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While I'm thinking about it, EGR serves a fuel economy function: it reduces pumping losses by partially filling the cylinders with effectively inert gases. On Honda's high performance engines that do not have an external EGR valve, Honda advances the intake cam phasing at part throttle specifically to pull exhaust gases into the intake manifold, to be sucked back into the engine (EGR). This does nothing for blowby-related emissions and is there only for the purpose of improving part throttle fuel economy. Racing engines basically never run at part throttle, and when they do, fuel economy is incidental.
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