WannaRace

iTrader: (15)

Well, today I installed my Autometer Phantom series boost gauge...After installation was complete I started the car and saw that the vacuum at idle was at ~15hg, maybe slightly less. However, isn't it usually supposed to be at about 18hg at the least? Something wrong with the gauge? The max boost that I saw on the gauge was 20psi (w/ turbo-back, hi flo, intake, bov). When I turn the car off it sits at about 1psi, so I know it must need calibration, but I'm not about to send it back. Does that have to do with the less vacuum? Thanks for any input.

WannaRace

iTrader: (15)

*bump*

Does anyone have these gauges installed that are getting different numbers?

BadBoyBeltran

iTrader: (3)

Mine is at 10hg when idling and around 15-17 when I let off the gas pedal. It is at around 3-4psi when the car is off.

WannaRace

iTrader: (15)

That's not a good thing...
Anyone else have any input on this? Is it just calibration? Let's hear some more numbers.

WannaRace

iTrader: (15)

Update: It's hit a solid 15hg, maybe 16 at idle and almost into the "0" box when the car is off...like it's calibrating itself weird...

MalibuJack

iTrader: (5)

Is the needle sweeping slowly when you snap the throttle? If it does then there's a small restriction causing it to hold some small amount of vacuum when you turn it off.. If it does not read 0, then the gauge is incorrectly calibrated, or there is a kink in the line somewhere, if you use the plastic capillary tubing its real easy to kink it, and if its kinked, it will read like that all the time.. even if you straighten it back out.. Sorta when you bend a straw it never seems to "Suck up the soda" right..

Now, the best place to read a vacuum source happens to be the line that runs to the Diverter Valve (BOV) Plus there's a short section of soft line on the valvecover about 3-4" long that is easy to T off of..

You might want to exchange just the gauge for another one just to be certain its not defective. but my experience with Autometer (Sportcom or ProComp series) mechanical gauges is their rarely defective.

WannaRace

iTrader: (15)

No, when I snap the throttle the needle moves immediately. I took the "kink" problem into consideration before installing and used a more durable hose instead. I "T"'d the line right before the throttle body since I'm reading boost and vacc.

MalibuJack

iTrader: (5)

Well its a vacuum source off the manifold.. Not sure where you can get a source before the TB but it should work.. As long as it sweeps immediately and doesnt seem to jump slightly at steady RPM's then you should be OK.. My Idle vacuum is typically 10-15 in/hg and my boost is usually (Set with an MBC) 20.5-21psi with an occasional spike of .5psi...

WannaRace

iTrader: (15)

So it sounds normal to me then.. Beside the fact that it doesn't sit quite at zero...when coasting in gear the vacuum is at 19-20 hg...same?

MalibuJack

iTrader: (5)

Yep.. Deceleration does go as high as 20 in/hg...

WannaRace

iTrader: (15)

Oh I feel better! Thanks!

evil8

iTrader: (4)

hmmm...on my just installed autometer boost gauge it read just above 20hg at idle and the most boost I get in any gear is 14 psi. Do you think my gauge is broken? I posted about my problem:https://www.evolutionm.net/forums/sh...threadid=40461

any help appreciated.

Whooopasss

iTrader: (5)

installed mine. 20 on idle and 19 psi at WOT. I T'd it from the fuel pressure reg before the valve. Where did you Tap'd yours?

evil8

iTrader: (4)

I tapped mine on the same location as the pics on this thread:
https://www.evolutionm.net/forums/sh...threadid=36529

iodine23

iTrader: (1)

I idle at about 15in with the AC on, 17in with it off. On decel it can drop to as much as 21in. Boost seems to peak around 19psi, and the car is stock. This is with an Autometer mechanical boost gauge.