[Honclfibr]

Originally posted by ancosta
The throttle body is the mechanism where air comes in from the air filter and into the intake manifold.

In an TBI, or throttle body injection setup, the throttle body functions like a carb, as the fuel injectors sit in throttle body, and the air/fuel mix is sent into the manifold.

Today virtually all manufactuers (of cars and bikes) use "port" fuel injection, otherwise called EFI. Air is routed into the intake manifold, where it is mixed with gas via fuel injectors. The atomized mixture is then routed into the combustion chamber to be burned.

Bigger is not better with throttle bodies. They have to be matched according to several factors, including: fuel injector size, pressure regulator & fuel pump rates, intake port length & size, cam size & timing, ignition timing, exhaust flow, head port flow, etc. etc. etc.

All parts of the fuel system should be matched to yeild a stoichiometric (fancy word for 'ideal') air:fuel ratio. For gas engines, the ratio is 14.6 parts air to 1 part gas. This condition will lead the fuel and o2 to be completely consumed, resulting in more efficiency, power and reduced emissions.

In my exerience it's generally best to use a proven combination of parts, usually selected by the manufacturer, aftermarket tuner, or otherwise "wicked smaht" person.

You, sir, are no fish