School me please

[slammedSI]

I want to know exactly how the turbo on the 6.0 motors work, I know its boost is controled my vains but how really is it done?

[720Deere]

Think of the exhaust side of the VGT as a variable pitch fan. When more boost is required, the pitch of the vanes is changed so that the exhaust wheel is pushed harder by the escaping exhaust gas. When little or no boost is required, the vanes close up so the exhaust doesn't push the wheel as hard.

[mschn99]

The vains are the key element. The PCM uses a stratagy to caluclate the backpressure (which equates to potential driver pressure) in the Y pipes (pre turbo. It then adjusts the vains to controll that pressure. The more pressure in the "pre turbo" pipes, the faster the exhast side turbine spins....which means more boost. The vaines open up to lower the backpressure (lower boost) and close down to raise the backpressure (more boost)