I'm in the hunt for some slightly better fuel economy out of my 5.7 w/6-speed trans. I know from previous tuning experience (2 1/2 decades ago) that adding a few degrees, in the cells where the car cruises at, will help.
My question is does the Dodge mapping use PT Base for its spark advance under light-load applications, or does it use MBT Base in those instances? Or is it a combination of maps?
I added a degree or two in PT Base where the cruise control is set to 65MPH on flat road. (Aircharge - .25g, RPM - 1504, MAP ~50kpa, Advance - 23.5?).
After adding those couple of degrees in PT Base map, there was only a tenth or two of actual timing change on my next test drive. So that got me thinking and looking for another table. That's when I found the MBT Base map, and the advance value is 24? in that particular cell. In the PT Base map, I had raised it to 25.5?. The MBT Base map value seemed more accurate of what I was logging.
So, I figured I'd seek some insight from the forums.
TIA,
Ron