Originally Posted by
tabetha
It's the OPOSITE of a boost gauge, boost is Positive pressure, ie being forced in by the big air pump(turbo), vacuum is Negative and what exists when the engine is sucking, caused by the pistons going down the bores creating a vacuum behind them which sucks in the air.
tabetha
i follow you
but what i ment was sitting at idle in a turbo car reads -10/15 psi so on a vacum guage it would reed idle then as postive boost comes in it will read poor on vacum guage i did understand what you ment and understand how a vacum guage works turbo positive pressure so on vacum guage it would be reading as if there was air getting into the system and indicate poor vacum on the guage but is there any benerfit in having a vacum guage on a turbo engine would it help to notice an airleak as such
mark2