b20accord

Well ive been making a few runs and my boost guage reads about 7 psi, but my safc will show about 27 kpa which converts to 3.91psi Which one should i believe? My safc or my boost guage?? My boost guage has given me crap in the past so thats why i dont know which one to believe

JDMFantasy2K

i've been noticing the same thing on my vafc. I'd def trust the boost gauge first since it is mechanical and the vafc is just trying to make a reading from the MAP sensor (i believe).

USS

Map sensors usually have a 0-5v range in which they read vacuum and boost. I think your SAFC is calibrated for your map sensor.

sohc_mshue

Yea 27kPa is about what you should read at idle. About -21.97 in/HG

MikeJ-2009

I noticed a 2-3 psi difference between my old boost gauge and vafc. Then I went to the dyno and the dyno read 2-3 psi more than either of them.


Everything is wrong.

bumblezc

Samething with my boostgauge and Laptop, I trust the laptop seeing as it reads from the map sensor, and that what the ECU uses for mapping.

Reddy

I've had 3 different readings from my AFC, boost gauge and boost controller. I trust the boost controller the most

b20accord

damn, lol. I really dont know which to believe now lol. I think i might just go with my boost guage considering thats what it is specifically for lol. Thanks for the help guys.

45psi

add them both together and divide by two

Tom-Guy

You can't trust a mechanical gauge, not unless it's calibrated lab equipment. Prepare to pay some jack, and it's not a service grade gauge meant to be knocked about and vibrated a lot. Unless you *really* pay some jack.

You can't - wholly - trust the MAP sensor based reading as a lot of stuff can throw that off, too. Wierd voltage/resistance quirks in your wiring. Tolerance/calibration of the MAP sensor itself.

Personally, I pay the most attention to what the ECU logs tell me. While I doubt their exact calibrations for reasons stated above, I know exactly what timing and fuel values the ECU is operating off of. ~3 psi variance means jack ----, so does "how much boost you run, dog." I'm worried about whether or not the system performs consistently, hits the desired psi figure without variance or uncontrolled boost creep.

I'm also worried about when I get a ******* next. It's been a minute.