Help needed to scale Apexi map sensor
Jul 22, 2010, 02:51 PM
#1
Help needed to scale Apexi map sensor
Hi guys
I have just fitted an Apexi map sensor (3bar) to my Evo 8 and wired it via ecu
Can any 1 help with the correct scaling for evoscan?
My atm is 14.5 psi
It is reading and working in evoscan, just not right, i am reading near 3 psi with key on and engine not running! Reads about 3 -4 psi out compared to my Gizzmo msibc, so the scaling is wrong
Thanks
Phil
I have just fitted an Apexi map sensor (3bar) to my Evo 8 and wired it via ecu
Can any 1 help with the correct scaling for evoscan?
My atm is 14.5 psi
It is reading and working in evoscan, just not right, i am reading near 3 psi with key on and engine not running! Reads about 3 -4 psi out compared to my Gizzmo msibc, so the scaling is wrong
Thanks
Phil
Jul 22, 2010, 05:49 PM
#5
PSI = 0.8531 * x - -79.77
KPA = 5.8824 * x - -450
Scaling for SD
PHP Code:
<scaling name="BoostErrorPsi Apexi3barMAP" units="psi" toexpr="(x-128)*0.0354" frexpr="(x/0.0354)+128" format="%.1f" min="-15" max="15" inc="0.1" storagetype="uint16" endian="big"/>
<scaling name="PSIa16 Apexi3barMAP" units="PSIa" toexpr="x*0.1418-4.53" frexpr="(x+4.53)/0.1418" format="%.1f" min="0" max="32" inc="0.2" storagetype="uint16" endian="big"/>
<scaling name="PSIa8 Apexi3barMAP" units="PSIa" toexpr="x*0.1418-4.53" frexpr="(x+4.53)/0.1418" format="%.1f" min="0" max="32" inc="0.2" storagetype="uint8" endian="big"/>
<scaling name="kPa Apexi3barMAP" units="kPa" toexpr="x*0.4888-150" frexpr="(x+150)/0.4888" format="%.1f" min="0" max="350" inc="0.4888" storagetype="uint16" endian="big"/>
Jul 22, 2010, 05:53 PM
#7
Excellent
PSI = 0.8531 * x - -79.77
KPA = 5.8824 * x - -450
Scaling for SD
PSI = 0.8531 * x - -79.77
KPA = 5.8824 * x - -450
Scaling for SD
PHP Code:
<scaling name="BoostErrorPsi Apexi3barMAP" units="psi" toexpr="(x-128)*0.0354" frexpr="(x/0.0354)+128" format="%.1f" min="-15" max="15" inc="0.1" storagetype="uint16" endian="big"/>
<scaling name="PSIa16 Apexi3barMAP" units="PSIa" toexpr="x*0.1418-4.53" frexpr="(x+4.53)/0.1418" format="%.1f" min="0" max="32" inc="0.2" storagetype="uint16" endian="big"/>
<scaling name="PSIa8 Apexi3barMAP" units="PSIa" toexpr="x*0.1418-4.53" frexpr="(x+4.53)/0.1418" format="%.1f" min="0" max="32" inc="0.2" storagetype="uint8" endian="big"/>
<scaling name="kPa Apexi3barMAP" units="kPa" toexpr="x*0.4888-150" frexpr="(x+150)/0.4888" format="%.1f" min="0" max="350" inc="0.4888" storagetype="uint16" endian="big"/>
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Jul 22, 2010, 05:56 PM
#8
Feel free to use my scaling chart when you determine the min and max voltages.
https://www.evolutionm.net/forums/at...ling-chart.zip
Jul 22, 2010, 06:09 PM
#9
That was for the 3 bar sensor with the same voltage scale but it doesn't work out for you if 2volts is 1 bar. So without a voltage map we are still lost :P
Feel free to use my scaling chart when you determine the min and max voltages.
https://www.evolutionm.net/forums/at...ling-chart.zip
Feel free to use my scaling chart when you determine the min and max voltages.
https://www.evolutionm.net/forums/at...ling-chart.zip
Jul 22, 2010, 07:06 PM
#13
Sorry the graph didnt work out, but with some googling i found this:
original link: []forums.bimmerforums.com/forum/showthread.php?t=1332063
I'll stop trolling now lol. Good luck.
EDIT: CRAP! lol it matches my graph! trial and error time.
EDIT2: just bracket the whole equation and subtract 3 heh. j/k. there's a scaling in the bimmer forum. try that. it seemed ok.
me and my edits:
EDIT3: try 0.14455*x-14.5. if that doesn't get you close, the apexi sensor is out of spec or you must compensate for the how the ecu is reading it (the extra .5v that you get). sorry for the late reply. Good Luck!
SiGmA10-28-2009, 09:32 PM
Okay I pulled my AVCR out today to sell it (Anyone want to buy it?
) and took readings for you. I am listing both the measurement from my gauge, as well the as AVCR's reading, and voltage as measured with my Fluke.
20 inHg / -533 mmHg / 0.80v
0 inHg / -20 mmHg / 1.50v
5 psi / 0.30 KgCM^2 / 1.82v
10 psi / 0.65 KgCM^2 / 2.17v
15 psi / 1.02 KgCM^2 / 2.54v
20 psi / 1.40 KgCM^2 / 2.91v
I hope that helps Collin.
Oh, and does anyone want to buy my AVCR?
Okay I pulled my AVCR out today to sell it (Anyone want to buy it?
) and took readings for you. I am listing both the measurement from my gauge, as well the as AVCR's reading, and voltage as measured with my Fluke.20 inHg / -533 mmHg / 0.80v
0 inHg / -20 mmHg / 1.50v
5 psi / 0.30 KgCM^2 / 1.82v
10 psi / 0.65 KgCM^2 / 2.17v
15 psi / 1.02 KgCM^2 / 2.54v
20 psi / 1.40 KgCM^2 / 2.91v
I hope that helps Collin.
Oh, and does anyone want to buy my AVCR?
I'll stop trolling now lol. Good luck.
EDIT: CRAP! lol it matches my graph! trial and error time.
EDIT2: just bracket the whole equation and subtract 3 heh. j/k. there's a scaling in the bimmer forum. try that. it seemed ok.
me and my edits:
EDIT3: try 0.14455*x-14.5. if that doesn't get you close, the apexi sensor is out of spec or you must compensate for the how the ecu is reading it (the extra .5v that you get). sorry for the late reply. Good Luck!
Last edited by evoredy; Jul 22, 2010 at 08:49 PM.