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Old 02-11-2014, 06:12 PM
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cbmontgo cbmontgo is offline
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Join Date: Dec 2007
Location: Texas
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Originally Posted by kurtnkegger View Post
I got this information by googling engine vacuum at elevation...I've understood there would be a 1" drop for every 1000ft of elevation.

When testing manifold vacuum, it’s important to remember that if an engine idles at 22” Hg at sea level, it will idle at about 17” Hg at 5,000’, 14” Hg at 8,000’ and 12” Hg at 10,000’ altitude. Variations from the calculated standard, of course, are the weather conditions, the engine design, and how well the engine management system adjusts spark advance and air/fuel mixture to correspond to a change in barometric pressure.
Yep. That's why it seems that 14" isn't too bad at 7,000'. I just don't want to start replacing manifold gaskets if I don't need to.
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