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Boost PSI?

JoelW98GTP

JoelW98GTP

New member
I just installed an Autometer boost gauge. I tapped into the LIM just below the s/c snout. My flow mods are in my sig. Ambient air temp is 25*. When I got it finished up, and took it for a drive, I am seeing 4.5psi max. I was expecting too see ~8psi give or take 1psi. Could this be about normal or do you think I have a vacuum/boost leak somewhere? OR, could my Autometer be bad? The reason I question the guage is that my factor gauge registers half full and my autometer will be sitting on 0 during mid throttle acceleration. I know the factory gauge isn't a good means of measuring boost, but being that the factory gauge is seeing boost and my Autometer isn't, and that I was expecting to see higher psi than 4.5, it makes me question the Autometer. It is a used gauge. FWIW, the entire top end of my engine has new gaskets. Thanks in advance!
 


Just got done looking for leaks I may have missed. Don't see any issues anywhere. The gauge reads -22hg on the vacuum end. The car runs strong and smooth. I put a new bbv on it cause the old one was stuck open and didn't run much stronger than a 3.8NA. Now it runs strong and smooth. Are there any really hard to find vacuum lines that I could be missing? I'm still thinking either a vacuum leak or the gauge is bad. Also, the gauge sits at about -3hg when the car is shut off.
 
Or...maybe the gauge is off...because if it is sitting at -3hg OFF, then think about that...it might be about 7.5 psi at WOT...make sense?
 


bluegtp91 said:
Or...maybe the gauge is off...because if it is sitting at -3hg OFF, then think about that...it might be about 7.5 psi at WOT...make sense?
Click to expand...

Thats what I was thinking. Time to get another one. Everything I went over kept pushing me back to the damn gauge. Thanks for the input fellas!
 
IMO, get a smaller PSI gauge...that way the needle sweeps farther :th_king-normal: Got that tip from a good buddy of mine on here. I'd say a 20 psi max gauge should do the trick.

blowfishRus6 said:
im with this guy :th_thumbsup-wink:
Click to expand...

HA!

Beat you too it :th_biggrin2:
 
you cant zero the gauge. my autometer gauge was at -2 in/hg when the car was off. however, mine seemed to read correctly still (or within i pound or so) when WOT.
 


4.5psi boost sounds about right for a stock 3.8 pulley...?
am i really the only one who caught that lol, i had 5 MAX with my stock 3.8 pulley..and that was with my autometer guage. dropped to 3.4 and now see 9psi, and by all means, never NEVER go by your stock boost guage. mine will read full boost, and i wont even be in boost on the autometer guage.
 
i can up to 7-8 depending on weather with my stock pulley with headers and rockers according to my tuner.

stock should see 7~
 


4 PSI is usually a problem with the BBV solenoid. To test it, remove the bottom vac line from the BBV actuator (black canister) and leave that port open to atmosphere. Plug the line, go for a drive, and see how your boost looks.
 
I tried bypassing the bbv. Same thing. 4.5psi. The bbv is fine. I think the car runs too strong to have any boost issues. I'm going to try and borrow a gauge from someone just to verify my suspicions. If thats the problem, then its time to buy a new one. Cacksuckers broke into my MR2 and stole all my gauges, SAFC which was DYNO TUNED with $900 worth of fine dyno tune time, my factory turbo with $700 in upgrades, and umm, in total, about $1000 worth of other stuff. I'mma kill someone.

Thanks for the help guys!
 
my stock boost gause works petty good i dunno what your saying dont go by it lol. it only goes when im actally stepping on gas. if im driving like a old snowbird in there 90's then nothin reads :)
 
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