dan0617 wrote:
The AFR street port heads are CNC'd also. I wonder if the CNC'd Track 1's are similar to the comp ports or the street ports? $2500 is too high (for me anyway) but I'll bet they will come down some over time. At least I hope they do, I love to see affordable options for those of us on a fairly tight budget.

CentralCoaster wrote:
Does this mean you'll stop posting about it then?

88BlackZ51 wrote:
I certainly hope so Kevin.

CentralCoaster wrote:
Does this mean you'll stop posting about it then?

pr0zac wrote:
Quote:

88BlackZ51 wrote:
I certainly hope so Kevin.

is there anyway to turn this guy off. god i love how he can put his unwanted two cents in everywhere without anyone saying anything.

jsup wrote:
Quote:

CentralCoaster wrote:
Does this mean you'll stop posting about it then?

Means when I learn something I'm big enough to post it for everyone's information. What this means is that all heads are even more equal.

Hey CC, did you ask anyone else this question? Just wonderin' if it's a one way street is all.

jsup wrote:

Watch the video. Brodix lightly CNCs their standard heads to gasket match. The Track1s that are fully ported do the bowls, runners, everything, comparable to the Comp Ports, hopefully Tony will clarify that.

The Track1s are Brodix higher end line. They start with the IKs, then go to Race Rites, then to Track 1s. I am not sure which one of those lines the Comp Ports compare to if they were fully ported. Maybe not the IKs, but maybe not the Track1s. I'm thinking a fully ported Race Rite would be the fair comparison.

Qack wrote:
One thought -- IMHO a CNC-machined head is really only as good as a really good artist doing the work manually. There's no magic in CNC and, because of the mathematical curve-fitting functions involved, it is likely may not be as good as a top-notch artist.

CentralCoaster wrote:
What is the consensus on the surface finish of the intake ports?

I understand that castings are naturally going to be vary CCs and flow more between ports, vs CNC work, but...

Does the slick surface become "sticky" at some point? Can't some surface roughness be a good thing for breaking up the boundary layer at the surface?

Does it change for wet flow in the head vs. dry flow in the intake?

What sort of air velocity are we getting in the intake ports?

CentralCoaster wrote:
What is the consensus on the surface finish of the intake ports?

I understand that castings are naturally going to be vary CCs and flow more between ports, vs CNC work, but...

Does the slick surface become "sticky" at some point? Can't some surface roughness be a good thing for breaking up the boundary layer at the surface?

Does it change for wet flow in the head vs. dry flow in the intake?

What sort of air velocity are we getting in the intake ports?

jsup wrote:

As far as wet flow vs. dry flow in the intake, the answer is the same as for heads. Most leading manufacturers have evolved past the hack, guess, and flow method as Beach Bum has described. They use a combination of CAD and wet flow to get to a design, then test it in a Spintron rigged with high speed cameras. What BB describes, is an antiquated method by today's standards. This is not one company's propaganda, it's pretty much industry accepted. That's not to say that what BB describes has no value at some point in the process, it's just not how development is done anymore. It's too expensive and time consuming. Better products can be developed faster and more cheaply using modern technology.

jsup wrote:
Quote:

CentralCoaster wrote:
What is the consensus on the surface finish of the intake ports?

I understand that castings are naturally going to be vary CCs and flow more between ports, vs CNC work, but...

Does the slick surface become "sticky" at some point? Can't some surface roughness be a good thing for breaking up the boundary layer at the surface?

Does it change for wet flow in the head vs. dry flow in the intake?

What sort of air velocity are we getting in the intake ports?

My understanding is that it makes no difference. Air rides on a small layer of air (if that makes any sense) and since the air going through the path to the cyl never actually touches the surface of that surface directly, it has zero effect. There's a specific technical engineering term for it which I can not remember right now. Polishing or "rough" finish is all a myth.

As far as wet flow vs. dry flow in the intake, the answer is the same as for heads. Most leading manufacturers have evolved past the hack, guess, and flow method as Beach Bum has described. They use a combination of CAD and wet flow to get to a design, then test it in a Spintron rigged with high speed cameras. What BB describes, is an antiquated method by today's standards. This is not one company's propaganda, it's pretty much industry accepted. That's not to say that what BB describes has no value at some point in the process, it's just not how development is done anymore. It's too expensive and time consuming. Better products can be developed faster and more cheaply using modern technology.

