My Findings...

[CleanSierra]

I wonder if a hammered finish paint, one that automatically dimples up, would be enough texture to give the dimple effect? I've used it on my ports, unknowingly haha.

[Krakin]

When I ported my chevy BB stock heads it was the intake runner that you didn't want smooth so to cause better optimization of the fuel. Now on the exhaust side you want it as smooth as possible for getting exhaust gasses out as fast as possible. I also did work to my aluminum heads on my 427 BBC Brodix RR . I cleaned up the intake port, did a little work to the short side radius and blended the bowls a little better. The heads are stock exhaust port location so it was important to get them nice and smooth as they won't flow as well as the intake side. I run my solid flat tappet cam with a tighter exhaust lash to make up for it.

So after all that post would you call the port on the box the exhaust side or intake side in comparison? So what part would you want smooth and what part would you want rough?

I think that the AES paper I referenced a few pages ago mentions this, as it says the intake and exhausts require different methods, and that the best solution was to balance in between the two.

[Krakin]

Also, what exactly is "boundary layer"?

[Triticum Agricolam]

Also, what exactly is "boundary layer"?

When you have a fluid moving over the surface of an object the molecules closest to that object don't move at all. As you get farther away from the object the molecules begin moving faster and faster until at a point far enough away they are moving at the same speed as the rest of the flow. That area between the object and where the fluid is moving at full speed is the boundary layer.

[TRON]

I hope people are reading this and think "Wow, there's so much physics involved in audio" DUH!

"We live in a world of physics, and physics are predictable. So you don't have to set up the whole thing to find out if it works or not, you can do it on a piece of paper and find out if it works or not" - Thomas Mundorf

[Jessica]

I hope people are reading this and think "Wow, there's so much physics involved in audio" DUH!

"We live in a world of physics, and physics are predictable. So you don't have to set up the whole thing to find out if it works or not, you can do it on a piece of paper and find out if it works or not" - Thomas Mundorf

Give us the math for the physics inside a 98 cavalier, or a 86 yukon, or an 87 astro van accounting for human error and we will use all the paper you want. Until then...

[Dwn4BassAlan]

Well not everyone here has years on years experience engine building dealing with air flow. But hey all I do is bend sheetmetal, machine aluminum, and operate a punching machine. Lot of us normal people don't have access to all the tools he does.

What is the point of getting upset?

Not like Alan or I have the meters this man has, however it would be really cool to have an air velocity meter to do some testing and see how close that WinISD can get to predicting the port velocity.

Yeah man I didn't mean it like that. I meant those of us who might be smart enough or capable enough to do it and would probably want to, but don't because of lazy limitations or lack of sufficient equipment.

Agreed with krakin.

[Dwn4BassAlan]

I hope people are reading this and think "Wow, there's so much physics involved in audio" DUH!

"We live in a world of physics, and physics are predictable. So you don't have to set up the whole thing to find out if it works or not, you can do it on a piece of paper and find out if it works or not" - Thomas Mundorf

lol, if only that was true. There are predictable things in physics yes, but because we don't know everything, real world tests are always necessary. On paper, porsche shouldn't perform as well as they do, (at least that's how the story goes all the time) but hey; they're up there.

There's also the matter of formulas that only work in perfect/ideal set-ups and can't account for all other variances that occur.

Take the idea of finding the amount of back EMF a voicecoil should induce in the subwoofer, we have the equation to figure that out, but we also know that because of the way electrons move along the wire they create their own B and E field, which the law cannot always account for, depending on the circumstances. There is maxwells correction for ampere's law to find this in some cases but even then, the argument of the observation frame of reference comes into play too. So, even with the eletromagnetic field tensor application the paper result might not match the experimental result in every case, so for the idea in air flow and sound pressure; we might be wrong, hence this thread to find out.

[MrBigs63']

So tuned for this. I love the physics of box building.

[Krakin]

You can also use formulas to get your close to the minimum amount of port area needed, however when the formula was created, Richard Small stated in his paper it was only useful for +10% of the actual area that was needed.