whats wrong with an engine that was always running boost? I'm sure they can build them tough enough and add better cooling systems. Maybe it's a dumb question, I'm just curious.
closed as unclear what you're asking by Chenmunka, CharlieRB, vini_i, Rory Alsop, Old_Fossil Feb 13 '17 at 16:45
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Nothing is wrong with an engine that is always running boost, but if you don't need 100% power all the time then boost can, and should, be reduced. Most systems allow for variable boost to match engine load and the electronic controls allow more precise matching to improve fuel consumption and also emissions.
Two very obvious issues:
It uses more fuel (as you increase fuel into the cylinder along with air) so that can be an issue.
The system has to be designed to cope with the increased pressure (and temperature) or else it will have a dramatically shortened lifespan.