Jetting
#1
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Jetting
I was wondering if it would be a good idea to up my primary jet size by 1 number from 78 to 79 due to the cooler weather in my area now. I am running 78 pri 86 secondary with a 6.5 pri PV. through out the hot summer and now since the air temps are below 65, I was considering a step up in jets. Holley recommends 1 jet size for every 35 degrees increase or de-crease.
Is this correct??
Is this correct??
#2
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Join Date: Jan 2009
Location: Wilson, NY
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If its running fine...then leave it alone. 1 jet size is nothing, and I'll bet you wont see/feel the difference. Truthfuly, its too much work, and new gaskets, for 1 jet size sir.
#8
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Location: Pennsylvania
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Man, tuff crowd. With cold dry weather maybe another 2-3 jets sizes max in the secondary to even. That would be pretty cold weather. So subtract that off the 6-10 you have 3-7. 3-7 sizes rich from perfect won't cause all those problems, not never, period. It will cause sooty transom and much poorer performance on top assuming you were jetted right in the summer. So don't do it. Leave as is or better yet get an a/f meter and know what is what.
#10
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How radical of an engine? I can't imagine needing to change the jets for cooler weather unless it is a setup that is already on the edge where one or two jet sizes might mean meltdown..