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Thread: Logging Boost---should it be negative????

  1. #1
    Advanced Tuner coachcrow56's Avatar
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    Logging Boost---should it be negative????

    I made an attempt at logging Boost on my 2000 GTP, but I am getting negative readings driving around town and a positive reading of 7+ under hard acceleration. I am attaching a scan, and my scan config.

    My Math Parameter setup is Manifold Absolute Pressure 50030.98 - Barometric Pressure 50032.98.

    Would someone with more experience than me take a look and see if I set it up right?

    I am using Barometric pressure and MAP to create my Boost graph.
    Attached Files Attached Files
    Last edited by coachcrow56; 05-08-2020 at 02:09 PM.
    2.8/3.0/3.2 Pulley/ZZP CAI/1.6 HS Rockers/Hi Energy Comp Cam 76-802-9/LS7 Lifters/ZZP Stage 2 Intercooler/TOG Headers/Triple Edge Performance Stage 3 Transmission/3.29 Ratio/NGK TR6ix IRIDIUM .40 GAP/ZZP Fuel Rails/ZEX 100 shot NOS/GMPP Sway Bars/KYB Adjustable Struts/Power Stop Performance Pads/Rotors

  2. #2
    Advanced Tuner coachcrow56's Avatar
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    Come on guys---there has to be one person out there who can confirm that I am either right or wrong-----one person----I know there are tuners out there that log boost----come on!!

    I fixed my formula and got the following results on 3 different pulleys.

    2.8 pulley 10.03 psi Boost
    3.0 pulley 8.63 psi Boost
    3.2 pulley 7.41 psi Boost
    Last edited by coachcrow56; 06-29-2020 at 06:16 PM.
    2.8/3.0/3.2 Pulley/ZZP CAI/1.6 HS Rockers/Hi Energy Comp Cam 76-802-9/LS7 Lifters/ZZP Stage 2 Intercooler/TOG Headers/Triple Edge Performance Stage 3 Transmission/3.29 Ratio/NGK TR6ix IRIDIUM .40 GAP/ZZP Fuel Rails/ZEX 100 shot NOS/GMPP Sway Bars/KYB Adjustable Struts/Power Stop Performance Pads/Rotors

  3. #3
    Tuner in Training
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    Bump

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    Its normal...
    Daily Driver= 2003 BMW 330xi
    Weekend Cruiser= 2009 Pontiac G8 GT (Vararam, TSP LS3 N/A Stage 1, OBX, CTS-V converter, MagnaFlows w/ J-Pipes, 160 t-stat)
    Project Car= 1991 Chevrolet Camaro RS (LQ4 w/ Gen 4 Rods, LS3 heads, turbo...)
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  5. #5
    Advanced Tuner coachcrow56's Avatar
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    Thanks
    2.8/3.0/3.2 Pulley/ZZP CAI/1.6 HS Rockers/Hi Energy Comp Cam 76-802-9/LS7 Lifters/ZZP Stage 2 Intercooler/TOG Headers/Triple Edge Performance Stage 3 Transmission/3.29 Ratio/NGK TR6ix IRIDIUM .40 GAP/ZZP Fuel Rails/ZEX 100 shot NOS/GMPP Sway Bars/KYB Adjustable Struts/Power Stop Performance Pads/Rotors

  6. #6
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    Quote Originally Posted by coachcrow56 View Post
    Thanks
    No problem. I would log KPA so that it will be less confusing. Or use the built in boost math that doesnt show negative boost (manifold vacuum) in PSI.
    Daily Driver= 2003 BMW 330xi
    Weekend Cruiser= 2009 Pontiac G8 GT (Vararam, TSP LS3 N/A Stage 1, OBX, CTS-V converter, MagnaFlows w/ J-Pipes, 160 t-stat)
    Project Car= 1991 Chevrolet Camaro RS (LQ4 w/ Gen 4 Rods, LS3 heads, turbo...)
    Truck= 2007 Chevy Silverado 1500 LT LY5 4x4

  7. #7
    Tuner in Training
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    I noticed something with my sensor configuration that made be have to stop using the formula that you posted. I could be driving and showing an ambient baro of 13.9 and then give it some gas and the ambient baro would climb to 15.9. So to avoid doing a lot of breakout wiring i have just started using a constant for the barometric pressure. With the sensor getting its data from the MAF, is this suggesting an issue with my MAF sensor?