[Christ]

There were a few posts about that exact thing somewhere.. I was asking about the Pagani Zonda b/c of its' exhaust routing choice. (Centered exhaust ducts)

The problem with using a turbo in that way is that unless the hot side was "geared" a whole bunch lower than the cold side (think: T3/T4 hybrid, x10) you'd never get that kind of boost w/o being at full throttle.

Turbochargers rely on a feedback loop to spool, hence part of the reason for "turbo lag". Again, you're not going to make free power, and a turbo is no exception. The more work the turbo is doing, the more restrictive it becomes to the exhaust (work load). This adds back pressure, and removes efficiency.

You'd be better off applying that energy to keeping the turbo in a negative pressure range, or "0" boost. That way, any backpressure applied to the exhaust would be nullified by the extra power made from the feedback loop to the turbo, and you'd gain efficiency in the form of less pumping losses.

One exception to this would be to mount a very small hot-side in the intake charge, so that as the engine revved higher, it would spool the turbo, and cause an induction resistance that could still be resolved with the "power-adder turbo", then venting the second turbo's boost side to the atmosphere behind the car.

I'm not sure exactly how well this would work, but I'm sure someone will come up with some math to show that it's not worth the time or effort.