WRX Turbo Gauge Indication?

I assume it also shows vacuum and should read anywhere from 0--7 or whatever amount of vacuum the WRX will produce. At the RPM where the turbo kicks in it should show boost and this should rise as a function of RPM/throttle position until it reaches the max boost the WRX will produce. If you ever wan to use an aftermarket boost controller I recommend a better gauge. TG

I've heard the stock sensing line can be restrictive at best. NASIOC or ScoobyMods has a section on upping the size of the lines to get better (read quicker, steadier) readouts. Mike

I haven't had a problem with my '03 with stock gauge. It moves with the tach and at a fixed RPM, the needle is still.

It sounds like your gauge is normal, you just have to learn how to read it. At idle, light throttle/crusing, and decelerating, the gauge will show vacuum. The vacuum at idle will normally be steady but may change slightly if the AC is running (you'll see it move as the compressor cycles and changes the engine load), you turn the wheel when stopped or parking (power steering pump also loads the engine), a heavy electrical load kicks in (fans, etc.). When decelerating in gear with your foot completely off the gas you'll see more vacuum than at idle, this is normal. As you accelerate and place a heavier load on the engine, you'll see the gauge move out of vacuum, past zero (which represents atmospheric pressure) and into positive pressure or boost. The amount of boost you see depends on a few things, including what gear you're in, RPM, engine load and throttle position. The factory boost control system won't give you full boost until you get pretty far into the throttle, up to that point you'll get wastegate pressure or about half of full boost. The gauge is calibrated in Mpa, which is a metric scale for pressure. .05 on the gauge corresponds to about 7 PSI, .1 about 14 PSI. Coincidentally on the WRX 7 PSI is wastegate pressure, and 14 PSI is approximately maximum boost.