I'm not convinced about the need for 14 volts, if
folks here are already making more mpg without the alternator, then isn't that the point? Have any of these folks said it was a problem? Most every electrical component I know has some degree of tolerance, and alternator (and belts) do break.
I would definitely test that theory before buying a DC-DC converter, but use fillup to fillup data and not instrumentation. Changing the system voltage WILL affect your injector pulse length, your cars computer should be able to handle it though (that is reflected in the pulse length change).
Plus all your cars lightbulbs will probably last forever
