How much power can I expect to gain from custom programming?
The answer to this question is complex, as it depends on many factors. We can say, definitively, in our dyno testing, we’ve seen rear wheel horsepower gains (RWHP) of around 15-20HP on LT1 engines, just by changing the programming on engines that had a cold air intake and other bolt-on mods. We see similar power gains on LS1 engines. If the engine is heavily modified, power increases can be much higher. Engines come from the factory capable of making different levels of power due to manufacturing tolerances. But, GM, in an effort to be efficient, designs factory PCM programs using a “one size fits all” approach. They go conservative on timing, and fuel mixtures. As such, most engines do not produce maximum power using a factory program. Custom PCM programming allows the engine to make more power because the timing curves and fuel mixture are “dialed in” better. The engine runs closer to its optimal air/fuel ratio (AFR) at wide open throttle (WOT), and, hence, makes more power. Also wor
