Originally Posted by abc4yew

Plow, and about 1850 ft lb of torque .

Most twins I have seen have either a waste gate, BOV or just a bypass tube so that excess boost can by pass the top tubo and go straight to the bottom turbo. The advantabe of the tial or similar is that the top turbo will spool very quick and the second it achieves it most efficient zone all excess is routed to the bottom turbo to bump it to its most efficient zone. It is definitely the most efficient and prevents a drive pressure excess. The bypass tube works in the same fashion but it will result in slightly slower spooling. If there is tons of fueling and the bypass tube is spec'd right then it is more efficient as when boost is near the wastegate opening threshold the wg starts to open and this creates a turbulent flow in the bypass tube. Having a fixed by pass tube gives a constant and smooth bypass flow. The truck I was in that used the bypass tube spooled way faster than mine and peaked at 65 psi (WG) in a heartbeat. ks