Map sensor 2bar - 3 bar resolution values. over boost question.

  • #1

    Map sensor 2bar - 3 bar resolution values. over boost question.

    So previously i ran a GM 2 bar map sensor on the Z as i was running under 10 psi of boost. Well its time to reinstall the system, and my map sensor is missing. so time to buy a new one, this time i am planning to run right a 15-18 psi boost. 2 Bar map sensors are designed up to 15 psi but many have been pressure tested to exceed 50psi according to specs. Has anyone here ran boost a few psi over "said" limits for map sensors? I am thinking the voltage will peak at ~15 psi and anything over wont be read. have any recommendations on a brand? just used generic cheapo last time.

    The reasoning. Price wise they cost is within $20 for a decent map sensor but the significant difference is in the resolution values the 2 bar general values about .9375 in. hg/location with a slightly faster response time, and the 3 bar 1.406 in. hg/location with a slightly slower response time. Though not a huge difference, according to my book i can have an additional 4-6 load points for tuning by staying with 2 bar.

    Any hands on experience here?
  • #2
    I use the "3" bar one with Megasquirt, which is really a 2.5 bar one, the MPX4250. It's not a big deal, the reduced resolution. At least not for the VG30E. If you look a the spec sheets, it will list the voltages it outputs (http://www.freescale.com/files/senso…et/MPX4250.pdf). It looks like it works to about 260-270 kPa. After that you hit the 5v ceiling, which is bad. Perhaps the sensor reads past that but I know Megasquirt limits it, so either way you'd be screwed.
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  • #3
    That's exactly what i was afraid of. I wasn't so concerned with the resolution/response time, just thought it would be nice to have the points on the system to tune. The Manual shows it accepts up to 7 volts but likely that is just over voltage protection, was hoping that this might be utilized for slightly running over the 14.5-15psi rating I've been finding.