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Old 11-01-2011, 11:19 AM   #86 (permalink)
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Originally Posted by cvetter View Post
My understanding is that EFI is mostly to meet governmental emission requirements
One of the big advantages of FI is being able to alter the fuel mixture "map". Instead of having a mixture set for idle (pilot jet), midrange (needle jet), and WOT (main jet) like a carb has, a FI system can breakdown the metering into smaller adjustments based on the specific needs of the engine at a certain RPM.

I'm pretty sure an injector will atomize the fuel better as well, and meter small amounts of fuel more accurately. Current automotive FI systems also go into Deceleration Fuel Cut Off (DFCO) mode that stops fuel flow during coasting to increase FE.

Overall it's more flexible, accurate, and efficient.

Chances are if the same engine makes more power or gets better FE with a carb, the FI is not adjusted properly.
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