Any "backpressure" is a loosing proposition in any engine. Nowhere in any engine building or design criteria will you find a spec for "backpressure." It's flat bad for any power producing engine. Exhaust systems are all a compromise for sound restrictions. The best ones have NO restriction.
Well, if you just keen to power, then it is so, no "backpressure" thing, but there's also fuel economy and efficiency + some ecology (maybe
) left.You see
bentparts, we have here, in Ukraine, no sound restrictions (there are but none cares) and $5.5 for gallon, so I do mind about blowing my money away, they should fairly be burned in cylinders.
I wrote about "backpressure" considering only naturally aspirated gas feeded engines (atmospheric) but in case of turbocharger/supercharger one must have no restrictions in exhaust.
And again, if a car equipped with a catalytic converter then also no "backpressure" needed. Catalytic converter works itself as "backpressure".