2.0L LNF Performance Tech 260hp and 260 lb-ft of torque Turbocharged tuner version.

34.8 PSI in MAP

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Old 06-22-2016 | 04:59 PM
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katriik's Avatar
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34.8 PSI in MAP

Hello everyone.
So I decided to try a WOT at third and fourth gear to check the current pressure I can get from a recently purchased Cobalt SS 2010.
The MAP sensor got stable at 249 kpa (34.8 PSI) several times.
I realized that the MAP sensor is the one found with GM stage 1 option.
I would like to check with you if that is a normal value or if I need to further investigate if the previous owner did other things to the engine.
Thanks a lot.
Old 06-22-2016 | 05:09 PM
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You are likely not logging correctly and that really means you are running a 20psi tune.
Old 06-22-2016 | 05:14 PM
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So when I read the pressures on the forum, they are boost only, not map, correct? Because the boost gauge on the car shows 140 kpa (as you said: 20 psi).
Old 06-22-2016 | 05:49 PM
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If you're reading off the MAP sensor in hptuners, you have the wrong sensor and it will peg at 249kPa. You need to log the lo res map, which is the sensor in the charge pipe. Again both are absolute pressure not a gauge pressure above atmosphere so the baro reading needs to be subtracted to get to boost
Old 06-22-2016 | 06:52 PM
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Originally Posted by ECaulk
If you're reading off the MAP sensor in hptuners, you have the wrong sensor and it will peg at 249kPa. You need to log the lo res map, which is the sensor in the charge pipe. Again both are absolute pressure not a gauge pressure above atmosphere so the baro reading needs to be subtracted to get to boost
The reading is from Torque-BHP... Android app, very basic. I am new to this world so I'm trying to learn everything I can.
I saw there are two pressure sensors on the car, one fixed on the manifold intake and the other from the charge pipe. The app says Intake Manifold Pressure.
Any ideas on how to be sure? Just by disconnecting?
Old 06-22-2016 | 07:55 PM
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I don't know anything about those apps to help.

Sorry.

Just subtract 14.7 and you have your reading.


Your boost gauge is accurate though. It's probably a GMS1 factory tune.
Old 06-22-2016 | 08:04 PM
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I know nothing about that app. I'd put anything that logs pressure and see the differences and compare to the gauge
Old 06-22-2016 | 08:10 PM
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34.8-14.4 = 20.4. Ur running 20 psi
Old 06-22-2016 | 10:28 PM
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Two points, first I incorrectly stated that the map pegs at 249kpa when it's actually 255kpa.

Also 249kpa is actually 36.1psi. So OP's actually running a 22psi tune, and needs to log the charge pipe map
Old 06-23-2016 | 12:28 PM
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Originally Posted by katriik
The reading is from Torque-BHP... Android app, very basic. I am new to this world so I'm trying to learn everything I can.
I saw there are two pressure sensors on the car, one fixed on the manifold intake and the other from the charge pipe. The app says Intake Manifold Pressure.
Any ideas on how to be sure? Just by disconnecting?
I am almost 100% sure the app is reading the intake manifold sensor. My app was (app that comes with OBDlink MX). Which is capped at 255kpa as was previuosly stated (22.5 psi gauge). Even with the GMS1 3 bar sensors in place, the PCM will only report a max value of 255kpa (even though the sensor goes much higher).

You seam to be just under that, so it is probably reading correctly. But beware that if the app boost flatlines at 255kpa, it could be higher in reality.

HP tuners is by default just going to read that same sensor that has a PCM cap of 255 (intake manifold sensor). You have to setup a PID for Boostlo-res which is not capped by the PCM and will read and report up to the max of the sensor itself (3 bar if you have the GMS1 sensors).
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