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Old 11-09-2011, 01:06 PM   #95 (permalink)
cvetter
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Vetter on EFI

Back on Oct 29, I wrote: "My understanding is that EFI is mostly to meet governmental emission requirements. EFI improvements in performance are measurable at high altitudes. EFI improvements may - or may not - be measurable at very low RPM where atomization can be better with EFI. That said, without government interference, carbs are the choice of virtually all racers in virtually all races. They are my choice, too.

Has anybody done a side-by-side conversion test?"

I found such a test at Scoot Magazine. April Whitney , the editor, gave me permission to reproduce this article for you:
"In the second test, the carbureted Vespa LX150is represented by the blue line, the injected Vespa LX 150 in the red. The power lines seem to be identical, just offset. The carbureted bike produces higher peak power at 6.98 hp whereas the fuel-injected model reaches 6.42 hp max. On the surface, the difference seems negligible. Yet, when you consider that the carbureted engine is tunable in a home garage with some simple jetting changes, it is possible to get a little more power out of that bike, which is not the case with the fuel injected engine.
So, what’s the benefit of the fuel injected model? Better emissions, fuel economy (about 10 mpg better) and reliability. If you could walk into a dealership and were offered both of these bikes at full retail, you would be looking at a $300 difference in favor of the carb version. Not much of a difference.
The verdict? Carb model slightly edges out the i.e. on power. Email: april@scootmagazine.com"

The EFI burns less fuel because it generates less power. I also learned that EFI will use crummy American gas and not clog up like carbs.

See the chart:
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