Exhaust Flaps Issue?

Discussion in 'Dodge Challenger SRT Hellcat' started by 2015_Hellcat, Jul 30, 2015.

  1. 2015_Hellcat

    2015_Hellcat Rookie

    Joined:
    Jul 23, 2015
    Messages:
    12
    Likes Received:
    4
    Trophy Points:
    3
    Vehicle:
    Challenger SRT Hellcat
    I searched the forum and didn't find an answer to a question I have. Should there be an audible difference in the exhaust sound at idle or at slow speeds in Track/ Sport/ Default modes, or only at WOT in Track mode?

    It seems when I first drove the car there would be a noticeable difference while cruising around town in Track mode, but can't notice any differences in various modes. I'm wondering if my flaps are operating properly.
     
  2. B5 Blue

    B5 Blue Platinum Member

    Joined:
    Jan 5, 2015
    Messages:
    6,857
    Likes Received:
    1,742
    Trophy Points:
    1,178
    Location:
    Michigan
    Vehicle:
    Charger SRT Hellcat
    Does it sound the same at 1/2 and full throttle? I run trans in Sport in town and and low rpm it's kinda quiet as it should be until I dip into it.
     
    • Agree Agree x 1
  3. fnkychkn

    fnkychkn swollen member Gold Supporting Member

    Joined:
    Jan 24, 2015
    Messages:
    1,371
    Likes Received:
    486
    Trophy Points:
    368
    Location:
    plastic take-out container
    Vehicle:
    Charger SRT Hellcat
    if they weren't operating properly (not moving where and when commanded by the PCM), the MIL would illuminate and a fault code would set. the only way i can see them working differently than designed would be a software issue or exhaust restriction.
     
    • Agree Agree x 1
  4. B5 Blue

    B5 Blue Platinum Member

    Joined:
    Jan 5, 2015
    Messages:
    6,857
    Likes Received:
    1,742
    Trophy Points:
    1,178
    Location:
    Michigan
    Vehicle:
    Charger SRT Hellcat
    Do they have a potentiometer?
     
  5. fnkychkn

    fnkychkn swollen member Gold Supporting Member

    Joined:
    Jan 24, 2015
    Messages:
    1,371
    Likes Received:
    486
    Trophy Points:
    368
    Location:
    plastic take-out container
    Vehicle:
    Charger SRT Hellcat
    internal hall effect sensor determines valve position.
     
    • Useful Useful x 1
  6. B5 Blue

    B5 Blue Platinum Member

    Joined:
    Jan 5, 2015
    Messages:
    6,857
    Likes Received:
    1,742
    Trophy Points:
    1,178
    Location:
    Michigan
    Vehicle:
    Charger SRT Hellcat
    Even better;) Audi started using those for seat position ans window motors 3 or 4 years ago
     
  7. fnkychkn

    fnkychkn swollen member Gold Supporting Member

    Joined:
    Jan 24, 2015
    Messages:
    1,371
    Likes Received:
    486
    Trophy Points:
    368
    Location:
    plastic take-out container
    Vehicle:
    Charger SRT Hellcat
    from FSM:

    P1217 / P121B ACTIVE EXHAUST VALVE 1/2 PERFORMANCE

    Theory of Operation
    The purpose of the Active Exhaust Valves are to reduce exhaust noise in order to meet pass-by noise regulations. The Active Exhaust Valves consist of two parts. First is the mechanical butterfly valves that are welded into the exhaust pipe on each bank. Mounted to each of these is a smart actuator. They are connected to the mechanical valves through a transmission spring. This is to help reduce heat from transferring between the mechanical butterfly valves and the actuators.

    The Active Exhaust Valve actuators communicate with the Powertrain Control Module (PCM) over a LIN Bus circuit. The Active Exhaust Valve actuator 1 (left) and Active Exhaust Valve actuator 2 (right) each has a unique part number/internal ID. The PCM can identify each actuator location by this unique ID. The PCM sends a position command to the Active Exhaust Valve actuators based on engine torque, rpm and vehicle speed. The Active Exhaust Valve actuators move the butterfly valves to the commanded position. An internal Hall Effect sensor counts the pulses and determines valve position. The valve actuators are calibrated at every Key-ON event. The PCM sends full open and full closed commands and checks actual position against commanded position. If for any reason the calibration is unsuccessful , the actuators are self-diagnosing and report fault flags to the PCM over the LIN Bus.

