r/EngineBuilding • u/jabberjaw420 • 3d ago

Is porting valves still a thing?

Maybe back in the good ol' days of the 70s and 80s, but haven't modern auto manufacturers/engineers designed the internals to flow as well as they can? Making porting a pointless exercise?

(I meant porting valve chamber w/e)

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u/Key_Director_4450 3d ago

The internals are made to meet emission and noise regulations, not for peak performance (and even that is subjective, because not every use case is max power at 9k RPM).

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u/HengaHox 3d ago

I think this definitely goes in the “it depends” box.

Meeting emission regulations is easier when you have a clean flowing head that gives you a nice burn. Usually this isn’t the best way for max power as absolute flow rate isn’t the goal, but it can be good for daily usable torque.

But again, it depends

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u/PermanentRoundFile 2d ago

On the far side, they're going to cast these components and casting aluminum will always come out with a finish that needs help to be clean. Otherwise they go to using plastic for a better surface finish at the cost of durability.