View Full Version : boost gauge reading 20 lbs vaccum?

02-10-2008, 09:22 PM
i installed a new autometer boost gauge and i drove my car for the first time and it was reading between 10 and 20lbs of vaccum...
if it helps, i have the t25 turbo that comes with a redtop sr20
why is it doing thatt??

02-10-2008, 10:21 PM
If you're just cruising the gauge is going to read vac, if you put it to the floor you should see it hit full boost between 2900-3200 rpm. At idle it will probably read somwhere around 20-25psi vac, because there is no load on the engine.

02-11-2008, 12:09 AM
What you are seeing is completely normal. My car idles at ~21psi vacuum and unless I'm over 1/4 throttle it will stay on the vacuum side. If you are saying that you are full throttle and the gauge won't come out of vacuum then theres either a problem with the line to the gauge or the gauge itself.

02-11-2008, 01:18 AM
its actually mmHg of vacuum. which 25mmHg is about 0.5psi if my asian genes serve my calculations correctly.