Hi everyone. I'm new here. I'e been browsing around quite a bit, but I just never posted. Anyway, I'm just trying learn a little bit about tuning and how stuff works. My question is how exactly does raising the comporession ratio increase horsepower? I know that a compression ratio of 10:1 is like compressing 10 units of air into one, but how do you acually increase power by compressing the air more? I've searched and didn't find an answer. Thanks.

 

It gives you higher temperature & pressure in the combustion chamber, pressing on the piston with more force. If you can avoid detonation, that extra pressure more than makes up for the larger amount of work that it takes to compress the mixture before the spark.

If you've had thermodynamics, it gives a larger area inside the cycle on a P/v diagram.

 

Yeah, it pretty much just gives a more efficient explosion.