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Thread: Boost Gauge vs Boost PSIG

  1. #1

    Default Boost Gauge vs Boost PSIG

    Having a problem reading max boost which seems to be low by about 10 psi. I'm suspecting something with MAP sensor, as idle is producing -10 inHg on in car boost/vacuum gauge, while Holley datalog is saying -5 (boost psig) with a MAP of 65 kPa.

  2. #2
    Join Date
    Dec 2009


    Just for reference: (MAP kPa to Boost PSI Equivalents & Boost Control Information)
    May God's grace bless you in the Lord Jesus Christ.
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  3. #3


    Well thank you for the rapid response, but I don't see how this answers my question of why idling, my boost psig is 5 and my vacuum gauge in the car say 10 inHg. I pointed this out as a possible reason the boost side is lower than I expected. For simplicity sake, I just want a datalog parameter that will equal my boost gauge in the car.

  4. #4


    In Danny's LINK, 65 kPa = -10.36 inHg = -5.07 psig. Seems like everything is correct to me. Greg

  5. #5


    Thanks for the response!

    If I could re-cap the problem that got me here in the first place. If I have a Boost psig of 5.5 kPa with a MAP of 140 and a barometric of 101, the tables I've seen say this is just about 5 lbs of boost. Just would like to have somebody say this is correct, before I rip into the new intercooler I just installed.

  6. #6


    Sounds like you're on the right track there.

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