Originally Posted by
Shadow
Way back in 02? We started what we called the Fully ported 2 piece. At that time, and because comments were made about gasket matching the 2 halves of the manifold being a serious problem, people do what the generally do. They threw the baby out with the bath water and decided it was VooDoo to port anything but the lower lower 1/2 of the manifold.
We had gone away from the 1 piece design for performance almost immediately after beginning wrenching on this platform, just like the G heads, Flow was everything, the rest of the debate fell off me like rain.
Looking for a high RPM high flowing piece, and being Novice porters, I wanted a guarantee that I Knew it was right and no guess work. So I came up with what someone on the forums coined the "Go, No Go" solution. I went to craft shops and measured and bought every size of ball, whether foam, wood ect so that while I was porting I could "drop the ball" through the ported passage and Know that it was Full flow all the way through.
In the beginning this was used mainly for the 52mm TB throat, and it was an eye opener when I would try to pass that ball through a mani we had previously done and Thought was good. The amount of extra material that had to be removed and Where, to allow the ball to pass through was enlightening.
So for the Fully ported version, we started with the closest matched ball size to the gasket that mates the 2 halves. I want to say the ball was 1mm smaller diam IMS. As it passed through the gasket with ease and was not a Tight fit.
We then started the task of opening up the upper 1/2 runners till that ball could roll right into the plenum. Damn, that was a Ton of Al we took out of that piece! Did the neck the same way, port till the 52mm ball rolled through and then finish from there.
Then it was simply a matter of Funneling the lower, starting with the ball size on top and funneling down the lower 1/2 runner to the head flange.
The first car we used that manifold on Exceeded all expectations and quickly moved us far enough ahead of anything else around us that I began to make up my Own mind on things and disregard the "masses" on the net, becoming the Naysayer Slayer! lmao!!!!!
Funny, I didn't Feel like I was Slaying anyone, but since the masses decided to take it upon themselves to deem porting the 2 piece VooDoo, Not understanding what was meant when (Gary D. I believe) said Not to port match the 2 halves to the gasket size, because you will obviously create a "bulb" in the center of the runners, it was thrust upon me, that we "Diss proved that Myth".
I've never attempted to go 58mm TB on a 2 piece because it looked to me that the 52 done Properly was about all the room that was there without welding.
I would check that mani before using a 58mm TB to see if it is actually ported well enough to Flow what a 58mm TB can ;)