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Thread: 2 Bar MAP Sensor Question

  1. #1
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    Lightbulb 2 Bar MAP Sensor Question

    I have the HP ECU. I'm using the Holley 2 bar MAP sensor and there is a kPa offset option. Can anyone clarify the purpose of the offset? At first glance, I thought this may be used as a way to set atmospheric pressure for sensor calibration reference. However, I see that the ECU has a barometric pressure sensor on the back, which would infer that the pressure sensors are using that as a calibration reference. Thanks.

  2. #2
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    You don't need to use it. It's just there to adjust a MAP sensor that you know is reading a tad off.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  3. #3

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    Curious about this. I've been running a 3 bar GM (2525) and switched to a Holley 2 bar. Key-on the GM MAP sensor read 102, the Holley MAP sensor reads 100. Can I use the Offset to bump up the kPa to 102, or is the 002 difference not worth worrying about? Thanks.

  4. #4
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    Quote Originally Posted by jimbo72 View Post
    Can I use the Offset to bump up the kPa to 102, or is the 002 difference not worth worrying about?
    It's not necessary. The Offset will change the entire MAP sensor scale, not just at WOT.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  5. #5

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    I didn't think of that, thanks Danny!

  6. #6
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    Not that 2 kPa would be a problem (you'd tune it the same way), but I still wouldn't want to replace MAP sensor brands/types on a tuned engine (unless I had to).
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  7. #7

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    Since I haven't started it up with the new sensor, I think it's best I save a copy of the tune with the GM sensor,
    just in case the Holley 2 bar runs differently. The GM sensor got oil soaked from the PCV system (which I since changed).
    And while it worked, I decided to switch to a spare, which was supposed to be a 3 bar Holley, but was a 2 bar.

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