Boost #'s

[mebcop]

I am having an inconsistancy problem.... My gauge reads 27psi, my W/M controller is reading 25psi and my ems using the 3.5bar sensor is reading 22psi..... which one is accurate??? I find it weird also that the gauge reads 20psi of vacuum and my map sensor only reads 9??? I've heard the map sensor reads vacuum differently, but why and how?

[mebcop]

hmmmm.... no suggestions.....

[onthedwnlow]

the gauge and ems will read diffrent i asked the same thing a while back.....one is in mmg and the other hg.....2 diffrent ways to read vac......boost should be the same......

i would trust the ems's reading of the boost as long as there is no boost leak between the intake mani and the sensor......

my gauge and ems read spot on from 0-max boost

[JANNETTYRACING]

Quote: Originally Posted by mebcop

I am having an inconsistancy problem.... My gauge reads 27psi, my W/M controller is reading 25psi and my ems using the 3.5bar sensor is reading 22psi..... which one is accurate??? I find it weird also that the gauge reads 20psi of vacuum and my map sensor only reads 9??? I've heard the map sensor reads vacuum differently, but why and how?

What map sensor did you choose in your setup?
Did you use the map sensor wizard?

Sounds like something is not scaled properly.

Ted.

[mebcop]

I have the AEM 3.5bar map sensor and it is selected in the wizard. It does seem like it is not scaled right, but it's all aem stuff......

[05plsrt4]

My autometer ultra-lite gauges seems to be way off from the EMS too. I dont know which one to trust.

I'm also running the 3.5bar map sensor

[duster360]

Quote: Originally Posted by mebcop

I am having an inconsistancy problem.... My gauge reads 27psi, my W/M controller is reading 25psi and my ems using the 3.5bar sensor is reading 22psi..... which one is accurate??? I find it weird also that the gauge reads 20psi of vacuum and my map sensor only reads 9??? I've heard the map sensor reads vacuum differently, but why and how?

imo, you need to forget about Gauge pressure when tuning it will just screw you up. 0 psig will fluctuate with altitude and barometric pressure.

Absolute pressure = ambient pressure + guage pressure

Your map sensor reads absolute pressure usually its in KiloPascals(KPa)

9Kpa =~ 20 in-Hg vaccum (NOT 20 psi)

[lilmike0450]

yea mine is like that too. I just datalog lots to tune and my boost is where I want it on the EMS....forget the gauge.

[nutz]

psia-psig

[duster360]

Quote: Originally Posted by nutz

psia-psig

psia-psig = ambient/barometric/atmospheric pressure

14.5psi ambient + 15psig(auge) = 29.5psia(bsolute)

[never2muchboost]

ok all you conversion nerds...calm down


hes asking about the difference between the gauge ,meth controller and ems.
at 27 psi
where is your map sensor mounted? do you hve it running off a vac line or mounted on the intake

[mebcop]

I have the Rage adapter and it's in the stock location on the IM. It's just kinda scary, cuz my tuner tuned the car to 26psi on the ems.... which is over 30 on the gauge!!!

[never2muchboost]

Quote: Originally Posted by mebcop

I have the Rage adapter and it's in the stock location on the IM. It's just kinda scary, cuz my tuner tuned the car to 26psi on the ems.... which is over 30 on the gauge!!!

well that would explain why you made decent power on such a crappy tune lol. hey do me a favor and email me the current calibration and i will make some adjustments to it.i have been meaning to do it but i was laid up in bed for 5 days and now im playing catch up

[mebcop]

Jay, I sent you that map.... let me know when you get a chance to look at it. THANX MAN!!!

[never2muchboost]

ok i emailed you back a map along with a template to log.i dont know how its going to run at first because your map was so jacked so lets start at the beginning and try to work our way forward.if you can drive around for a little while on that map and get a couple good logs i cant get it alot closer on the next one