Well, theoretically the twin scroll should flow better at high rpm too, as the exhaust gas flows more smoothly through the turbine. I have never seen anything which would suggest otherwise, but I don't think there are many big hp twin scroll cars going around, except maybe for a few evos, and that 6 cylinder GC8 in the states. I made more power with less boost when I went twin scroll, although I did a few other breathing mods at the same time.

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