by KTA » Mon Feb 04, 2008 8:22 pm
Turbos work off of pressure ratio, typically most turbos are effecient at a PR of 3 to 4. ATmospheric pressure is 14.7 so at a PR of 4x 14.7psi- 14.7 = 44psi gage
so now say you have 45psi feeding your manifold charger still operating at a PR of 4 X 45 - 45= 135PSI. In actual practice your PR would not remain at 4 for your manifold because of backpressure across the turbine reducing work input to the compressor, so you typically end up more like 2.5x45-45= 67.5psi in order to keep your drive pressure in check, this of course varies deending on many things in your setup.
Fleet of Junk: 1989 D350 627rwhp 1300 tq B-1/Hx60 twins, KTA pump/injectors, ported head, BIG fuel supply. 13.75@ 109.5mph 1/4: 1992 W350 Cab-chasis, 1993 W350 ext cab cust.370 inj Hx40/16cm 290rwhp hydroboost brakes,1984 D350 crew-cab another project.