[Formulabruce]

I have joked with folks about doing back road cruises at high idle when MPG is discussed, and honestly I have, with Overdrive. That said, the 8.2:1 ( stock Cr for 72) doesn't seem that smooth and seems rich. It does need the richer mixture at idle to run smooth though. ( a 800 cfm 1978 Q jet is on it and works perfect, TY Shaker 455)
Question is , can a holley sniper improve this situation at say 1500 to 1700 RPM ?
I have APT on the carb and its well adjusted, but the 455 likes to run rich with this E-10 fuel.. thoughts> ???

[Scott65]

If I'm understanding correctly, it sounds like you wanna be able to run different afr in different areas of engine operation. And yes the Holley and others like it can easily do that. What can potentially help driveability (and mileage) as much or more, is the ability to run a non linear ignition curve, if using the timing control features.

[JLMounce]

You'll have to dig into the tuning interface directly and adjust the VE table, but yes the sniper should be able to do that. As Scott mentions, you'll want to run timing control for best efficiency and drivability in such a situation.

[Formulajones]

That's the advantage EFI has over a carb, making small adjustments to the fuel curve in particular areas. If you want more fuel for example at 1700 and 60kpa you can change just that cell.

Can do the same thing with timing as mentioned if using timing control.

It's pretty slick if you're really into the details.