On a cylinder head,, what would be ideal
volume - shape of the intake tract,
assume that a 90 degree dogleg is not needed, the
direction can be mostly straight up, and that other
CH components are not an issue.
Goal: max air retained in the cylinder.
Note that 'goal' is not:
maximum comparative flow at steady state.
.
some vendors offer differentiated-by-volume models such as:
180cc
195cc
210cc
yet these vendors say nothing about
main section cross-sectional-area
venturi cross-sectional-area
or any mention of Mach number
.
I also find it curious that some intake manifold vendors
offer products with outlets other-than-standard CH inlet size.

 

You're asking for the crown jewels. That kinda info is usually considered top secret, especially amongst the real cylinder head pros.

Not being a pro myself I'd be happy to share my opinion, but it's probably about worthless once you get to the level of questions you are asking.

You might want to ask around on Camaroz28.com in the Advanced Tech section about this. There are some very talented and experienced cylinder head guys who frequent that board.

 

deleted

 

Save your pic to a directory on your CPU, then when you post a reply, at the bottom of the reply box you'll see "browse".

Click browse and search your HD for the pic you saved, then submit the reply.

see example I have from a Vader attachment.

 

OK, now I can't resist. I'll start this off even though I said I wouldn't.

Ideal port cross-section shape: perfectly round.

Why are most stock ports rectangular? Becuase that's how you get maxiumum cross-sectional area when the intake ports are "sandwitched" between 2 vertical pushrods on either side.

 

If you want to learn about "ideal" cylinder head and port configurations, you need to tear apart a late model Japanese sportbike. They are getting 180+ HP out of pump gas powered mass produced engines of only 60 cubic inches, passing smog laws through catylitic converters, passing sound requirements and getting 35mpg with a warranty. And the entire engine/transmission weighs about 150lbs togther.

If your Chevy 350 had that kind of efficiency, it would be putting out over 1000 HP!! (I realize efficiency suffers with bigger engines). However, you will also notice that these heads are all 4 valve per cylinder, and you can open the throttle bodies and look down with a flashlight into the ports, past an open intake valve and see the top of the piston!Can you imagine looking through your TPI throttle body and seeing the piston? Every twist and turn is wasted energy.

Most valuable to us would be the relative valve area Vs the swept area of the engine is huge, but by using 4 valves instead of 2, port velocity remains decent and the valves are not shrouded by the sides of the cylinders. Very short strokes, High RPMs. The port shapes are dimensional to the valve sizes, and the valve seats are used as a venturi, as they are the smallest area in the port. The ports increase gradually in size toward the throttle bodys, a few inches down from which they split (on throttle body per cylinder, but splits into two ports for 2 intake valves per cylinder).

...sorry, no pushrods, rocker arms, cast iron anything. Cylinder bores are plating on aluminum. Super slipper skirt pistons, all forgings. Very impressive for something some pimple faced hat backwards geek is just gonna plow into the back of a Volvo anyway

This probably doesn't answer your question, but I have learned a lot of things from observing those who are successful. The first of which is to copy other successful people and ideas, and try and improve on them.

Troy
So Cal

 

The problem you can't ever get the ideal shapes to work on an engine. There are always different constraints depending upon engine design (sbc,fsb, 4-valve...)

 

deleted

 

Just post it, if its too big just edit your post and add another pic.

 

Actually, I misread the original question.
The diagrams I have are for porting bowtie heads.
I'll post them on another thread soon though.

 

>Ideal port cross-section shape: perfectly round.<
.
I'll restate the premise, and question.
Consider a single, vertical cyclinder.
The intake tract goes essentially straight up.
The best cross-section horizontal, is round.
.
What is the most desireable shape for the vertical criss-section?
It would resemble a carburetor venturi, to some extent, I guess.
Would there be any reason for making the diameter any less
than-->the maximum, which is the 'inner' diameter of the
valve face.?
.
It would nice to know the answer to the ideal case,
befire 'bending' the tube to accomodate various constraints.
.
[thanks for all your responses]