Here's my last test of the day and my last test until we get more direction from PBR. I went ahead and worked the short side blend a little more as can be seen in the pictures below. This was done with a 1" diameter 60 grit roll and took 1-2 minutes. I basically removed the 70 degree purple line area and blended smoothly back to the SSR. This is still very easy work to do, requires little skill and is not getting near the valve seat itself. This increased the throat to 1.826 wide x 1.851 deep which is now 91%. The first two flow test papers show the incremental improvement over the previous test.
Here's an opinion on throat size. I would love to hear other people's opinions. I do not believe that this latest improvement was because the throat size increased. I believe it is because the shape of the short turn got better. The 91% throat was the result of the modifications, not the goal of the modification. It is my opinion that if we could keep this short side shape and reduce the throat size to 88% that flow would improve. The only way to do that is if there was more metal to work with on the long side. We could then extend some angles, blend in a different way and direct the high speed air on the long side in a different manner. This in effect is an offset throat, i.e. the throat is not concentric with the valve, it is shifted toward the short side.
I thought it would be good to show progress so far, so the last two papers compare the very first flow test of the stock port vs the improvements to date.
I'm done for the day. What's next PBR?
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