Map rescaling

[Spareparts]

At what point to you need to start to rescale the map sensor or is it even needed

 

[2007 5.9]

Not needed...I've got trucks making over 80psi and no issues.

 

[Spareparts]

thank ya sir

 

[ComnRailPwr]

And reading that pressure off the factory sensor?

 

[2007 5.9]

And reading that pressure off the factory sensor?

No sir...factory is a 3-bar sensor...45psi is its limit.

80 psi was mechanical gauge.

 

[ComnRailPwr]

Thought so.

 

[triton]

No sir...factory is a 3-bar sensor...45psi is its limit.

80 psi was mechanical gauge.

Is 45 really it ? I've got to 58 psi in logs. Not that it helps when I need to see 80+

 

[ComnRailPwr]

47 is all I can get outa mine.

 

[Nitrouskix]

Is 45 really it ? I've got to 58 psi in logs. Not that it helps when I need to see 80+

Does it read 14 psi at idle also? I think you subract 14(atmospheric pressure) so 44psi would be about right for factory sensor. I could be wrong though.

 

[Jpaulbaker]

you are right....there is no "Boost" sensor. The map sensor reads Absolute pressure, the Baro reads just that, Barometric pressure. MAP minus Baro will give you reference Boost. If you are logging the common PIDS that most are, then you have got MAP and not Boost (even though it says CM.BOOST it's actually MAP pressure). To log actual boost, look for this PID

Cummins Actual Boost Pressure {CALC.CMACTBOOST}
Expression:
PSI = {CM.BOOST.psi}-{CM.BARO_B.psi}

It is in a weird PID group if I remember right, and didn't fall into what I was needing to see so I have never logged it.


Of course, i could be wrong about all of this...has been known to happen