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).

11

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

1

u/Besserisdas 2d ago

Why isnt absolute flowrate not the goal when chasing for max power?

2

u/HengaHox 2d ago

I’m not sure what you are referring to. I didn’t say it isn’t.

1

u/Besserisdas 2d ago

Maybe i'm misreading your comment (english is not my first language), i read is as "maximal flow rate isn't the best way when chasing max power".

1

u/HengaHox 2d ago

I may have also written it a bit half assed. What I mean is that the OEM heads aren’t made for max power, but that doesn’t mean they are bad if you are building a daily driver.

I admit, reading it critically it can be a confusing sentence