Yesterday i took my 1999 E55 AMG from garage and the car was ready with kleemann kompressor and i tested it for the first time the car sames it didn't get any horsepower.

Then i return it back to the garage and they told me that they fixed the wrong pully and it was only 0.25 bar opend.they will change the pully to a smaller one to increase the bar to 0.45bar.

My question is: Is the pully size control the kompressor boost????? please help