Boost Gauge not accurate??

[wyk3d]

I just finished up a rebuild and am trying to dial in the car. I hear my turbo whistling long before i have zero vac reading on the gauge, maybe at where 5 would be on the vac side. The dash turbo lights light up when i hear the turbo start to whistle. Im assuming my gauge must not be functioning correctly?? Is there a special place your supposed to run the vac line to the boost gauge?? Its currently being run from the first hardline off the vac block which i believe was for the vac canister? Its a phantom gauge from autometer. Any help would be appreciated as the gauge reads 14#s at WOT but if this is plus the 5 when i hear the turbo come in thats 19#.

Dan

 

[turbo buicks]

i think thats normal. my stock turbo makes noise @
~0 boost/vacuum. you got a 51 so i would think it would be amplified due to its size and what not. after all it is nothing but a metal fan spinning in the intake @ many thousands of RMP's

 

[salvageV6]

You can't go by the whistle. My PTE51 whistles nicely at 10 inches vacuum.

It spins anytime theres exhaust, boost doesn't cause the noise.

Both of my VDO gauges read 1.5psi. low to respond to your gauge question. Tested with a calibrated Omega $400 gauge.

I suspect people are running a bit more boost than they realize sometimes.

 

[FTC]

i have the same thign happening to me. i just put a autometer gauge in and its take a while on the gauge to show its boosting. like the stocker will be at 2-3 and the autometer will jsut be getting to 1. so i think thats normal for it to happen, cause i know the stock boost gauge is horribly inaccurate.

 

[turbojimmy]

'taint the whistle

As mentioned, the whistle doesn't tell you much. My 51 whistles at idle if you stab the throttle, but no boost on the gauge. I don't think my Autometer gauge is accurate. Last time out to that track, it said I was running 24 psi on 94 octane w/ a 98 octane chip and no knock. I just tune it to the 02 sensor and knock sensor. I can see "patterns" from the boost gauge, like if I'm creeping, but the values it gives me are off I think.

Jim