the reason turbo chargers work is by using the expansion of the hot exhaust gas to power the compression on the intake charge. if you reduce the amount of fuel/heat going into the engine you will limit the amount of expansion able to turn the turbocharger.
beyond that, you will be running lean, how lean i don't know but that also cools the combustion.
its a nice "outside the box" idea, but im quite confident it won't do anything beneficial.
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