Vacuum gauge reading

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Vacuum gauge reading

Post by pinzinator » Fri Sep 22, 2017 11:04 am

What would be considered a normal reading on a vacuum gauge when connected to the intake? How steady should the needle be on a good engine?

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Re: Vacuum gauge reading

Post by rmel » Fri Sep 22, 2017 2:48 pm

Assuming your vacuum gauge is calibrated in Inches of Mercury, at idle 800 -- 1,000 RPM should be about -17 to -20 InHG.
MAP readings are going to be strongly dependent upon load and RPM (and leaks).
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