On static flash "chips" such as a normal cars stock computer or most aftermarket standard EFI computers such as Diablo Sport or Summit, only one tune can be flashed on the "chip". This is the most common setup that we're used to. In these cars, like you guys are discussing, when there's an atmospheric pressure change such as altitude or air temp (cooler air is denser), the computer advances or retards the timing. The QuarterHorse computer the chip is not only re-flashable on the fly, but it can hold several different engine tunes. This requires a setup that can handle variation, i.e. larger fuel rails, larger injectors, higher flow fuel pump, etc. So basically, if you run at maximum horse power at 5,000 ft then at 9,000 ft you cannot get the power back. However, as with the great majority of cars, you intentionally program a less powerful tune than what is actually possible, adding drivability, fuel economy, less wear and tear on engine components. Remember here the point of the EFI is to have drivability and performance optimized, not balls-out performance 100% of the time, although you can do that too. So anyway, if we're choosing an engine tune that's in the performance middle ground the engine will live happy and will run better overall. So say the middle road tune makes 400hp but the max is 500hp. We head to the mountains and lose 20% of our hp. If we run the middle road tune we're down to 320hp, but if we switch to the max tune we're right back to 400hp, but we cannot go anymore as that is the new max. Forced induction adds a little variability in the possible tunes too. Like I said, if you run a max hp tune all the time then no, any power you lose at altitude cannot be regained through an engine tune.
. I love my EFI and would never go back to carbs.
