I bought a Black Faced Defi D boost gauge.
I followed this helpful instruction.
https://www.evolutionm.net/forums/sh...ad.php?t=80842

My question is how do I know if my boost gauge works properly?

When I idle, the vacuum is about 19 to 20 psi. I searched the forums and it seems like that works ok.

When I am driving, if I were to accelerate normally (not mashing the pedal to the floor) to above 4,000 rpm, is the boost gauge supposed go to boost range? When I do that I don't see the needle go near the 5 psi in boost. It drops and hovers in the vacuum range.

But when I accelerate quickly (mashing the pedal to the floor), I see the boost rise up to 19psi. That I know it works.

Is that normal?

 

if you are stock you are probably fine. You will find stock the car usually is in boost or out and not much in between. It will go into boost as the car gets into more load. But if you don't acc hard it won't boost much at all stock.

 

Thanks. That's good to know. I thought there was something wrong with the boost guage.

 

The one other thing that you can check just to be sure is when your car isnt' running the gauge must be sitting at zero. If the needle doesn't sit on zero it will be off as well but if it does I am 99% sure it is working correctly. Just somthing else I wanted to mention.

 

Most of the time you will not be in anything other than vaccum since there is no load on the car unless you are giving it a good amount of throttle. When you hit it you will see boost jump up, and as soon as you let off the throttle you will see it dip back into vaccum. You should also notice that if you are in neutral and rev it up you wont be able to generate much psi. It's all related tot he amount of load on the car and the amount of throttle.