Quote:
Originally Posted by Diesel_Dave
That's odd. I've tuned diesels and it's pretty odd for efficiency and PM/HC to both increase (ususally you'll see efficiency & NOx go together). It does happen on occasion, however, if the conditions are just right. Since it's a turbo remember that adding more fuel will alter where you are on the turbo maps. That will change your efficiency as well (maybe good or bad).
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I measured efficiency in amount of fuel consumed per horsepower generated (BSFC really). I usually do this in vehicle simulation mode since you can use an OBD2 scanner to deliver the fuel consumption values on some vehicles. Proper fuel flow meters are expensive and injector pulse is hard to get into the dyno. Emissions results are usually done on a separate 5 gas analyzer that the dyno can't datalog
Adding more fuel should not change the location in the turbo efficiency maps unless there is a corresponding increase in boost pressure or RPM since RPM will increase the number of pounds of air. Increasing the boost will increase the pressure ratio (and subsequently Lb/h of flow). Adding or subtracting fuel will have no impact on this.