My boost guage reads from the 20 below the zero to zero when using boost? Shouldnt it start at zero and go up to 20??? Seems like it is backwards-20 to zero rather than zero to 20

 

When idling, or not accelerating, the engine is sucking air in, causing negative pressure. When, accelerating the turbo winds up from the exhaust pressure and pushes air into the engine, causing positive pressure. So the gauge should change between negative and positive, depending on what the engine is doing. If not, take it to the dealer. I think a few people have had problems with their boost gauges.

 

bottom half of the gusge reads vacuum, top is boost pressure. If you aren't seeing any boost pressure, you need to get it checked out.