Boost gauge question

[svtf1417]

I know brands differ from one another, but what's the general consensus on where the needle should sit when the car is off? Anywhere in the zero area? In the very middle? On one of the two extremes of the zero area? Or does it really not matter?

[1turbofocus]

With the car off you chould be at the "0"

Tom

[Dgc333]

Well there are two types of boost gauges. One that reads vacuum and boost and one that only reads boost. Both will read zero when the engine is off but where zero physically is on the dial face is not the same. The vacuum/boost zero will be approximately mid way between the ends of the needle sweep. The boost only gauge zero will be at the be at the beginning of the sweep of the pointer.

[svtf1417]

Ya I thought there was something up with my gauge. And sorry I guess I should have put it's a vac/boost gauge. I'll take a picture when I get home and post it. It doesn't seem to be affecting the performance of it though, I have a 10lb spring in my wastegate actuator and when I was doing WOT pulls with you Tom it topped out right at 10psi

[1turbofocus]

Yes but... if the gauge is sitting on say 3psi when engine off and you get to 10psi that may only be 7psi

Just because you have a 10psi spring doesnt always mean you will have 10psi , it depends on things like how long is you vac line to the WG , is the vac line going to the turbo or intake etc

Tom

[svtf1417]

I ended up going to the girlfriends house instead of home, but luckily I found pictures online of what im talking about.

How I think it should sit with the engine off:


How it really sits with the engine off:

[bespurcell]

Is there a screw or something on the back of it to set it to zero?

[1turbofocus]

Your looking at .5 to 1 psi , I wouldnt worry about it much , so if your seeing 10 you might be 10.5 to 11

Tom