What are the differences between an economy tune and a performance tune? Don't they both optimize the engine and transmission to get more output? Wouldn't the two tunes be the same?

The only difference I could think of would be that a performance tune would have higher shift points. Does anyone have more insight into the differences?

 

You pretty much nailed it regarding the part-throttle shifts. The economy tune will also have lower TC lock-up points. WOT shifts can also be different.

In addition to the tuner's (the guy writing the tune) preferences, each truck responds differently to tuning, so there may be other differences (throttle response).

I always recommend you discuss the tunes with your tuner to make sure you're getting exactly what you want.

Maybe Mike Butler will stop by and let us in on some of the details.

 

Depending on vehicle. Perf tune and Economy tunes may differ. The key for economy is to reduce pumping loses in the engine , lock the converter and alter fueling delays. Honestly on some vehicles the factory does a great job (computer nanny) taking economy out of the drivers hands and controls it for you. With that said a perf type tune if driven smart may also net economy and when power is needed just step on it.

 

I understand locking the converter but what are pumping loses and fueling delay?

 

Pumping losses can be thought of like frictional losses that occur as the engine draws air past the [mostly closed] throttle body blade and forcing the exhaust gases past the exhaust valve into the exhaust system. The main way pumping losses are counteracted is by increasing EGR flow into the engine and ever so slightly biasing the O2s to lean out the engine a couple of tenths of an air:fuel ratio. Both of these modifications will require more throttle opening to maintain a given vehicle acceleration or speed, thus reducing the work the engine has to overcome to draw in the required airflow. To reduce losses in the exhaust side of things, tuned headers (such as longtubes) create low pressure waves (rarefactions) that travel back up neighboring exhaust primaries; these low-pressure pockets of air draw the exhaust gases out of the cylinder past the exhaust valve thus alleviating the engine of doing this work from the sole motion of the crankshaft pushing the piston up the cylinder.

I'm not familiar with the term "fueling delays", but I think it may have to do with fueling logic that the pcm uses to anticipate instantaneous fuel requirements due to sudden, abrupt throttle changes where the maf meter may lag due to its location in the intake tract. This is one area where you don't want the pcm to "over shoot" the fueling needs since it would just be wasted fuel.