Jarrod Power Posted June 10, 2007 Report Share Posted June 10, 2007 I'm looking at replacing factory MAP sensor, and I'm thinking for future tunability I'd put a 5 BAR one in it's place. I'd like to ask about the resolution of the Link MAP sensors. If I only run 1.3 Bar in the short term will the 5bar one lack resolution? Am I better of using off a 2.5 bar one and replace it when/if I rebuild and decide to run more boost later on? Quote Link to comment Share on other sites More sharing options...
ashesman Posted June 10, 2007 Report Share Posted June 10, 2007 All MAP sensors are completely analog which effectively means they have infinite resolution. It is the ECU that causes a loss of resolution. The analog MAP signal is converted to a number inside the ECU. If the ECU has a 8 bit analog to digital converter (ADC) then a 0-5V signal is converted to a number between 0 and 255 (old Link ECU's). If the ECU has a 10 bit (G2/G3 ecu's) ADC then a 0-5V signal is converted to a number between 0 and 1023. Having a more precise ADC is wasted as noise on the signal causes the extra resolution to be wasted.  Also MAP sensors are rated as absolute, so a 2.5 Bar sensor is good for 1.5 bar (14.7 psi) of boost. 1 Bar = 100 kPa. Ok, so here are the resolutions of a few MAP sensors on certain ECU's: 2.5 (14.7 psi boost) Bar MAP Sensor 8 bit ADC - approx 1 kPa.3.0 (29.4 psi boost) Bar MAP Sensor 8 bit ADC - 0.85 kPa5.0 (58.8 psi boost) Bar MAP Sensor 8 bit ADC - approx 2.8 kPa.2.5 Bar MAP Sensor 10 bit ADC - approx 0.25 kPa.3.0 Bar MAP Sensor 10 bit ADC - approx 0.3 kPa.5.0 Bar MAP Sensor 10 bit ADC - approx 0.7 kPa.As you can see, the best resolution comes from the highest precision ADC (such as used in G2/G3 ECU's) and the lowest range possible MAP sensor. If you use a 5 Bar sensor on an old Link ECU which I don't think is even possible, you end up with a bad resolution of 2.8 kPa.In short I can tell you from experience that you should go for the lowest value MAP sensor that will allow you to run enough boost... Quote Link to comment Share on other sites More sharing options...
Jarrod Power Posted June 12, 2007 Author Report Share Posted June 12, 2007 Can I confirm then that a 3 bar Delco MAP sensor is ok with Possumlink for RS Liberty? Quote Link to comment Share on other sites More sharing options...
Simon Posted June 14, 2007 Report Share Posted June 14, 2007 Will need to confirm the firmware you are running. It will be on a sticker on the main micro. It should be something like RSROADq Quote Link to comment Share on other sites More sharing options...
Simon Posted June 14, 2007 Report Share Posted June 14, 2007 In that case the 3 bar delco map will be all sweet. Just remember once you sellect the 3 bar option you need to do a reload and retune. Quote Link to comment Share on other sites More sharing options...
Simon Posted June 26, 2007 Report Share Posted June 26, 2007 You could try http://www.motsons.com.au/ or Dyno Performance U2/ 7 Geonic Crt, Underwood, Brisbane, QLD 4119 Tel +61 +7-3290 5555 Quote Link to comment Share on other sites More sharing options...
Simon Posted June 26, 2007 Report Share Posted June 26, 2007 Or any of the other dealers from our dealer page http://www.linkecu.com/dealers/dealersaustralia Quote Link to comment Share on other sites More sharing options...
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