I can run a carb leaner at cruise than EFI correct?

[Shawn MacAnanny]

Just working out the finishing touches on tuning and i'm looking to run abotu 40 degrees of timing at max vacuum advace while cruising and i wanted to lean out the cruise to about 15:1 or so. I have heard of people going as lean at 16:1 because the fuel is cooler coming from a carburetor or something. My intake is a shotgun dual scoop protruding through the hood so it wont be drawing in warm air.

[6'9"Witha69]

That is the conventional wisdom. And while you can get there with tons of trial and error, an EFI setup will be easier to tune to it's best and will stay there better overall through a longer band of RPMs and speeds. Of course this is where factory systems work better than even basic speed density systems.

[Shawn MacAnanny]

well i have a fast dual wideband, and just ordered a set of holley fully adjustable metering blocks and i have a 50cc accelerator pump so my goal is to make as much HP and MPG as i can. I really think I'll make a few more HP with the carb set being im running a scoop to pull in cool air straight into my carb. I'll keep testing and tuning on the road. With the holley adustble metering plates i can tune the primary and secondary jets just like the idle mixture.

[68Formula]

Actually you can run EFI that lean as well especially since you don't have to worry about puddling of the fuel (assuming correct injector targeting). The main reason the factory EFI setups run stoich is because that is the optimum ratio for the catalyst to properly function. Aftermarket systems generally followed suit (especially since it allows them to use a narrow-band O2).

So with EFI, if no catalyst but using a wide-band O2, ratios higher than 15:1 are possible.