intake port molds

[Paul Workman]

Originally Posted by tpepmeie

Not trying to offend anyone. Yes, I paid for these heads, but I don't think it is fair to show the finer details of a professional's work, developed from his years in the trade. I am sure he would consider that his trade secrets. He earns a living that way, so I was just trying to respect that, that's all.

Todd

Truly fascinating stuff - this porting thing. And, for that reason, like Bob, I feel more than a little frustration with the holding of information. But! As you said, others have paid the dues and are entitled to the data they developed. If you or I wanna experiment w/ our own stuff and publish the results, nobody would say nay to that.

Just what size/shape is best? A wise old sage once said, "Truth is where you find it!" My point is, there is soooo much more to evaluating porting than a "static" flow bench can evaluate. I'm talking about harmonics set up by the opening and closing of the valves; the interruption and reflection of air flow - harmonics in other words - which play an important roll in "internal supercharging". My point is, what looks best on a (static) flow bench is not necessarily what is going to be best in practice. And, for most of us mortal people, the math gets sooo complicated that all we can do is get close, and then experiment and see what trends develop. The proof is in the pudding, in other words, along with what is desired from then end product.

Gotta run. "Mo later!"

P.

[Jagdpanzer]

Todd,
Thanks for sharing with use.
What material did you use and how did you go about making the port molds?

[XfireZ51]

Todd,

Will you be posting air flow numbers when you get them? How will airflow determine or change the cam specs you land(ed) on?

[tpepmeie]

Originally Posted by Jagdpanzer

Todd,
Thanks for sharing with use.
What material did you use and how did you go about making the port molds?

US Composites 74-30 liquid urethane. The stuff is dead easy to use... just make sure you mix it very thoroughly. Otherwise you end up with a port full of gelatinous goop which never hardens. ask me how I know.

[tpepmeie]

Originally Posted by XfireZ51

Todd,

Will you be posting air flow numbers when you get them? How will airflow determine or change the cam specs you land(ed) on?

Don't have them in front of me right now. From memory...>340's CFM @ .500 lift. But, of course like others have said, we don't race flow benches!

[tpepmeie]

Here are some good SpeedTalk threads on the topic, if you are interested...

http://speedtalk.com/forum/viewtopic.php?t=16689

http://speedtalk.com/forum/viewtopic.php?t=17340

http://speedtalk.com/forum/viewtopic.php?t=18803

http://speedtalk.com/forum/viewtopic.php?t=11578

http://speedtalk.com/forum/viewtopic.php?t=12924

http://speedtalk.com/forum/viewtopic.php?t=18730

http://speedtalk.com/forum/viewtopic.php?t=14205

If you are so inclined, search for posts by Darin Morgan, Erland Cox, cboggs, and maxracesoftware (Larry Meaux).

Todd

[XfireZ51]

Originally Posted by tpepmeie

Don't have them in front of me right now. From memory...>340's CFM @ .500 lift. But, of course like others have said, we don't race flow benches!

I was curious about the low lift numbers and the I/E ratio. No question 340cfm at .5" lift is a great number. Is your cam going to be using that high a lift?

[Jagdpanzer]

Originally Posted by tpepmeie

US Composites 74-30 liquid urethane. The stuff is dead easy to use... just make sure you mix it very thoroughly. Otherwise you end up with a port full of gelatinous goop which never hardens. ask me how I know.

Does this stuff set up ridgid or stay flexable?
and how easy are the molds to extract after setting up?

[flyin ryan]

Originally Posted by Jagdpanzer

how easy are the molds to extract after setting up?

Not hard, use a release agent.

[tpepmeie]

Looks like threads from Sunday didn't come over to the new forum.

Anyway, the heads -small ports and all- flat rocked on another bench and repeated the results seen at RFD. Actually a few cfm better. Amazing results considering only .5mm oversize intake valves.

The housings.... well appear to be a dud. Lost a ton of airflow and couldn't repeat the previous numbers for some reason, not even close. More work to do for sure. It would be an absolute shame to cork up these heads with weak injector housings.

stay tuned.