2002 Wrx stock turbo gauge info

[USMC]

Hey everyone, I'm new to the Subaru wrx turbo gauge. I have an 02 manual wrx and it has the steering column mounted gauge. Anyways I'm just confused how it can read negative pressures? Half the gauge is in negative then the other half is in positive. When I'm drivin around easy it usually reads under 0 in the negative. I also understand that it reads in mPa and not psi. I have a dodge cummins turbo diesel and I know that turbo only reads in positive.. What gives?

[frenziedcage]

Turbocharged cars do not only read positive.. positive is when you are in boost for example when you give it WOT. When you are driving around town under normal driving conditions or on the highway your boost gauge will read negative which means vacuum. This is normal for any turbocharged car the gauge will only read positive when your turbo starts spooling to build boost when the turbo is not spooling it will be in vacuum.

[Donkey]

Manifold vacuum - Wikipedia, the free encyclopedia

Diesel engines and gasoline engines are two different beasts.......