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OBD1 8bit M Bar

Library.OBD1_8bitMBar · r1.1 · · bigwig

Assuming that the stock map sensor's maximum reading is 1764 Mbar, the formula to convert MAP byte value is ((1764 / 255) * [[OBD1]] _8bitMBar / 2). When the rom's map value has been [[uncorked]], simply remove the last division which results in the formula ((1764 / 255) * [[OBD1]] _8bitMbar).
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OBD1 Honda Map Sensor Information


Stock Map:5/255*((Raw/2)+Fuel Cut)
Boost Map: volts=(5/255)*(Raw+fuelcut)
**Fuel cut stock is 24 and editable at 0x4dcc**

2.85 V=0
"1.0V=20"
(20-0)/(2.85-1)=m
(y-0)=20/1.85(x-2.85)
inHG=20(volts)/1.85-30.81

2.85V=1013mbar
"1.0 V=336mbar"
(1013-336)/(2.85-1)=m
(y-1013)=365.9(x-2.85)
mbar=365.9(volts)-29.9


Raw

0

24

48

80

128

176

208

224

240

256

Volt

0.471

0.706

0.941

1.255

1.725

2.196

2.51

2.667

2.824

2.98

mbar

142.3

228.4

314.5

429.3

601.5

773.6

888.4

945.8

1003

1061

 

Raw

0

12

24

40

64

88

104

112

120

128

Volt

0.471

0.706

0.941

1.255

1.725

2.196

2.51

2.667

2.824

2.98

mbar

142.3

228.4

314.5

429.3

601.5

773.6

888.4

945.8

1003

1061

Raw values shown above are for a P72/75. Most if not all OBD1 ECU's follow this rule though so its just a matter of plugging in different raw values. Feel free to edit anything that is deemed incorrect.

-- bigwig - 21 May 2005

Attachment: Modify: Size: Date: Who: Comment:
mapsensor.jpg mod 10674 21 May 2005 - 03:46 bigwig  

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