DPF Requirements Exhaust Back Pressure for US2010 and GHG2017 Engines If modifications are made to the exhaust system after the SCR muffler, the back pressure must be measured to ensure the changes do not exceed the back pressure limits. Note: If the pressure in the exhaust is too high, engine damage can result. Requirement: Allowed pressure in the exhaust piping after the SCR muffler; on MP7, MP8 and MP10 engines 3 - 5 kPa (0.43 - 0.73 psi). Note: To view back pressure accurately use VCADS procedure 2545-08-03-02, Exhaust Aftertreatment Diagnostics. Note: The maximum allowed added back pressure from exhaust piping is 4 kPa (0.6 PSI). Measuring Back pressure:
1 Remove the post NOx sensor and add a pressure gauge (Thread size - M20 x 1.5). 2 With the gauge attached to the exhaust pipe, run the engine at High Idle (2000 rpm with no engine load) for 3-5 minutes. Note: The test should be conducted with the vehicle between 60 - 70 °F (16 - 21 °C). 3 Record the exhaust pressure at the end of the 3-5 minute period. Notes Mack Body Builder Instructions PI / CHU, AN / CXU, GR / GU, TD, LR, TE / MRU USA141023213 Date 2.2018 Body Builder; Engine, MP7, MP8, and MP10 Page 26 (40) All Rights Reserved