Does a turbocharger add a significant restriction in the exhaust path?
In Hugh MacInnes book, he states : “Many people think this exhaust-gas energy is not free because the turbine wheel causes back pressure on the engine exhaust system. This is true to a certain extent, but when the exhaust valve first opens, the flow through it is critical. Critical flow occurs when the cylinder pressure is more than twice the exhaust manifold pressure. As long as this condition exists, back pressure will not affect flow.
