Nitr0EngiEx
Member
has anyone tuned a new MAP sensor yet.
the cobb ap manual says this:
My sensor Reads -> (50 kPa @ 0.5V , 350 kPa @ 4.5V)
but that is just how the ECU calculates boost, I need a ******* equation to find out what Scalar a/b is and the offset not what the damned s*** is factory >.<
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A member of another forum suggested the info I need is:
I did some math of my own based on his numbers and Scalar A and the offset seem to match, however I cannot confirm the Scalar B It does not seem to be correct.
When I Make Scalar B X and use the info I know about my sensor that .5 volts = 50 kpa, and use the offset 12.5 and scalar A is 75 then I get x=1.66~ for .5 volts
and when i do it for 4.5 volts giving kpa 350 offset 12.5 and scalar A is 75 then I get x=1.074074074074074
2 Different values, they cant both be correct and they are certainly different. someone please shed some light on the Correct way to calculate this
if you go by the Scalar B you have provided which is one according to the Math it Claims at .5Volts my Sensor will read 25 KPA, which is wrong. its supposed to be 50
So If i Backwards look for Scalar B we get this again
according to this math scalar b should be 1.666666666666667
but then when calcing 4.5V@350kpa
Then scalar b is now 1.074074074074074
the cobb ap manual says this:
Code:
Input: MAP Voltage (0-5)
Output: Absolute Pressure (kPa)
(((MAP Voltage) * (Scalar A)) * Scalar B) - Offset
STOCK SETTINGS for 2.5 Bar STOCK sensor
Scalar A = 230
Scalar B = 0.23529412
Offset = 1.647My sensor Reads -> (50 kPa @ 0.5V , 350 kPa @ 4.5V)
but that is just how the ECU calculates boost, I need a ******* equation to find out what Scalar a/b is and the offset not what the damned s*** is factory >.<
Code:
http://www.ontronic.com/products/doc/Sensors_mapt.pdf=============================================================================================================
A member of another forum suggested the info I need is:
Code:
Scalar A = 75
Scalar B = 1
Offset = 12.5I did some math of my own based on his numbers and Scalar A and the offset seem to match, however I cannot confirm the Scalar B It does not seem to be correct.
Code:
(((MAP Voltage) * (Scalar A)) * Scalar B) - Offset
((.5*75)*1)-12.5=25
((4.5*75)*1)-12.5=325
((.5*75)*x)-12.5=50
37.5x-12.5=50
37.5x=62.5
x=1.666666666666667
((4.5*75)*x)-12.5=350
337.5x-12.5=350
337.5x=362.5
x=1.074074074074074
Stock ecu settings provided by ecu w/stock Map using 1 volt reference
((1*230))*.23529412)-1.647=x
(230*.23529412)-1.647=x
54.1176476-1.647=x
x=52.4706476
52.4706476 KPA @ 1 Volt
Stock ecu settings provided by ecu w/stock Map using 5 volt reference
((5*230))*.23529412)-1.647=x
(1150*.23529412)-1.647=x
271.312738-1.647=x
x=269.665
269.665738 KPA @ 5 Volts
Stock ecu settings provided by ecu w/stock Map using 5 volt reference
((4.5*230))*.23529412)-1.647=x
(1035*.23529412)-1.647=x
244.1814642-1.647=x
x=242.5344642
242.5344642 KPA @ 4.5 VoltsWhen I Make Scalar B X and use the info I know about my sensor that .5 volts = 50 kpa, and use the offset 12.5 and scalar A is 75 then I get x=1.66~ for .5 volts
and when i do it for 4.5 volts giving kpa 350 offset 12.5 and scalar A is 75 then I get x=1.074074074074074
2 Different values, they cant both be correct and they are certainly different. someone please shed some light on the Correct way to calculate this
Code:
((.5*75)*1)-12.5=25
((4.5*75)*1)-12.5=325if you go by the Scalar B you have provided which is one according to the Math it Claims at .5Volts my Sensor will read 25 KPA, which is wrong. its supposed to be 50
So If i Backwards look for Scalar B we get this again
Code:
((.5*75)*x)-12.5=50
37.5x-12.5=50
37.5x=62.5
x=1.666666666666667according to this math scalar b should be 1.666666666666667
but then when calcing 4.5V@350kpa
Code:
((4.5*75)*x)-12.5=350
337.5x-12.5=350
337.5x=362.5
x=1.074074074074074Then scalar b is now 1.074074074074074
Some sensors require positive offset values (like the stock sensor) and some (like the one you're using) require negative offset values. I confirmed with an engineer that the software incorrectly sets the minimum floor to 0 (non-negative numbers only). We will be generating and releasing a new build of the software to address this ASAP; I will let you know when we have an update available.