Chris-PA
Where the Wild Things Are
We're south of AllentownWhere in Pa are you?
Thanks for the link, I had not seen that. Note that the factory blowdown is at 15, which is what I was aiming to preserve but I ended up at 14. I can always raise the exhaust 4 more degree. Also the muffler flows pretty well so that should help to mitigate the issue by allowing cylinder pressure to fall off faster.With too short of a blowdown you will have exhaust pressure in your transfers. Have you done the maps? Here is an older thread that may help you find the best numbers.
http://www.arboristsite.com/community/threads/port-timing-calculator-guide.85786/
I think the other reason for a larger angle between exhaust opening and transfer opening is to reduce the amount of time both ports are open and thereby reduce scavenging losses, but I could be wrong about that. The strato transfers will have only air in them until quite late in the cycle so that is not an issue.
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