AngryJ

I understand the manufacturer sends every car out with the exact same tune, while the engine components aren't always the same based on tolerances. But wouldn't that generic tune already be optimized? Why does a different generic tune from aftermarket companies improve power and torque, while claiming they also improve gas mileage? What specific settings are they altering and what are the potential drawbacks (heat, reliability, emissions, etc)?

TIA

Mike@DiabloSport

GM provides a calibration that, for a lack of better words, is designed around the complete idiot.
They make sure the car will be able to run all day in 1st gear bouncing off the rev limiter, with a tank full of 87, in 110* heat, uphill for 50 miles, because they dont want to have to fix it after it happens.

If you optimize a tune, around an enthusiast or even someone who knows what they are after, and you optimize that calibration for use with premium fuel, and clean up the super safe factory AFRs, you can often find some really good, safe power.
The other side of it is reducing/optimizing torque management, which tends to be rather overly aggressive in many OEM applications, and that can provide quite an improvement in driveability over the stock cal.

There is more to it for sure, but those are my quick thoughts on the subject.

AngryJ

Thanks for the explanation. The above quoted part makes perfect sense to me. I design Dishwashers for GE and they are put through the tortue test and manufactured to withstand conditions WELL outside what they see in the field 99.99% of the time - often at the sacrifice of price and performance.

What parameters are being modified to improve the stock tune (not including the torque management for autos), and how can they be further optimized for each individual engine? I took an internal combustion engine design class in college, but still feel completely ignorant about this stuff. I understand ignition timing and AFR, but that's about it. Curiosity has gotten the best of me. Thanks again.

Mike@DiabloSport

Most of the power gains come from timing and fuel adjustments, but there are also lots of torque limits on the C7, throttle opening rates, shift speed and firmness, tons of stuff that can contribute to an overall better experience behind the wheel.