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Vacuum gauges

DFECTED

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How do vacuum gauges exactly work and what is there exact purpose?
 

VR38

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A vacuum gauge measures how much vacuum the piston creates on the induction stroke.
A vacuum gauge has two primary functions, 1; Measures the engines efficiency of the motors induction side of the pumping action of the motor (or should we say sucking action) for example, if your valves are not seating the reading on the vacuum gauge will be lower than normal, 2; It ia used as an economy gauge as in the VC commodore where again, when a motor is most fuel efficient is when vacuum is high so you would aim to drive your car with light throttle action to keep the vacuum high which helps the carby etc vaporise the fuel better.

As with both it is a very valuable tuning tool.

Hope that helps.
 

henrytad

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ive got one intsallde with my vz, i originally got it just cause its a good looking gauge but it is like vr38 said very useful, especially if you think theres a leak or your losing suction somewhere
 

SUP3RST4R_DJ

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I was looking at these but a mate of mine thought they were only for turbo cars and on a na car it would just be running in negative, but I think he may have been thinking of a boost gauge,

in a commodore vz v6 does anyone know where to tap the vacuum hose into?

Thanks

EDIT: also is anyone able to put up a video of one in a na vz v6? Just to see one really work. Ta
 

iaydemir

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I was looking at these but a mate of mine thought they were only for turbo cars and on a na car it would just be running in negative, but I think he may have been thinking of a boost gauge,

in a commodore vz v6 does anyone know where to tap the vacuum hose into?

Thanks

EDIT: also is anyone able to put up a video of one in a na vz v6? Just to see one really work. Ta

Tap into vacuum line behind manifold:
http://forums.justcommodores.com.au/vy-holden-commodore-2002-2004/96517-where-vacuum-tube-vz-alloytec-motor.html
 

one_and_only2004

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I was looking at these but a mate of mine thought they were only for turbo cars and on a na car it would just be running in negative, but I think he may have been thinking of a boost gauge,

in a commodore vz v6 does anyone know where to tap the vacuum hose into?

Vacuum gauges only read negative pressure IE vacuum. Typically they start at 0 and go to -40. To hook one up you just have to tee off an existing vacuum hose - it's very simple.
 

SUP3RST4R_DJ

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Ok I'll look into getting one like I originally planned next week to tie in with my volts and oil pressure gauge I'm going to be putting in

Thanks all
 

DFECTED

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Im not sure how to upload videos through my phone to here but basically mine sits at around 20 and the more i accelerate then it drops to zero. Once you stop accelerating it sits back on around 20.
 

SUP3RST4R_DJ

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ahk so it basically just measures the air getting into the engine correct? like the induction or in the block? sorry VR38 i couldnt quite tell from your post

and when your just cruising along or idling its only sucking it a certain amount (or pressure) then when you accelerate that number increases (or decreases? cos its in negative?) to say its sucking more air?

am i right?

also are they useful in a efi na vz v6? i know theyd be handy in a carby just not sure on efi and whether they would be a pointless gauge on my vz

thanks

also @ DFECTED are you able to upload to youtube then just post the link here?
 
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