Vacuum (mmHg) at idle correct?

[JDMMA70]

My father and I just installed my boost gauge today to see what my vacuum was at idle. I tried searching to see what the correct vacuum i should be getting i hope im refering to the right term.

My car seems to float between 10 and 20 after a time it will just sit between 10 and 20 and then do the same thing again.

Picture

 

[s383mmber1]

Were do you have it hooked up? Should be directly off the intake manifold.

 

[JDMMA70]

Were do you have it hooked up? Should be directly off the intake manifold.

the line coming out the intake manifold the same line going to the stock boost sending unit

 

[jdub]

Vacuum Gauge Readings

 

[A-to-the-J]

mine is usually between 18-20 in/hg. i was told that was normal.

 

[suprabad]

I believe it's supposed to be 20-21psi at idle and as momentarily high as 25-26psi upon deceleration. There is a link about vacuum readings and how to diagnose with them on supracentrals sig.

 

[Nick M]

17-22" is the rule of thumb. It will vary depending on the engine wear, altitude, ignition timing, etc.

 

[jdub]

There is a link about vacuum readings and how to diagnose with them on supracentrals sig.

A lot like the one I posted above