y-man

I just installed my Turbosmart boost controller and also an Autometer boost gauge in my car and I'm getting negative boost readings of ~-13# at idle and slightly above idle. What did I do wrong? I don't expect much boost (if any) at that low of an RPM, but certainly not -13#. I used the port at the back of the manifold wich I "T" 'd as my source (separate boost lines going to each unit). The MAP sensor is, incidently, reading ~7#.

Any ideas?
Thanks
Matt

Brains

iTrader: (7)

You'll definitely read vacuum at idle.. If you didn't, you A/C controls wouldn't work and you'd have no power brakes...

Ferocity02

iTrader: (60)

Your car makes vacuum at idle. Vacuum = absence of air, which implies a negative pressure. Normal air presure is 14.7psi. Your boost gauge is calibrated to read 0 at normal air pressure, when it is really 14.7psi. Thus vaccum would be -14.7psi according to your boost gauge. You should read negative pressure 95% of the time. Only goes positive when you goose it and build boost.

y-man

Okay, I understand the whol 14.7PSI at sea level, that makes sense about how the boost gauges are referenced. Should I see a correlation though between the boost gauge readings and the MAP sensor value?