Why is this it don't make sense please some one its driving me crazy

 

Short answer is temperature. Actually it's larger turbo make more power at the same boost most of the time. So as a compressor runs it creates heat as it compresses air all of them do it. Smaller compressor is doing more work to get the same pressure. Thus making more heat .heat expands air so it's less density. Acts like less boost .thus dubbed effecenty. When you look at a compressor map the present numbers are effecenty so that's why a turbo that's to big will make less power just like one that's to small. As you get to either end of the map effecenty falls off.

 

So my smaller turbo makes more power

 

Usually means your at a better efficiency island on the compressor map and turbine size and ar is good for your level on your motor. So less heat generated and better VE. So your getting a better power peak lower in the rpm range but you may see some drop off as you push rpm higher. On your bigger turbo if you spin it harder and add some more boost you would likely see a larger jump in power ie 30-40hp per psi. Where as if you work the smaller turbo to the same level you wouldn't see as much gain 15-20hp per psi. There is a sweet spot when it comes to sizing. In general larger wheels will make more peak power at a higher rpm since the motor tends to make more power with rpm already, but it is not always bigger is better, especially when it comes to boost rise and power under the curve.