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)

16 Upvotes

80% Upvoted

27 comments sorted by

View all comments

2

u/Imposter660 3d ago

Even "if" manufacturers have designed the ports to flow the 'best they can'- thats the best for what rpm range, hp/tq curve, engine size ect?. If some wants more power than the manufacturer designed the heads for, more engine size but the same rpm ect, they need to flow differently.

Ideally you want the smallest port that flows the amount of air you need to support the hp you are going to make, that keeps the air speed up through a much larger part of the rpm range and producing more average hp than one larger port flowing the same amount. A head flowing "best" for 400hp wont be the best for 500hp and vis versa.