Well I just recently finished the third version of my turbo calculator, so these are no longer updated or supported. Th Version 2 is very different from Version 1. I used the equation set from Garrett’s Turbo Tech Articles linked below. This method starts out by inputing a specific horsepower requirement. In addition, this helps to show a boost ramp up effect which is still kind of beta. The method for determining the boost ramp up is described in the spreadsheet. It is depended on many factors as you will soon see. I am always open to new suggestions and other compressor maps you may find. Just e-mail me using the ‘Contact Us’ below.. In addition, this spreadsheet is free and please distribute it. On another note, the V1 Turbo Calculator contains the equation set/method that is similar to the method seen in SCC’s Articles. Compressor Maps – Garrett, Mitsubishi, IHI, KKK, and Holset. I hope to have some more soon.