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Boost Gauge Reading Wrong?

KnightRiderR33
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BrOwnY GT Collaborator

BrOwnY GT

Posted
Posted (edited)

]mines actually on +5 on idle...(auto) and jumps to 20 when i rev out its a mechanical cobalt series boost/vac gauge i just tap'd it into the line at the front of the manifold like described in a step by step posted on here i know its wrong coz my stock gauge sits in the - and jumps accordingly.. post-84025-0-70170300-1306822304_thumb.jpg

Edited by nismo07
GT32 Community Regular

GT32

Posted
Posted (edited)

any idea's?

Hmm, not sure. I've always tapped boost gauges directly off the plenum itself. Never really tried to tee it off an existing line. It definitely should be reading somewhere in the negatives on idle though.

Edited by GT32
BrOwnY GT Collaborator

BrOwnY GT

Posted
Posted

Hmm, not sure. I've always tapped boost gauges directly off the plenum itself. Never really tried to tee it off an existing line. It definitely should be reading somewhere in the negatives on idle though.

Was thinking maby trying it at the rear where the stock line goes in from the little box right near the brake booster? if i was to pull that off and run the gauge straight in be fine right? doesnt matter if i disconnect the stock gauge at all does it??

GT32 Community Regular

GT32

Posted
Posted

Hmm, you could be right. Possibly a faulty gauge. I used to have an Omori boost gauge on my old 32. The gauge looked ancient! Was a mechanical type and I remember it was always 1-2psi out. When I had the car dynoed a few years ago, their dyno chart always displayed 1-2psi higher than what the boost gauge in the cabin displayed. It was probably due to wear and tear though. Is the gauge you're using brand new or second hand?

BrOwnY GT Collaborator

BrOwnY GT

Posted
Posted

Hmm, you could be right. Possibly a faulty gauge. I used to have an Omori boost gauge on my old 32. The gauge looked ancient! Was a mechanical type and I remember it was always 1-2psi out. When I had the car dynoed a few years ago, their dyno chart always displayed 1-2psi higher than what the boost gauge in the cabin displayed. It was probably due to wear and tear though. Is the gauge you're using brand new or second hand?

Brand new from autobarn was a cobalt autometer so thought it was quality rofl...

GT32 Community Regular

GT32

Posted
Posted

Hmm, could be faulty. Bring it back and exchange it for another one to see if it still does the same thing. I'm not even gonna bother using a conventional boost gauge this time around in my new car. Once my AVC-R goes in then I'll just rely on that from now on to show me how much boost I'm running. :).

GT32 Community Regular

GT32

Posted
Posted

also shouldnt the gauge reset to 0 when the ignition is off? it sits on 15+ ??

Sorry, didn't see this. Yes it should revert back to +-0 when the ignition is off. If it sits on +15 then there definitely is a problem lol.

BrOwnY GT Collaborator

BrOwnY GT

Posted
Posted

definitely was the gauge lol... funny on the phone to them were trying to blame installation but once they actually looked at it they said "yea its stuffed"... lol dont know how it could be my fault when the needle resets to +15psi and wont go below 5+ anyways yea overnight delivery :)

Mayuri Krab Grand Master

Mayuri Krab

Posted
Posted

kool on another note what should the boost be reading on idle?? -7 like the stock gauge?

Different units, the stock gauge reads in mmHg x100 for both positive & negative pressure.

Most aftermarket boost gauge will read in inHg for negative & either PSI or Bar for positive pressure.

15 - 20 inHg is the norm for idling pressure with the car stationary, anything lower than 15 inHg & you may have a leak somewhere.

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