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Thread: MAP sensor question

  1. #21
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    Email sent
    Thanks again

  2. #22
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    Email also sent a couple days ago

  3. #23
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    I guess its a matter of when Eric gets the chance to do it.
    I have had to stop tuning my car due to going too rich when maxing out the sensor.
    Don't really feel like lifting a head.

  4. #24
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    So what part number bosch map sensor is being used for this??

  5. #25
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    I have got the 3.5bar 0 281 002 456
    Which is a 50-350kpa sensor.
    I don't know how it will go as my engine idles in gear 22kpa on the scanner.
    I have also got the 3 bar sensor as well which is 20-300kpa 0 281 002 437.
    I have given Eric both numbers and info so hopefully either will work

  6. #26
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    Do you have to upgrade the boost sensor as well?

  7. #27
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    I very much doubt you will be tuning closed loop boost control with 22+ psi....so forget the boost sensor. Bugsy, don't worry about the sensors range. I would be very interested to know what the factory slope and offset values are for the t-MAP. I suspect it maybe difficult to make sense of the factory calibration (2.5bar) as it relates to the Bosch data. Hopefully Eric understands it and can share the factory values and explain the units.

  8. #28
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    The data for these two sensors that I have is from bosch.
    I don't know what the scales from ford would change.
    But the bosch stuff it pretty Straight forward.
    I sent Eric the link to were I purchased them from.
    They have all the info on the site.

  9. #29
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    Its not that straight forward. Bosch don't just give the data as it is input into the calibration. The slope and offset have to be calculated which is easy enough, but then it needs to be in the correct units that the calibration requires. This is where it sometimes isn't so straight forward. I'm sure Eric is all over it though and i'd like to see the factory data.

  10. #30
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    I'm assuming these are the same. They have 1bar, 3bar, 3.5bar, and 4bar listed as well.


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    Jaime

  11. #31
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    spot on Jaime

  12. #32
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    I purchased the 3.5bar bosch tmap, talking to Eric last night he needs the Slope and intercept Values in inHG Per Volt format

    I have worked out that the slope and intercept formula is y=mx+b

    y=Pressure
    x=Voltage
    m=Scalar
    b=offset

    so the range of the 3.5 bar sensor is

    [email protected]
    [email protected]

    I worked out that y=75x+12.5 using http://www.miniwebtool.com/slope-int...rm-calculator/

    so now if you change x to any voltage you will get the pressure that the sensor will read, i.e

    75x0.5+12.5 = 50Kpa

    75x4.5+12.5 = 350Kpa

    75x2.0+12.5 = 162.5Kpa

    so obviously it will go up in a linear form no matter what voltage is picked, but can anyone help to change the values to inHG Per Volt format for eric to put into my tune?

    is it as simple as saying

    50kpa = 14.76505 inHG @ 0.5v

    350kpa = 103.35535 inHG @4.5v

    thanks, Joe

  13. #33
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    looking at a Holden file, the description for,

    MAP Sensor Linear: the linear calibration of the MAP sensor (slope) in pressure per 5 volts

    MAP Sensor Offset: the offset calibration of the MAP sensor. ie. MAP pressure at 0 Volts

    doesn't exactly clear it up for me,

    75x0+12.5= 12.5Kpa = 3.691262 inHG

    75x5+12.5= 387.5 = 114.429137 inHG

    but the graph that comes with the sensor flat lines at 0.5v and 4.5v

    product-snsr-03088-1772-2.png

  14. #34
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    Peppy,
    You are on to it but need to convert the 75 and 12.5 as well as it is in Kpa. So

    75KpA = 75/100*29.535 = 22.15125
    12KpA = 12.5/100 * 29.535 = 3.691875

    inHg = v * 22.15125 + 3.691875

    Just reading again, intercepts are x = 0 and y = 0 so

    0 = V * 22.15125 + 3.691875 => V = -3.691857/22.15125 = -0.166666

    x = 0, so InHg = 3.691875


    The flat lines are outside of the range, ie below the minimum reading and above the range of the sensor (5V). I would not worry about then too much.

    P.S. Sorry for the not converting to inHg properly in previous versions. I suspect Eric is after the slope = 22.15125 inHg/Volt and offset is 3.691875 which you have down all the work for.
    Last edited by DarrylC; 04-24-2015 at 06:36 AM.

  15. #35
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    Keep up the good work Peppy_t, this would be a real breakthrough for HP Tuners and cause much grief for SCT! I believe we now have the slope and offset for Eric, bugsy and I (and another Territory turbo) will now be able to tune in this range

  16. #36
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    Well there you go, I actually enjoy numbers and your basic math, but this would of taken me a couple more days to work out haha, so thank you Darryl, much appreciated..

    Hopefully Eric sees this, I might email him again to be sure,

    My sensor is about a week away, motor and box are probably 2 weeks away, so it sounds like there is some exciting stuff to come
    Last edited by Peppy_t; 04-24-2015 at 06:48 AM.

  17. #37
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    The pressure conversion looks ever so slightly off there DarrylC

  18. #38
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    Quote Originally Posted by Peppy_t View Post
    Well there you go, I actually enjoy numbers and your basic math, but this would of taken me a couple more days to work out haha, so thank you Darryl, much appreciated..

    Hopefully Eric sees this, I might email him again to be sure,

    My sensor is about a week away, motor and box are probably 2 weeks away, so it sounds like there is some exciting stuff to come
    You guys get extra points if you go ahead and convert the values to double precision (64-bit) float. :-D
    Eric Brooks
    HP Tuners, LLC

  19. #39
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    Quote Originally Posted by Eric@HPTuners View Post
    You guys get extra points if you go ahead and convert the values to double precision (64-bit) float. :-D
    Who's 64 bit format do you want them in? PPC and Hex?

  20. #40
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    Quote Originally Posted by IH8TOADS View Post
    The pressure conversion looks ever so slightly off there DarrylC
    I used MS calc to conversion. If I use Real Calc on Android the KpA -> inHg conversion is 29.52998 (29.53) which is what I use in my programs. Therefore:

    You are on to it but need to convert the 75 and 12.5 as well as it is in Kpa. So

    75KpA = 75/100*29.53 = 22.1475 (was 22.15125)
    12KpA = 12.5/100 * 29.53 = 3.69125 (was 3.691875

    inHg = v * 22.1475 + 3.69125

    Just reading again, intercepts are x = 0 and y = 0 so

    0 = V * 22.1475 + 3.69125 => V = -3.69125/3.69125 = -0.166666

    x = 0, so InHg = 3.69125


    The flat lines are outside of the range, ie below the minimum reading and above the range of the sensor (5V). I would not worry about then too much.

    P.S. Sorry for the not converting to inHg properly in previous versions. I suspect Eric is after the slope = 22.1475 inHg/Volt and offset is 3.69125 which you have down all the work for.

    Given the differences then I don't think it would make have any change on the accuracy of the calculation of the MAP value as the numbers were outside the range of the voltage accuracy.