just a thought

Ok this just kinda came to me a couple days ago and it has made me curious. If you wanted to save gas would you be able to adjust the fuel injectors so that they shot less gas then changed the pistons out with higher compression pistons in order to counter the less gas. If you were to do this you would obviously save gas but by upgrading the pistons to keep the compression at the same as before would you be able to retain at least most of your power? Im sure you couldn't but I'm having trouble figuring out why not.

doesn't sound like it would work to me. i think you are thinking of displacement not compression, tipicilly, cars with less displacement pump less air, so, while keeping the air/fuel mixture at 14.7/1, burns less fuel. when increasing compression, the car still pumps the same amount of air, but it also is working harder to compress the air. i have heard of one or two engines designed from the factory like what you are saying, but they had other factors working for them, and were extrimily underpowered. the hybrid honda insight was like this IIRC. also remember with high compression engines you typicily need to use a higher octane fuel.