Making an external MAP input device, need data!

[Redline Motorsports]

I want to make an external 2 or 3 BAR MAP sensor device that I can log through one of the analog 5 volt inputs. Does anyone know where I can get the 0-5v vs. KPA scalings for both a 2 and 3 BAR?

Obviously this is for logging boost on 1 BAR equipped cars.

Thanks

Howard

[Redline Motorsports]

Found this on Delphi's site;

Performance Data for Standard Calibration

Pressure Range
Operating	20 kPa to 102 kPa
Maximum	667 kPa
Full scale accuracy	1.8%

Temperature Range
Operating	-40°C to +105°C
Measurement accuracy	±1°C at 25°C
Storage	-50°C to +150°C

Electrical Characteristics
Supply voltage	5.0 ± 0.1 VDC
Supply current	<10 mADC
Maximum output current	Sink 1 mADC Source 0.1 mADC
Output impedance	<50 Ω
Output voltage	0.25 to 4.85 VDC

Transfer Curve



Can this be used and then half scaled?

[Treurentner]

Hi Howard,

watch robbies page, he found out everything
Part#´s were to get them ...
long time before:
http://www.robietherobot.com/storm/mapsensor.htm

I included a datasheet as pdf (but size is over the uploadlimit so rename it as .pdf)

Marco

[Redline Motorsports]

Finding the parts is easy. I stock both 2 and 3 bar maps. I am looking for the voltage vs. KPA calculation so I can create a calc pid to log off of.

Thanks for the link though.

HT

[Treurentner]

Hi Howard ,

what about this datasheet for 3 bar map (please save it and rename the extension to pdf)?

Marco

[Redline Motorsports]

Thanks for that sheet. Still need to figure out the formula!

[2002_z28_six_speed]

Well, I can tell you one thing. This isn't going to be a one shot equation. You are going to have to make fine adjustments to the equation due to your elevation and daily barometric pressure. Like the GM OS does. You can get close with experimenting, though.

Here are points from the datasheet for a ballpark equation:
Pressure in kPa Average Voltage
40 .631
304 4.914

The linear model would be as follows:
kPa = 61.639*{ADVoltage}+1.105791

Even though you have this data you will still have to plug everything up. See what voltage the 3 bar is running at when the engine off. Write down the kPA displayed on the factory sensor. Use this as your lower data points. Then use the datasheet values for the high data points. You could start the engine to get some data points under vacumn but again error is doubled to 8% under vacumn according to the datasheet.

I wouldn't try to take correctional data with the engine running. That puts the 3 bar MAP into an area with a higher error band.

[johnv]

How about useing one of these sensors and seperate power supply, they come with slope and intercept setup intructions aparently!

http://www.aeroforcetech.com/sensor.html

I'm gonna give one of the fuel pressure sensors and 5v power supplies a shot.

[Redline Motorsports]

How about useing one of these sensors and seperate power supply, they come with slope and intercept setup intructions aparently!

http://www.aeroforcetech.com/sensor.html

I'm gonna give one of the fuel pressure sensors and 5v power supplies a shot.

Getting the parts is not the issue. I am trying to figure out how FS can look at the voltage and convert it to a KPA reading which I can then use a calc pid to show boost.

Isn't there a conversion formula in the generic pid folder that FS uses on a factory 1 bar? The PCM obviously looks at output voltage from the MAP and then takes that voltage to show pressure. What is the formula??

[2002_z28_six_speed]

1 bar 2 bar 3 bar... Delphi has spec'ed them to be 0V-5Vs and linear outputs. This means only the slopes of the equations have changed AKA less resolution for analog to digital converter to see.

Just make a linear equation from 0 to 5 volts that reads out 20 to 300 kPa where:

kPa = (Volts/Kpa)*voltage+correctional factor or
kPa = A*x+c
Y = A*x+c