    If the valve position doesn’t match a predetermined calibration, a performance code is set and the valves will default to the full open position. If an actuator is not attached to the mechanical valve, or the transmission spring is broken or missing, the actuator will continue to rotate indefinitely and set a fault. Also, if the mechanical valve is stuck and will not move, a fault will set.

    NOTE: There is a crossover in the exhaust, upstream of the valves that will allow the exhaust to flow through the open valve in the event one of the valves is stuck closed.

    NOTE: If the transmission spring breaks or the valve becomes disconnected from the actuator for whatever reason the valve assembly likely will cause a rattling noise with the engine running.



    When Monitored and Set Conditions
    When Monitored: This diagnostic runs continuously when the following conditions are met:

    • Engine running longer than 25 seconds.
    • Engine running above 500 rpm.
    • Coolant temperature above 25°C (77°F).
    • No Active Exhaust Valve 1/2 Actuator communication faults.
    • Valve calibration completed.


    Set Conditions:

    • The actual Active Exhaust Valve 1/2 Actuator position does not match the commanded position.


    Default Actions:

    • The MIL light will illuminate.



    Possible Causes
    MECHANICAL BUTTERFLY VALVE SEIZED
    TRANSMISSION SPRING BROKEN
    ACTIVE EXHAUST VALVE 1/2 ACTUATOR
     
    • Useful Useful x 4
  8. B5 Blue

    B5 Blue Platinum Member

    Joined:
    Jan 5, 2015
    Messages:
    6,857
    Likes Received:
    1,742
    Trophy Points:
    1,178
    Location:
    Michigan
    Vehicle:
    Charger SRT Hellcat
    All info added to my notes fnkychkn thanx
     
  9. ljaviation

    ljaviation Self proclaimed Banned, Because I can.

    Joined:
    Feb 10, 2015
    Messages:
    644
    Likes Received:
    244
    Trophy Points:
    193
    Location:
    Asheboro, NC
    Vehicle:
    Challenger SRT Hellcat
    Great info fnkychkn.
     
  10. solo7777

    solo7777 SRT Terminator Hellcat Car Club Western Regional President HCC Charter Member

    Joined:
    Nov 25, 2014
    Messages:
    3,038
    Likes Received:
    1,368
    Trophy Points:
    768
    Location:
    City Of The Angels
    Vehicle:
    Challenger SRT Hellcat
    Try this, go slow at idle, then floor it. If you can't tell the difference, then get some ear cleaner!:D
     
    • Funny Funny x 1
  11. Hugh Jorgan

    Hugh Jorgan Silver Member

    Joined:
    Oct 27, 2014
    Messages:
    456
    Likes Received:
    123
    Trophy Points:
    153
    Vehicle:
    Challenger SRT Hellcat
    So if I understand correctly, these thingd are simply electronically controlled butterflies that look like the old heat riser valves? If so, all they would seem to do is create backpressure.
     
    • Winner Winner x 1
  12. soundman5000

    soundman5000 Silver Member

    Joined:
    Jun 25, 2015
    Messages:
    531
    Likes Received:
    121
    Trophy Points:
    153
    Location:
    Murrells Inlet, South Carolina
    Vehicle:
    Challenger SRT Hellcat
    It may be my imagination but I hear a difference when I change the SRT pages from default to track while driving. Both are 707 HP so why would I hear it get louder as it looks like it just softens up suspension and turns traction on or off but Im thinking when set to track it opens the exhaust up? I hear it when I change at highway speed say 45 to 55 mph. Try it and report back...
    Anyone else?
    [​IMG]
     
    Last edited: Aug 1, 2015
  13. usmc341

    usmc341 Gold Member

    Joined:
    May 27, 2015
    Messages:
    1,448
    Likes Received:
    407
    Trophy Points:
    218
    Location:
    Henderson, NV
    Vehicle:
    Challenger SRT Hellcat
    I believe track mode keeps the butterflies full open
     
    • Agree Agree x 1

Share This Page

Search tags for this page

active exhaust rattling from flaps

,

charger hellcat active exhaust system

,

dodge challenger hellcat active exhaust makes weird sound when open and close

,

keep exhaust flaps open on challenger

,

srt sport flaps