Contour Enthusiasts Group Archives Forums Modifications 3.0L Duratec Head Theory

Started porting my heads this week to accept SVT manifolds. In the process I'm finally seeing the venturi being formed but still have a few ideas that I want opinions on.

There is a large gap in the center of the head now and wanted to extend the splitter by adding or welding material to turn the head back to a split port style. Now before you go thinking why would you wanna do that, here me out. The opening of where the venturi starts isnt a complete one. Only about 70% of a complete circular opening. By doing this you have material in the head to complete the opening of the venturi. This design I would think also increases the ports velocity by there being a more uniform entry for incoming air and continuing all the way through to the valves.

You would be losing the tumble swirl affect that promotes better fuel atomization though for the secondary runners. But it would be a trade off. So is there any benefit or is there nothing to had.

Hmm. I have no idea. It seems to me that you would want to just get split port heads?
I haven't seen any advantage of a well done ovalport over a well done split port.
And Demon's system has the best track times we can't use his as an example because he has full control over his engine management and hasn't dyno'd for comparison. It's only been in the last 6 months that everyone else can get full engine managment so.... Why would you want to turn an ovalport essentially into a split port?
Or am I interpreting your question/theory wrong?

When you did your heads did you notice how the Split port gasket layed over the 3L port it was wider and taller. My ports the way I shaped the are like a venturi in a carbuerator. When the air comes in it is compressed and then released at a higher speed etc... The open isn't a complete venturi meaning it doesnt "cave in" into a smaller diameter at all angles. Only about 70% of the opening is shaped like that. So when you are basically turning it back into a split port you have the material to shape the remaining 30% in to form a complete venturi. Then by having the smaller uniform passage back to the valves it is essentially increasing the pressure giving better cylinder filling. I'll get some pics up asap to show what I'm trying to say

I'm not following you. I know the split port gasket it bigger than the ovalport opening, significantly. I know that the ovalport can be fully divided if you put in the material to extend the divider.
But you would have to widen out the tops to fit and then you will end up restricting it down quite a bit as it goes into the cylinders. Granted it will improve cylinder filling at low rpm but what about higher rpm? Will it improve anything or restrict flow?

There wouldn't be any restriction. Unless you're taking about further down into the head where I wouldnt be doing any adding. Just picture the splitter coming strait up to the intake port opening. That is the only adding that would be done. I will have to get pictures for you to fully understand.

In theory as the engine speed is increasing, sucking in more air, it will be assisted by the increase in pressure created from the venturi which is what it is intended to do. As for restricting flow, it would be no worse than the already too small stock oval ports.

And what were the mods with 209hp?
Most of the hybrid's have much much more mods than the oval port which put down 209hp... So its basically like comparing apples to apple pie

I'm just gonna see if I can get them flow benched so then we have some numbers to work w/ if I decide to do this.