Does the ECU have a wide band to judge that? If it's relying on a standard 4-wire narrow band sensor, it won't be able to tell the difference between 14.8 and 15.5.
I do not have a wideband 02 sensor, the stock narrowband 02 is fairly accurate but only when around 14-16:1 beyond that it can really only tell if it's rich or lean.
14.7and 15.5 are the AFR targets for CL fueling that I've programed in the ECU, while I don't have a way to accurately monitor AFR without a wideband the ECU will do everything it can to help the engine maintain this range when in closed loop fueling.
Possibly. More likely it's the reduced drivetrain losses... Drag from all the extra hardware needed for an AWD system can put a noteworthy dent in fuel economy.
If you really want to compare the two, it's worth noting that the most expensive WRX starts at roughly 10 grand cheaper than the least expensive 'vette. 10 grand will buy a lot of gas, and a hatchback with all wheel drive will prove far more practical for day-to-day tasks and dealing with inclement weather than a rear wheel drive sports car.
No its not a Vette, but my G/F's 3.8l Monte Carlo gets high 20's all the time. she was getting better than my accord. The thing turns like 2000 rpm at 65 mph. My civic does 3200! Big slow moving pistons aren't all bad at FE. Im tellin ya if GM can tweak on their push-rod motor cars, I bet they could build a 30+ mpg full sized car with existing parts. Just maybe they could pull themselves out of this.
So the map seems to be a total fail. Last tank driven off under normal driving conditions was 19.5mpg basically what I'd normally see. Plus my IAM is at 15 and won't get up to 16. Time to rethink this, until then I'm going back to my regular stage 2 tune.