Maybe this has been covered a lot before, but I haven't seen a dedicated thread in the X section.

At any rate, the values I see in Evoscan on a log report about 2-3psi higher than my Omori electric boost gauge and also about 2-3psi higher than the dyno.

I have tapped multiple sources with the gauge, so I believe Evoscan to be the one in error.

Anyone else notice this?

 

evoscan reads at the manifold, correct? which is coming from the ecu? i would trust evoscan. your not relaying on vaccum hose connections.

evoscan showed that my car was hitting 26 and holding 25. the dyno showed 24 spike and 23 hold.

either way, if your no knocking, believe whichever you want, just dont knock.

but im sure someone else had much better experience with this then me. and you will probably get a real answer. not just theory.

 

I've actually found that EvoScan reads about dead on as far as I can tell. My Autometer boost gauge sits between 1 and 2 psi when the car is off depending on the barometric pressure and it has read 1-2 psi higher than hookups to a dyno. It's possible the EvoScan output might still be +- .5 psi as not all sensors are going to be dead on accurate but mine seems to be quite good.

When you flip on the ignition but don't start the car, what does your electronic boost gauge read compared to Evoscan? You could determine if it's 2-3 psi off at Atmospheric pressure and then just play with the equasion to calibrate it (Like add 2.5 psi and zero it out so that it reads more accurate). You could also swap the MAP sensor with someone to see if there is any difference.

 

evoscan might be .5 psi off as the formula isn't perfect.

HOWEVER what elevation are you at?

 

I am at 680', so it should be right.

I have tried different boot gauges in the past, Autometer and Defi read crazy high when they go beyond 21psi. I like Omori because it has always matched the dyno, plus its the only gauge I ever had that zeroed out properly.



This matches my gauge, but on the same run, the logger will read that midrange at almost 27psi.

I will go ahead and say I believe the dyno. I am not running a true 27psi in the midrange like Evoscan suggests on pump gas and not seeing knock.

I think the post from meat EVO is the one that matters for the safety of the car: "either way, if your not knocking, believe whichever you want, just dont knock"

 

Reads spot on with our dyno and a zeitronix map sensor.

Do you have your Evoscan formula set correctly for your altitude?

 

Bryan,

I haven't changed it at all, so whatever reads defaut is what I have.

Thanks for the input guys, I'll look into this.

 

Do what hiboost mentioned above. Key on car but don't start it.

Log boost in evoscan. It should be as close to 00.00 as possible, if not, adjust formula in evoscan.

I'm basically at sea level so using 14.6-14.7 made mine as close as possible.

 

Thank you all! Will do.

 

I've compared Ecutek's logged boost pressure (from the X's map sensor) to my innovate and the same dyno Noize is talking about on the same pulls and find them all to be within 1 psi.

Evoscan is not reading correctly for his car. Can't say about others. His was deff reading about 2.5 - 3 psi higher than the dyno's 5 bar which has proven to be very accurate. Even if the baro needs to be compensated a little it should not be as far off as his seems to read.

 

Wouldnt that point to something on his car rather than a formula in evoscan then? If others log correctly with evoscan and he said he didnt change anything, then i would look at either the map sensor, maybe the barometer, boost leak......something along those lines.

 

Logger with key on, car off reads almost dead on at -0.13.

Looked at most recent logs, I saw 25psi just for a smidge in the 3600rpm range. I bet its really close, within a pound now or so. Dunno what was up the other day, but it seems alright or close enough.

Thanks again guys.

 

I have a Zeitronix multigauge as a boost gauge and Evoscan seems to read pretty close to what the gauge says. I have logged many cars with this setup and it seems pretty consistent. If you are having issues, I would question the frequency of how the gauge reads and how your Evoscan is setup. Sometimes aftermarket gauges have curve smoothing on them so the signal appears more stable.

 

I posted this in the Logging thread on Aug 1 2009:

On Sunday I logged mode23 boost and the ZT2 boost with the medical grade Kavlico 3.5 bar MAP sensor I could not log the rpm with the ZT2 since the wire is not connected. I ran Evoscan and the ZT2 logger at the same time and logged the boost for the same 4th gear run. I compared the peaks and valleys of both boost curves and can confirm an almost exact overlap between the two.

I have compared the JDM MAP sensor to the GM 3-bar MAP sensor on my Evo 9 and they were very close.

Good to know that mode 23 boost is accurate



I am at sea level and the formula is set to 14.7 barometric pressure.

 

Oh wow, great info. I hadn't read this post till now and I'm glad I did.

I'm gonna check tomorrow to make sure my formula is dead on.

-Ray