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C7 Corvette Exhaust note and Active Fuel Management

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    • February 9, 2013 at 9:15 am #38366
      dutch
      Participant

      How does corvette control the sounds in the exhaust when it goes from 8 to 4 and back up without making the driver wish
      for a stright 8 exhaust? My silverado can not use an after market exhaust because of this 8 to 4 when cruising.

    • February 9, 2013 at 3:37 pm #41064
      Alex Luft
      Keymaster

      Good question, @dutch. I haven’t thought about this myself and don’t have that much experience with AFM. How does AFM impact the exhaust?

    • February 10, 2013 at 7:33 am #41067
      dutch
      Participant

      I have had Silverados that I put an after market exhaust on and if you were out driving and not in town the motor would go up and down in the RPM range. take you radio and sit next to it and turn it up and wait 30sec and turn it down then wait 15sec and turn it up again. think of this as if you were driving. the new vette has the same 8 to 4 with a louder exhaust so how do they control the exhaust note when cruising so it doesn’t drive a person nuts?

    • February 11, 2013 at 8:34 pm #41075
      Alex Luft
      Keymaster

      @dutch does this “problem” only apply to vehicles with AFM equipped with aftermarket exhaust systems?

    • February 12, 2013 at 9:01 am #41077
      dutch
      Participant

      I wouldn’t say it’s a problem but I wouldn’t change the exhaust on my Silverado for an after market exhaust and was just wondering how Chevy over came the changes in exhaust notes with the new Corvette. The one sound clip that was on this site sounded pretty good and I was just wondering

    • February 12, 2013 at 8:41 pm #41083
      Alex Luft
      Keymaster

      Got it. To tell you the truth, I’ve no idea if this was something GM had in mind when designing the exhaust or any car with cylinder deactivation/AFM, C7 included. I guess we’ll have to see once we get closer to launch… maybe this guy knows:
      http://gmauthority.com/blog/2013/02/accident-watch-the-first-known-corvette-stingray-crash/

      🙂

    • February 12, 2013 at 10:44 pm #41084
      dutch
      Participant

      You won’t notice the 8 to 4 and 4 to 8 in the stock system because it is quiet. Put a set of flow master 40’s on and you will definately hear it.

    • February 18, 2013 at 12:09 pm #41095
      EJD
      Participant

      They have integrated sound control valves in the exhaust system just ahead of the mufflers on each side. They are supposed to modulate the sound in four cylinder mode to make it more pleasing to the ear. How affective they will be is probably subjective, and will cause more controversy on the forums.

      These are not to be confused with the valves in the muffler outlets that come with the dual mode NPP exhaust option. With NPP you will actually have four valves; two before the mufflers and two after the mufflers. All are now electric as opposed to the vacuum operated valves used with the previous NPP option.

      I’ve attached a photo to show the location of the valves.
      Ed

    • February 18, 2013 at 9:19 pm #41097
      dutch
      Participant

      thanks that was the kind of info I was looking for

    • February 19, 2013 at 11:41 pm #41099
      Alex Luft
      Keymaster

      @EJD that’s some good stuff. Thanks for sharing the expertise!

      If you click on the photo, it will expand.

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