Originally Posted by AXiS
What is it with you people wanting T3/T4 setups to run 7 PSI on a 1.8 motor?
The simple answer: that's what comes in the more common turbo kits out there.
However there is a bit more of a logical reason. If you plug in some numbers into a turbo calculator, an LS motor running 7 psi of boost (i.e. pressure ratio of 1.5) at redline will flow about 21 air-lbs per min. Take a gander at this compressor map if you will, and see where those numbers put you.
Indeed, it will put you smack dab in the middle, which if you squint is 78% compressor efficiency. That's a mighty fine number to be at.