Zeroing the Boost Gauge

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SuperSprynt

New member
When I got my gauge it was perfectly on 0lbs, now its almost a full -1, does anybody know IF a gauge can be recalibrated or is this common and crappy all in one?

Autometer btw.
 
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illGT4

New member
I don't think you can zero it.. :(

1 autometer gauge I had never moved from 0
the other 1 was slightly under 0 :(
 
CMS-GT4

CMS-GT4

Active member
Does this guage show negative? Stock engine should be showing around -15hg when at idle. I have never heard of a boost guage that sits on 0 unless it does not show negative.
 
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alltracman78

Active member
CMS-GT4":2j0vsdoy said:
I have never heard of a boost guage that sits on 0 unless it does not show negative.
Click to expand...

I think he means when the engine isn't running.
And engine should be at 18-20 in/hg.
15 in/hg is a little weak.... :|
 
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toayoztan

Moderator
mine sits at -1 in Hg when the car is off too...i don't think it's really important much, as long as it says 18-20 in Hg when idling. And yeah, 15 in Hg would be pretty weak...suggests pretty good vac leak.

Bryan
 
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furpo

New member
wha sort of boost have you been running. i mate of mine has a 4g61 mitsi running up to 26 psi boost and before he got the right gadge it would move around quite a bit.

roger
 
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alltracman78

Active member
Gary":3nac927t said:
Could it be that there is small vacuum left behind the TB when engine is off? :shrug:
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Doesn't matter. The air pressure inside the engine (once it's off) will be the same as outside. Abient pressure should be 0psi.
 
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gearhead313

New member
I had the same problem a while back...


What you do is take the bulb out and inside you can see a curlyQ type spring thing. Jam a small screwdriver in there and lightly start pusing inward or then outward on the spring and watch the needle move. Once u tweek around in there, you'll be able to get it exactly where u want it.
 
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RedCelicaTRD

Moderator
Ambient pressure is not zero. Pressure varries from day to day within a certian range. You elevation will change it the most. however at my elevation i would have ~4 inches of Hg vacuum which is way more then my gauge shows so it is possible the gauge is a piece of shit.
 
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alltracman78

Active member
RedCelicaTRD":wozozw1a said:
Ambient pressure is not zero. Pressure varries from day to day within a certian range. You elevation will change it the most. however at my elevation i would have ~4 inches of Hg vacuum which is way more then my gauge shows so it is possible the gauge is a piece of shit.
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That is correct. I was making a generalized statement.
 
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gearhead313

New member
holy cow people, u are reading too much into this!


True, ambient pressure changes...but you are trying to gauge your boost setting off of zero. If the elevation would change my boost gauge by 4Hg or something, then i would re-adjust it back to zero so i had the most accurate boost reading possible.
 
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alltracman78

Active member
Now that I think about it, when I was going through the mountains to Tn, my boost g read 0. :shrug:

[I stopped so my buddy could raise his convert top]
 
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SuperSprynt

New member
gearhead313":2tuhjrxk said:
I had the same problem a while back...
What you do is take the bulb out and inside you can see a curlyQ type spring thing. Jam a small screwdriver in there and lightly start pusing inward or then outward on the spring and watch the needle move. Once u tweek around in there, you'll be able to get it exactly where u want it.
Click to expand...

Thanks I'm going to take a look at that. I havent gone over 15psi with the gauge but I couldnt see that being an issue, I think its just crappy.
 
___Scott___

___Scott___

Active member
When you are talking about cheap boost/vac meters, elevation doesn't matter because they are referenced to atmospheric pressure where ever you happen to be.

Vacuum and boost are both myths anyway. Think in terms of absolute pressure and life is simpler.
 
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