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Thread: "The" DPF removal write-up

  1. #1
    Lifetime Member Boost's Avatar
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    Default "The" DPF removal write-up --> warning: this may be illegal, even for offroad use

    I'd like to gather all the useful info in one place about DPF removal.

    DISCLAIMER:

    The DPF was designed to allow the Duramax to comply with the extremely strict new diesel emissions regulations.
    Removing or modifying it is illegal in the US (even for offroad use)!


    Now on to the good stuff:

    For those that use their LMM for racing only and off-road, removing the DPF has shown substantial gains in fuel economy and power. However, it will cause serious complications. In this thread I hope to gather ALL of the correct information for people who decide to modify their LMM exhaust for whatever reason.
    Last edited by joecar; January 30th, 2013 at 07:14 PM. Reason: Added off-road disclaimer in the title also
    TORQUE SOUTH Tuning 125 VINs programmed
    2013 Buick Verano T 400+ lb-ft tq @ 26 psi with EFILive E39A
    1/8 mile: 8.933 @ 78.6 mph - world's fastest GM Delta platform
    2012 Chevy Cruze LTZ RS 200+ lb-ft torque @ 22 psi with EFILive E78 / T76
    40,000 MILES SO FAR OF RELIABLE AND POWERFUL 30 MPG TUNE
    www.torquesouth.com / www.gmtune.com / www.tstune.com

  2. #2
    Lifetime Member Boost's Avatar
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    Last edited by Boost; December 24th, 2007 at 09:01 AM.
    TORQUE SOUTH Tuning 125 VINs programmed
    2013 Buick Verano T 400+ lb-ft tq @ 26 psi with EFILive E39A
    1/8 mile: 8.933 @ 78.6 mph - world's fastest GM Delta platform
    2012 Chevy Cruze LTZ RS 200+ lb-ft torque @ 22 psi with EFILive E78 / T76
    40,000 MILES SO FAR OF RELIABLE AND POWERFUL 30 MPG TUNE
    www.torquesouth.com / www.gmtune.com / www.tstune.com

  3. #3
    Lifetime Member Boost's Avatar
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    These are the codes that are related to / set because of DPF removal:

    P2459 - Regeneration too often
    P244C - Catalyst temperature too low during regeneration
    P244B - DPF differential pressure too high
    P2463 - Diesel particulate filter soot level accumulation
    Last edited by Boost; November 4th, 2007 at 02:30 AM.
    TORQUE SOUTH Tuning 125 VINs programmed
    2013 Buick Verano T 400+ lb-ft tq @ 26 psi with EFILive E39A
    1/8 mile: 8.933 @ 78.6 mph - world's fastest GM Delta platform
    2012 Chevy Cruze LTZ RS 200+ lb-ft torque @ 22 psi with EFILive E78 / T76
    40,000 MILES SO FAR OF RELIABLE AND POWERFUL 30 MPG TUNE
    www.torquesouth.com / www.gmtune.com / www.tstune.com

  4. #4
    Lifetime Member Boost's Avatar
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    Here is an overview of the DPF system:

    The DPF system has 2 components - the DOC and the DPF. The DOC (Diesel Oxydation Catalyst) comes before the DPF and has been used on diesel engines for years. It's pretty much a regular cat. The DPF (Diesel Particulate Filter) captures diesel exhaust gas particulates (soot) to prevent their release into the atmosphere. It forces particulate-laden exhaust through porous cell which has silicon carbide substrate with honeycomb cell-type channels. It's channels are wash-coated with catalyst materials like those in DOC. The DPF is a "wall-flow" type filter. The soot that accumulates turns into residual ash after regeneration. There are two EGT sensors, one before and one after the DPF. The ECM monitors signals from EGT sensors to control DPF regeneration. The ECM supplies biased 5-volts to signal circuit and ground on low reference circuit to EGT Sensor 1. When EGT Sensor 1 is cold, resistance is high. As temperature increases, sensor resistance decreases. The ECM detects high or low sensor resistance voltage on signal circuit.
    Proper exhaust gas temperatures at DPF inlet are crucial for proper operation and initiating regeneration. The DPF substrate melts / cracks if temperature is too high. Regeneration is terminated at temperatures above 800°C (1472°F). Self-regeneration will not fully complete soot-burning process if temperature is too low. There is also a Differential Pressure sensor with sample lines before and after the DPF. Calculations from this sensor are extremely important for DPF operation. Excessive fuel useage, loss of power, and possible engine damage can result from too much back pressure caused by a clogged DPF. The ECM will start a regeneration to clear this filter based on distance, fuel, and engine run time since last DPF regeneration, and exhaust differential pressure across the DPF. The computer can actually calculate how many grams of soot are in the filter based on info from all the sensors. Several engine components assist regeneration (engine speed, fuel pressure are adjusted). Late post-injection pulses provide the engine with additional fuel which increases exhaust temperatures entering the DPF to 500°C (932°F) and higher. Contribution to exhaust heat from late post injections is approximately 45%. The intake air valve acts as restrictor to reduce air entry into engine. Engine operating temperature increases by approximately 35%. The intake air heater can also help during regeneration. The turbocharger also plays role in achieving regeneration temperatures by reducing or increasing boost depending on engine load. It's contribution to increasing engine heat is about 10%. The are two main types of regeneration: Passive and Active. Passive regeneration may occur during normal vehicle operation when driving conditions produce sufficient load and exhaust temperatures, without input from ECM or driver (typically while vehicle is being driven at highway speed or towing a trailer). Active regeneration is commanded by ECM when the DPF requires excess soot build up to be removed and conditions for regeneration have been met. It's ususally hard to detect. The truck needs to be driven at speeds above 30 mph for approximately 20-30 minutes for a full regeneration to complete. During this time, exhaust gases reach temperatures above 550°C (1022°F). If regeneration is interrupted, it will continue where it left off (including the next drive cycle) when the conditions are met for regeneration. When regeneration is required, but the vehicle’s operating conditions do not meet the ECM’s requirements (such as frequent short trips or extended idling, the ECM turns on a “Clean Exhaust Filter” indicator. This message appears when the ECM determines soot levels are over 125%, and it remains on DIC display until after regeneration has been completed. Active regeneration has two stages. The first stage warms up DOC by reducing airflow using air intake valve, adjusting turbo boost and fuel rail presuure, and adding late fuel injection pulses. In the second stage the DPF is heated to temperature required to incinerate particulate matter. If a customer requested active regeneration is interrupted, the process ends and will not be activated again until conditions are suitable for regeneration or the regeneration switch is pressed again. An unknown amount of soot can be present resulting from engine or engine control errors caused by a charge air cooler leak, or low compression. If there is over 100 grams of soot, regen is not permitted. One trick is to unplug the sample lines of the differential sensor and force regen.
    Last edited by Boost; November 4th, 2007 at 02:28 AM.
    TORQUE SOUTH Tuning 125 VINs programmed
    2013 Buick Verano T 400+ lb-ft tq @ 26 psi with EFILive E39A
    1/8 mile: 8.933 @ 78.6 mph - world's fastest GM Delta platform
    2012 Chevy Cruze LTZ RS 200+ lb-ft torque @ 22 psi with EFILive E78 / T76
    40,000 MILES SO FAR OF RELIABLE AND POWERFUL 30 MPG TUNE
    www.torquesouth.com / www.gmtune.com / www.tstune.com

