How does DIC calc. fuel economy #s?

[MarkZ]

My cobalt, after dropping pulley size, adding bigger injectors and a larger LS4 TB is now running like a diesel with great down low and amazing fuel economy. Tuning to date was been relegated to working around the hardcode limit to get my 60#s to work via upscaling voltage vs. flow rates.

I'm wondering if I'm actually getting good mileage or if the numbers are simply skewed due to the workaround. I have hired help from this forum to do some tuning for me so i anticipate a properly scaled tune shortly.

Does (up)scaling affect how the DIC calculates fuel economy, or am I actually getting decent mileage?

[DanGTP]

I do believe re-scaling the injector tables will change what the computer calculates as your fuel economy. My advice would be to do the math by hand and see how it compares to what the DIC shows. More than likely, though, you're not getting as good of fuel mileage as it shows.

[g5 gxp]

i beleive the DIC is based on factory settins of inj pulse + flow rate + a few other things. once you change injectors, because the pulse widths are shorter down low to accomodate the larger injectors, the DIC computer thinks you are getting better fuel effieciency. i had this issue myself. i was however not getting better mpg. fill tank, reset trip meter and when you run out of gas calculate it the old fashioned way and you'll see how far off it really is

[MarkZ]

Thanks guys, took a tank to figure out that it is quite optimistic. That said, I did a long 1000 mile trip and even highly modded with a canned tune managed comparable #s to bone stock.