A question for any piston heads out there.

[neobart]

I've come across something that has me quite puzzled. On my carb for my .21 LRP, I have three different inserts. 7.5, 8.5 and 9mm. But at the bottom of the carb neck where the inserts meet the carb, the opening is only as big as the smallest insert. :?

How can the performance be any different when the opening in the carb can never be bigger than 7.5mm?

 

[Blitzkrieg]

the insert is what is actually what is changing the performance its limiting the amount of air that is able to flow into the carb..

 

[jetmechG550]

Venturi

 

[Blitzkrieg]

Venturi

yea what he said