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Boost sensor 2 or 3 bar?

Stock is a 2 bar MAP.

1BAR measures up to 1 atmosphere which means it can only measure vacuum as 14.7PSI is atmospheric pressure.
2BAR measures up to 2 atmospheres which is 29.4 PSI or 14.7 PSI over pressure at sea level
3BAR measures up to 3 atmospheres or 44.1 PSI or 29.4 psi over pressure at sea level
 
Yup, figured it was a 2 bar....needed confirmation though.

I'm looking to tap into the sensor in order to run a digital boost guage.

I believe it will still work, just need to know the sensors specs so I can calibrate it.....

Or, I wonder if a 3 bar can be substituted for a 2 bar? That would probably just confuse the PCM as the values would all be off I think...
 
It operates on 5V, 5V or thereabouts 4.75V to the PCM is like 2 bar

0 would be 0, but with atmospheric it should always be above 1V according to DTC manual. So Im not sure if its linear, like 2.5V is 1 bar, if so you should be able to go out and check it with a voltmeter with the ign on.

I might go check it tomorrow.
 
buddy said:
It operates on 5V, 5V or thereabouts 4.75V to the PCM is like 2 bar

0 would be 0, but with atmospheric it should always be above 1V according to DTC manual. So Im not sure if its linear, like 2.5V is 1 bar, if so you should be able to go out and check it with a voltmeter with the ign on.

I might go check it tomorrow.
Click to expand...

That's what I'm wondering.

If it's linear, it's simple to figure out.....
 
Go put a voltmeter to it with ign on, will give you what 1 bar voltage is then with that can determine linearity or write the equation to match it I suppose.
 
Been a few years since I've used this data, but the calibration curve on the common GM 1, 2, & 3 bar MAP's are posted on many aftermarket piggyback or standalone ECM forums.

The chart below describes the pressure-to-voltage relationship of the stock GM Turbo MAP sensor (2 bar):
Manifold Pressure
(relative sea level / absolute) 2 Bar
MAP Output
14.31psi / 29.01psi 4.90V
14.00psi / 28.70psi 4.84V
13.00psi / 27.70psi 4.67V
12.00psi / 26.70psi 4.50V
11.00psi / 25.70psi 4.33V
10.00psi / 24.70psi 4.16V
9.00psi / 23.70psi 3.99V
8.00psi / 22.70psi 3.82V
6.00psi / 20.70psi 3.47V
4.00psi / 18.70psi 3.13V
2.00psi / 16.70psi 2.79V
0.00psi / 14.70psi 2.45V
5.00inHg / 12.24psi 2.03V
10.00inHg / 9.78psi 1.61V
15.00inHg / 7.33psi 1.19V
20.00inHg / 4.87psi 0.77V
25.00inHg / 2.41psi 0.35V
29.10inHg / 0.40psi 0.02V

MAP sensor output based on altitude (Ignition "ON" and engine "OFF")

Altitude Voltage Range
Meters Feet
Below 305 Below 1000 3.8--5.5V
305--610 1000--2000 3.6--5.3V
610--914 2000-3000 3.5--5.1V
914--1219 3000--4000 3.3--5.0V
1219--1524 4000--5000 3.2--4.8V
1524--1829 5000--6000 3.0--4.6V
1829--2133 6000--7000 2.9--4.5V
2133--2438 7000--8000 2.8--4.3V
2438--2743 8000--9000 2.6--4.2V
2743--3048 9000-10000 2.5--4.0V
Low altitude = High Pressure = High Voltage
 
SmithvilleD said:
Been a few years since I've used this data, but the calibration curve on the common GM 1, 2, & 3 bar MAP's are posted on many aftermarket piggyback or standalone ECM forums.

The chart below describes the pressure-to-voltage relationship of the stock GM Turbo MAP sensor (2 bar):
Manifold Pressure
(relative sea level / absolute) 2 Bar
MAP Output
14.31psi / 29.01psi 4.90V
14.00psi / 28.70psi 4.84V
13.00psi / 27.70psi 4.67V
12.00psi / 26.70psi 4.50V
11.00psi / 25.70psi 4.33V
10.00psi / 24.70psi 4.16V
9.00psi / 23.70psi 3.99V
8.00psi / 22.70psi 3.82V
6.00psi / 20.70psi 3.47V
4.00psi / 18.70psi 3.13V
2.00psi / 16.70psi 2.79V
0.00psi / 14.70psi 2.45V
5.00inHg / 12.24psi 2.03V
10.00inHg / 9.78psi 1.61V
15.00inHg / 7.33psi 1.19V
20.00inHg / 4.87psi 0.77V
25.00inHg / 2.41psi 0.35V
29.10inHg / 0.40psi 0.02V

MAP sensor output based on altitude (Ignition "ON" and engine "OFF")

Altitude Voltage Range
Meters Feet
Below 305 Below 1000 3.8--5.5V
305--610 1000--2000 3.6--5.3V
610--914 2000-3000 3.5--5.1V
914--1219 3000--4000 3.3--5.0V
1219--1524 4000--5000 3.2--4.8V
1524--1829 5000--6000 3.0--4.6V
1829--2133 6000--7000 2.9--4.5V
2133--2438 7000--8000 2.8--4.3V
2438--2743 8000--9000 2.6--4.2V
2743--3048 9000-10000 2.5--4.0V
Low altitude = High Pressure = High Voltage
Click to expand...

Perfect, that's what I've been hunting for.

Thanks
 
If ours is only 2 bar then it wouldnt be able to tell me Im going over 15psi boost, but it does. So is it really a 2 bar MAP? Or is it 2 bar over atmospheric, which would be 3 bar I guess.
 
buddy said:
If ours is only 2 bar then it wouldnt be able to tell me Im going over 15psi boost, but it does. So is it really a 2 bar MAP? Or is it 2 bar over atmospheric, which would be 3 bar I guess.
Click to expand...

The stock programming will code if you exceed about 8-9 pounds of boost at sea level for more than about 30 seconds(except for some of the 00 that are said to hold close to 10-11).
 
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