Active Exhaust mode?

Discussion in 'Dodge Charger SRT 392' started by ufoldfirst, Jul 2, 2015.

  1. ufoldfirst

    ufoldfirst Hellcat Member

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    Other than cold start and track mode, is there a way to have the active exhaust in the open mode when in track or custom mode?
    I would drive in track mode more, but the suspension is too stiff on some of my roads. I would like to have it louder in sport or custom mode!

    I did search the forums and could only find folks trying out aftermarket stuff.
     
  2. Misterdhdt

    Misterdhdt Gold Member

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    There is a topic in the forum on it. I'm doing resonator deletes right now.
    A few of my buddy's did the muffler delete and left the resonators on there challengers. Extremely loud when go fast pedal is mashed.
     
  3. Teo

    Teo Judge Yooper

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    The active exhaust is directly tied to throttle position. The more throttle that is added, the more the exhaust valves open until you are at WOT which the valves are wide-open for straight thru to the res's. Taking off the active exhaust valves may/probaly will throw a check eng lite due to the electronic tie-in. Do a axle back after the valves with 3" straight pipes and it will get much louder with WOT. The problem though is loss of low end torque when doing this. :( The SRT engineers truly have this ride set-up correctly! I would just give it time and miles(approx. 5000miles) to experience the full benefit of their oem design! :D
     
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  4. SRT HC

    SRT HC BANNED

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    What about an axle back that has a little better flowing/sounding resonators? I wish Mopar offered as a performance accessory. I don't really have confidence that an aftermarket exhaust company has the expertise to complement the Hellcat exhaust flow
     
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  5. soundman5000

    soundman5000 Silver Member

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    Do you think Mopar will offer more aftermarket stuff in the future for the Hellcat. I purchased a Mopar CAI and cat back exhaust for my 2012 Ram 1500 and loved it!
    I prefer as much blue Mopar stuff as possible and I would not trust non-Mopar aftermarket exhaust on my cat.
     
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  6. Teo

    Teo Judge Yooper

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    There more than few out there.:oops: But my attitude is WHY spend the money when it is close to perfection already?:rolleyes: The problem is we don't know for sure with any of them UNTIL it gets on the dyno to prove them out! o_O Plus until the motors can be fully re-tuned - SAFELY, why waste those dollars chasing What If's?? :confused:

    Bottom Line: Different Strokes for Different Folks.:cool: I have been there and spent many! $$$ only to fully learn the truth after extensive testing on my own! :mad:

    As I stated, SRT Engineers TRULY have their act together to produce a powerful - quality product with not only longevity in mind, but a balance with the current CARB/EPA rules and regs that are placed upon them. For me and me only, Now I buy it to enjoy it! If it breaks??? ----- Simply let FCA fix it! :D
     
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  7. SRT HC

    SRT HC BANNED

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    What I would like is a little better exhaust note on my Hellcat.without losing any performance.

    Right now when my Hellcat is idling beside my 2005 Magnum, you wouldn't know my Hellcat was running.

    2005 Magnum motor/exhaust specs:
    • 419 cu.in (6.1L based stroker)
    • 228/230 lsa 114 Crower cam
    • Kooks long tube headers
    • catless mid pipes
    • JBA 3" x-pipe
    • Thrush mufflers (Flowmaster 40-like)
    • 3" aluminized steel pipes
    • Hooker resonator tips
     
  8. Teo

    Teo Judge Yooper

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    Key words are catless mid pipes, long tube headers,thrush mufflers!! :cool::cool::cool::cool::cool::cool:
     
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  9. MaxxMuscle

    MaxxMuscle Gold Member Hellcat Car Club HCC Charter Member

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    Give me a schooling Teo.Why would going with 3 inch straight pipes give u lower end tq loss ?
     
  10. SRT HC

    SRT HC BANNED

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    IMO the explanation would be that the lower gas volume of the lower rpm's reduces the scavenging velocity because of the greater pipe diameter. But as the gas cools it decreases in volume anyway. I would think the critical area pretty much ends at the outlet of the muffler. From muffler on back is of little consequence. (of course, this doesn't include adding a smaller pipe to add more restriction after the muffler)
    Disclaimer: Just my thoughts
     
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  11. MaxxMuscle

    MaxxMuscle Gold Member Hellcat Car Club HCC Charter Member

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    Thanks SRT HC .
     
  12. Teo

    Teo Judge Yooper

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    Changing the designed restriction(going to a larger dia. exhaust) may ADD horsepower but decreases restriction/backpressure flow. MAX Intake airflow to any engine must be carefully balanced/ tuned for exhaust pulse width modulation for the out-flow restriction(back pressure) to maintain low end torque.

    Old article, but informative. 2 1 4 inch exhaust or 3-Inch Exhaust - Car Craft Magazine
     
    Last edited: Aug 13, 2015
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  13. SRT HC

    SRT HC BANNED

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    Exhaust backpressure is a misconception for optimizing low end performance. Backpressure is never a good thing.

    What we are trying to optimize can be equated to NASCAR drafting. Exhaust makes pulses for every cylinder that expels its gas. Behind each pulse is a small vacuum that helps pull the next cylinder's expelled gas..So it's exhaust velocity that is of concern.

    At low rpm's the quantity of gas is high, so we want the exhaust piping large enough so as not to restrict the flow, thus lowering the exhaust velocity. But at low rpm's the quantity of gas is lower, and because v = Q/A, the velocity will likewise decrease. When the velocity decreases to the point that the vacuum behind the cylinder exhaust pulse drops such that it has little pull o the next pulse, power is lower.

    So we must chose a pipe diameter that benefits the full range of rpm's, or from a dyno graph perspective, produce the greatest area under the curve.

    IMO, the Hellcat has more than enough torque to worry much about a loss in torque. Just put you Hellcat in track mode and do some sporty driving and see how easy those tires lose traction. Now more high rpm power, where traction is not an issue, that's what I want.
     
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  14. turbolou

    turbolou Senior Hellcat Member

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    Explain to me how exhaust scavenging matters on a boosted engine. Pressure behind the valves covers a lot of sins in fact the less back pressure the better. The principles stated here would make more sense on a N.A engine.
     
  15. MABBRYFL30

    MABBRYFL30 NYS President Hellcat Car Club Gold Supporting Member

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    Why you are taking about really comes down to people having and wanting a louder car.
    The m6 is a touch louder than the a8 exhaust also
     

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