HELP HELP 3 bar question

B16T · Post by **B16T** » Tue Jul 25, 2006 3:42 pm

The gm sensor i got was a 1 bar can someone give me the GM part# for the motec 3 bar so i can get this thing going Thanks

Post by **Spunkster** » Tue Jul 25, 2006 4:59 pm

Here is how to calculate the scalar and offset for a MAP sensor.

1. Find the minimum and maximum voltage and absolute pressures.

2. Convert the pressures to mbar.

3. Subtract the minimum and maximum voltages to find the range, then do the same for the pressures.

4. Divide the pressure range by the voltage range to calculate the scalar.

5. Multiply the minimum voltage by the scalar to calculate the offset. Note that a positive voltage gives a negative offset.

Example for a 3.5 bar MAP sensor:

1. For a 3.5 bar data sheet:
0.5V @ 0 kPa (absolute)

4.5V @ 345 kPa (absolute)

2. 345 kPa = 3450 mbar.

3. Voltage range = 4.0V, pressure range = 3450 mbar.

4. 3450 / 4.0 = 862.5 = scalar

5. 862.5 x 0.5 x -1 = -431.25 = offset

So scalar = 862, offset = -431

Plug in the minimum and maximum voltages to check your work:
0.5V x 862.5 - 431.25 = 0 mbar @ 0.5v

4.5V x 862.5 - 431.25 = 3450 mbar @ 0.5v

If you have trouble then draw a graph and extrapolate the lines until they cross the pressure axis.

B16T · Post by **B16T** » Tue Jul 25, 2006 8:45 pm

So that example you gave seems to be what the AEm 3.5 is , could i just use one of the other 3 bar settings or does the gm need its own?

turbosi92 · Post by **turbosi92** » Wed Jul 26, 2006 9:59 am

B16T wrote:So that example you gave seems to be what the AEm 3.5 is , could i just use one of the other 3 bar settings or does the gm need its own?

what part number is on your GM 3 bar?

B16T · Post by **B16T** » Wed Jul 26, 2006 3:53 pm

Part # is pbt-gf30 9576-22