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On my turbo car, everytime I dropped compression the spool got better and it made more power everywhere.
I am in the process of dropping from 8.5 to 7.8.
It seems counterintuitive but on a boosted car the lower the CR the better.



I wonder how much of that perceived better spool was because the engine was already working so much harder just to run that it was already on the threshold of building boost?

Was that on a V8 engine?


I'd like to dig into this further when I have more time but I will add this:
I have had my own dynos for almost 10 years so I test every change I make to my car. The power curve started higher and earlier with nothing more than an comp change, it was 400 rpm earlier and 28 rwhp or so higher , same turbo, same tune, same boost controller.
The car was a rotary, but its still a 4 stroke motor. The comp change makes the total volume of the cylinder or chamber larger.
Dave Vizard wrote a lot about this in his books, and was the deciding factor for me to take the motor apart to go down to 8.5:1 from 9:1. I put his theories to the test and its proven itself. The interesting thing is the 8.5:1 rotors are actually heavier than the the 9:1 rotors, and the engine still made more power with the 8.5's.
When he says on the cover, speed secrets for any engine , he isn't kidding.