B2 Motorsports - Jeff Lipton 487 FE Build

[blykins]

Port area isnt constant....

But think of it this way: air and fuel has momentum. It takes time to get it moving. Guys that port their stuff at home have a tendency to hog the ports out as big as they can, thinking a big port makes more power. In reality, a smaller port that flows the same as a big port will most likely perform better because the velocity of the charge will be higher and you can shove more in with respect to time.

Perfect scenario is a port that flows a lot, but is efficient enough to have high velocity as well.

[Chilibit]

I was with you right up until the last phrase:

"and you can shove more in with respect to time."

Does this not violate the "flows the same" premise?

I agree with the 'perfect scenario.'

Originally Posted by blykins

Port area isnt constant....

But think of it this way: air and fuel has momentum. It takes time to get it moving. Guys that port their stuff at home have a tendency to hog the ports out as big as they can, thinking a big port makes more power. In reality, a smaller port that flows the same as a big port will most likely perform better because the velocity of the charge will be higher and you can shove more in with respect to time.

Perfect scenario is a port that flows a lot, but is efficient enough to have high velocity as well.

[blykins]

I'm not the best at explaining things...

Let me try it this way...

You can have an excellent flowing head that performs like doo-doo. You can have a poorer flowing head (read lower numbers) with excellent velocity that performs awesomely.

The reason is because the application varies from case to case and since we're speaking of street engines here that require great throttle response and operate at "sane" rpm levels, you want a head that has higher velocity so that it's easier to make an amount of air/fuel move.