  5. #5
    Lifetime Member Boost's Avatar
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    These are the parameters that have to be altered for DPF removal:

    Change B2501 to No
    Change B2502 to 0
    Set the regen min engine temp to the max value (ie: higher than opperating temps)
    Last edited by Boost; November 4th, 2007 at 01:33 AM.
    TORQUE SOUTH Tuning 125 VINs programmed
    2013 Buick Verano T 400+ lb-ft tq @ 26 psi with EFILive E39A
    1/8 mile: 8.933 @ 78.6 mph - world's fastest GM Delta platform
    2012 Chevy Cruze LTZ RS 200+ lb-ft torque @ 22 psi with EFILive E78 / T76
    40,000 MILES SO FAR OF RELIABLE AND POWERFUL 30 MPG TUNE
    www.torquesouth.com / www.gmtune.com / www.tstune.com

  6. #6
    Lifetime Member Boost's Avatar
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    Since this forum has the benefit of editing with no time limit, I will keep updating my above posts to keep all the info at the top in one place. Please feel free to chime in. Thanks!
    Last edited by Boost; November 4th, 2007 at 02:32 AM.
    TORQUE SOUTH Tuning 125 VINs programmed
    2013 Buick Verano T 400+ lb-ft tq @ 26 psi with EFILive E39A
    1/8 mile: 8.933 @ 78.6 mph - world's fastest GM Delta platform
    2012 Chevy Cruze LTZ RS 200+ lb-ft torque @ 22 psi with EFILive E78 / T76
    40,000 MILES SO FAR OF RELIABLE AND POWERFUL 30 MPG TUNE
    www.torquesouth.com / www.gmtune.com / www.tstune.com

  7. #7
    Forum tyhee Site Admin GMPX's Avatar
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    Thanks for the assistance on this one.
    Would be good to get feedback from everyone on how this is going too.

    Cheers,
    Ross
    Before asking for help, please read this.
    Need official EFILive help, please go here.
    For tuning support please post your questions on this forum (or other auto forums).
    Sorry if I don't respond to your PM, don't take it personal.

    In The Garage:
    2014 Holden Cruze 2.0L Diesel, A6 (E20 ECM), 430Nm @2,500, (Highway 4.5L/100km : 52MPG), sweet!
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    Who, who, who, who, who?.
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    (old school Prius).
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  8. #8
    Lifetime Member IdahoRob's Avatar
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    No problems on the latest LMM DPF removed here.
    2007 5.9 Cummins 3500
    2007.5 6.7 Cummins 2500 new test mule

    2002 LB7, 4x4 (Max'd Out) 6000lbs
    9.36 @ 149 mph 2011 NHRDA Champion and Record holder

    All EFI tuned by Adrenaline Truck Performance

  9. #9
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    Been DPF Free since the end of august no problems at all to date.

  10. #10

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    Boost,

    Been out of the diesel scene for a bit but this is some good info. I'll be following this thread.

    Howard

    www.redline-motorsports.net

    1-954-703-5560

    2006 ZO6 895/866 with APS TT
    2010 SSRS Camaro HTR-900TT (798/801)
    2011 HTR-850R Camaro
    2012 ZL1 Auto (10.33@135 MPH) Video Here!

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