BeachBum wrote:

The hack & guess method ? How do you think a manufacturer got the original CAD file ? Then, after they get the CAD file, they will massage the tool path via a good cad/cam program.... Ie, the cam part being necessary unless you just want a useless cad file. (you could print it, but you can't machine it) Specifically, they are typically rounding the massive series of linear points they have to create a smooth path, this can be done in a variety of ways such as NURBS or simple G-code commands that instruct the CNC to automatically corner round each axes command transition. They can also shift it and massage the path, thus raising or lowering the roof for example or shifting the port enough to allow for a water jacket. But, I think I previously mentioned they massage the port design to get a casting.

Spintron ??? Spintron is most commonly utilized for valvetrain issues.... when did they become involved in "creating" a tool path file for a cylinder head?.... thats new to me. I don't have any clue how that would work, can you elborate on how Spintron (the high speed cameras) would create a tool path ?

btw, with a wetflow tested port, what happens to it after a porter modifies with his own cnc program from a wetflow perspective?

cuisinartvette wrote:
The computer generated design is only as good as the person behind the keyboard. I know of at least one mfr that has that done and their heads are horrible. Perhaps some more talent there could change that.
Youd be surprised who still hand ports and manually changes their ports designs.

jsup wrote:

Sorry, perhaps I wasn't clear. That's why I said that it still has it's place.


I don't really understand how digitizing a port is hard. If you can't probe it, you certainly can't cut it.

If a company that does digitizing does not have the correct probes, they should hire an outside company to do the digitizing or buy the correct probe.

Further, what company is doing 5-axis port machining and does not have the CAD geometry for the casting? If they had the geometry for the casting, they could do the porting in CAD before machining. Am I wrong?

For clarity sake in the old days before CAD availability, the process was to take a head, hand port it, flow the port, see what you get.

The next step was to take the next cyl, port it slightly differently, flow it, see what you get.

Repeat six more times per set of heads. Pick the best one, repeat on a new set of heads.

Sometimes, you hit the mark either by skill or by accident. This was the "old time" process in getting port design. Time consuming and expensive.

Enter CNC, and as you spelled out, you had to re create it in the way you outline.

With current technology that process can be simulated and fed to the CNC machine, hell, I've seen it first hand where a design was fed to a machine that literally spit out a 3 dimensional representation carved from a solid block.

That design will be tested on a wet flow bench to ensure what they got, is what they expected. If it is not, that information fed back into the CAD for modification and further simulation.

As time goes on and more information is gathered, the old grind and guess method will be eliminated completely.

That is the way I understand it.
Quote:

Spintron ??? Spintron is most commonly utilized for valvetrain issues.... when did they become involved in "creating" a tool path file for a cylinder head?.... thats new to me. I don't have any clue how that would work, can you elborate on how Spintron (the high speed cameras) would create a tool path ?

Spintron is a separate issue. Remember what I said, outfitted with high speed cameras.

As a wet flow bench is used to verify design scientifically in a static situation, which is the limitation of wet flow, the Spintron allows engineers to see how this stuff works under operational environments. Cameras are actually put inside cylinders to see what happens in those conditions. It is far far more than just a valve train analyzer. It does NOT create a tool path at all. It is a tool to better understand what happens when a design is implemented in the field under the conditions it will be working. Has nothing to do with tooling.

Quote:

btw, with a wetflow tested port, what happens to it after a porter modifies with his own cnc program from a wetflow perspective?

I guess it depends on the change. The wet flow is to find out what happens after a change, hand or CNC port. That's the piont of wet flow and why it is a significant step up from dry flow. But still, because static, is still not as good as Spintron.

cuisinartvette wrote:
The computer generated design is only as good as the person behind the keyboard. I know of at least one mfr that has that done and their heads are horrible. Perhaps some more talent there could change that.
Youd be surprised who still hand ports and manually changes their ports designs.

Quartz and sapphire ports through piston crowns and cylinder walls enable researchers to analyze combustion events with high powered lasers and precision cameras.