True throat/window, low port heads

[blaktopr]

ssr

[blaktopr]

floor

[blaktopr]

roof

[maxracesoftware]

What are the Intake and Exhaust Valve diameters ? ?

What FlowBench Bore diameter Fixture

[blaktopr]

2.03/1.77, I am still thinking bout the valve size on the intake. 4.185 bore. I was tossing and turning last night knowing how thin the metal is in some places.

[blaktopr]

I am using this head to get refamiliar with techniques and to see how the car will perform by putting the choke closest to the valve with the highest speeds at the valve. That topic has been discussed to death. I want to see for myself and in my own car and get some results to add to my knowledge. Port is still about 175cc and the throat or smallest part of the port in this head (in my understanding) happens about .500 to .750 before the seat. The 2.03 is a byproduct of the steeper seat angle for testing and getting the speeds up through there. Jamming in a bigger valve without opening deeper into the bowl and effecting the throat size makes no DRASTIC change. I will be happy enough if I can get enough passes to get info to use for the future. The next step is a set of E-Heads that I will be R&Ding for my friend and I. His head was ported by another builder and has a 2.19 with the push area the same as mine on the iron heads. They flow 315 and once I get the fresh bare head, I will start to map that port and get some figures. The R&D head will eventually be used in my motor. Since he is running an 8000 rpm 400 and me a 462 at a lower rpm, I will have to keep tabs on the shapes so I can get a profile that will suit him and still have this head suit mine.
Chris

[blaktopr]

The pics give me a better look at the port. It seems the ssr can be widened based on the width at the wall, but I think the area of water follows the radius of the sides. I see the pitot tube readings also showing the unequalness at the ssr floor apex. I would like to see that corrected. But thickness, and the fear to alter the flow curve is why I didn't try it yet.

[blaktopr]

Now, I am getting a little flustered. Gotta take a step back and ask for some input. I re measured the throat area and is a little bigger, now the proper valve job is in there. But you can reference it from a few spots and the number can change. But with the area throat that I came up with, I came up that the 2.12 valve is the size needed for the 90% rule. This is where the frustration comes in. The port is cleaned up. I ever so slightly dug out the ssr apex width to try to slow the speeds over the ssr. I tried the 2.12 valve with a 45 seat. The port still goes turbulent at .550 AND keeps picking up flow through the whole flow curve, messing with the velocities. Speeds are up at the pinch. They are all over in the seat area but still has some good areas of speed faster than the pinch and some slower. I am trying to retain a good port profile but these very small changes are giving me gains that mess with other variables. What do you guys think? Here are the most recient results. The 2.12 valve is still slightly sunk but I did not alter the throat for the valve. The 45 seat angle still accept the bigger valve, the 55 seat accepts the smaller.
.200 142
.300 198
.400 244
.475 267
.500 273
.525 278
.550 267
.575 267
.600 267

[blaktopr]

bowl

[blaktopr]

ssr

[blaktopr]

Well today I learned how to kill a port with the wrong valve seat cuts/angles. :angry: Gonna use what I learned and start the next port. I'll come back later to try to fix the seat. Live and learn.

[200cfm]

Did you loose the 267 cfm at .550"? Is your cam lift going above that? Once the intake is installed it may not go turbulent above that lift. How soon can you track test it for a baseline. Might be in the zone already.

[blaktopr]

200, it was in the 270's. The cam that was going to be used was a solid flat tappet with .550 lift after lash. The port tanked, went turbulent at like .450 and flow dropped 25 cfm at .475 and up. There was a part of the seat that had thin width cuts and transitioned very quickly. The wall was straight and then the seat turn happened fast. This was on the side of the exhaust valve, and the air was detaching in that area in the seat. About one inch to inch and a half long around the seat. So I tried to see if wider seat cuts and less of them (4) would give the air more opportunity to hold through that area. The bottom cut was blended into the port as was the top. I think it aggravated the ssr transition. I am just going to go back to it later without being mad at it to try to save the port. I GOT TOO GREEDY. I should have stayed with the seat cuts I had to also be able to test the difference between a small valve and larger. I will stick with what I learned with the remaining 7. At least it is still something learned. It will be sometime in the spring/summer when I get to test this thing. I have the rest of the intakes and then R&D the exhaust. The motor needs some machining and parts before assembly. Plus, soon I will be doing the R&D thing on some AL heads for a friend who wants to get the motor on the dyno this spring. He has been working hard on loosing weight and setting up a good suspention system in the car. First it was 650 to 700HP he wanted. Then the possibility of a solid 700 with the parts he has was getting tossed around. Now he has a new found confidence in what I knew, know, learned and testing with and wants to get another head for me to get the most efficient air out of it to try to get 700+ HP. Then there is this. To help a board member on a different board who runs a turbo. He is a moderator and has helped many DIY'es with easy turbo setups for Pontiacs. He went lean and did some damage. I asked him if I can be a part of his future project keeping it low buck as before. I offered to port his iron heads for free. He was running 9.70's. He mentioned he would like to get into the 8's if possible. I've allways been more of a crew chief type than a racer/owner. Maybe thats because I get to be involved in many different types of combos with out owning all of them. But I get great satisfaction when they run good numbers. Hopefully, I can get to finishing mine also.
Chris.