Daniel Sabler Posted June 20, 2013 Report Share Posted June 20, 2013 Hi,I´m using an AEM 3.5bar Map Sensor in a Skyline R34 GTT (G4 Plug in). The correct AEM constructions are beginning: Volt    PSI 0.5    -14.7 0.75  -11.575 1         -8.5 ....and so on. But in the calibration table I´ve set: Input Units = Volts Output Units = PSI Output Table Start = 0 PSI (the Problem!) Output Table Increments = 2 -- The problem: how can I set the 'vacuum / negative PSI' like -14.7 at 0.5 Volt? The software only allows to start with 0 - not with any vacuum / negative PSI... Quote Link to comment Share on other sites More sharing options...
Steve1436215419 Posted June 20, 2013 Report Share Posted June 20, 2013 Im using KPA on my car but that doesnt matter i assume. I use that sensor to. My calibration table starts at 0 to and ends at 345 kpa. 0 is really 100 kpa vacum so 100 kpa is actually atmospheric pressure. In your case 0 psi is 14.7 psi of vacum and 14.7 is atmosphere. We are dealing with absolute pressure here not gauge pressure. Quote Link to comment Share on other sites More sharing options...
Simon Posted June 20, 2013 Report Share Posted June 20, 2013 You will be better to scale the sensor in kpa as the rest of the software is geared to be in metric readings. Most sensor are linear in there output so you shouldn't need a cal table. Just use a point A point B cal. Quote Link to comment Share on other sites More sharing options...
chris164935 Posted November 27, 2014 Report Share Posted November 27, 2014 Bumping this thread. Â I have an AEM MAP sensor as well, using the point A/point B cal setup, will I be able to see vac readings on my digital display or will it just read 0 and I have to do the math in my head? Â And if my display says I am pushing 20 psi, it is actually 5.3 psi absolute (20-14.7)? Quote Link to comment Share on other sites More sharing options...
Simon Posted November 28, 2014 Report Share Posted November 28, 2014 The Cal will be in absolute. so 0kpa = 100% vacuum 100kpa is roughly atmosphere 200kpa = 1bar or 15psi Attached is a image of a correct cal Quote Link to comment Share on other sites More sharing options...
chris164935 Posted November 30, 2014 Report Share Posted November 30, 2014 Awesome. Â Thanks for the help and fast response! Quote Link to comment Share on other sites More sharing options...
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