning to the tank and therefore cools the fuel.

Your tank of fuel will therefore run longer - more fuel efficient.

Pressure chamber ( like a big filter ) is something different.

Nothing here will cool down the engine.

http://www.amainhobbies.com/product_info.php/products_id/1741

Pressure chamber is to stablise tank pressure - ie pressure into the engine.  Some people will run very long fuel line at the same time.... Think of it as a big air cushion.  If you can tell the difference, you are a very good RC player!!

I really cannot see how exhaust cooler can reduce temperature of the engine and make the engine run faster.  Even NovaRossi has not make such a claim.

Exhaust cooler is not the same as pressure chamber.

Exhaust cooler: see this http://www.novarossi.com/content_uk/products/gadgets/index.php

Pressure chamber : see link in my previous post.

I need to dig out my physics text book - since when the location of an 'air' chamber will affect pressure.  I think it is the length/diameter of the fuel line that affects pressure, the longer the line, the more pressure drop and smaller diameter, higher pressure?