Does anyone know with certainty what the values in the map field represent when they indicate a + value or a - value. I'm guessing a negative is a leaner condition and positive is a richer condition but I'd only be guessing. And what does each value represent, ie. -20 is a value but in what units etc. Anyone know for certain? I always heard the stock map is on the lean side for emissions so if this is so and with the addition of an aftermarket pipe(should run leaner due to easier air flow) then why do most maps I see run a lot of negative values in the lower to mid column and row values? It just doesn't seem intuitive.