My car only runs around -19 vacuum when at idle. I have changed from the stock bov to a synchronic bov in hopes that I just had a worn out factory blow off valve, but there is no change in vacuum...my idle improved slightly (but i think this might be due to the synchronic valve in the open position at idle) I have checked and checked and checked for a vacuum leak and have yet to find one. I've replaced several lines, sprayed everything down with starter fluid, re-checked all of my boost clamps etc....Is there something i'm missing here? It seems like I should be able to locate this issue no problem. The car boosts great, but I'm just worried that i've missed something. Are there any common fail points that I should re-check?

Note: both blow off valves are making the same noise. After looking at youtube it would seem that it should just be ONE pssshhh. Mine sounds like psssshpssshhhpssshhh.

every car varys a bit.
the BGB says -18 - -22hg is normal, so unless your noticing other problems, i wouldnt worry about it.
jenns car starts ~ -16 - -18hg cold, then makes a bit more warm ~20 or so.
what kind of gauge you using? and how accurate is it?

youre fine ben, 19-20 is normal, my first swap ran 19 vac. using an auto meter boost gauge. right now, mine on the other hand is reading 15-16 for some strange reason...

Its an auto meter I can't imagine its very accurate. Defi is a bit out of my price range.

Altitude also plays a factor in idle vacuum.

In Calgary (elev. approx. 1,000 m) my car idled at around 16 in when warmed up.

In Vancouver (sea level) I consistently get around 19-20.