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Wondering about Exhaust

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by ecker_97, Jan 2, 2012.

  1. ecker_97

    ecker_97 New Member

    I have a 2008 Silverado with the engine that switches over from V8 mode to V4 mode, I am thinking about putting a cat-back exhaust on it and wondering if it will sound alright or weird when it goes into the V4 mode? And also wondering what a good exhaust would be?
  2. tbplus10

    tbplus10 Super Moderator Staff Member Platinum Contributor 1000 Posts

    I've been doing a lot of research on this subject since I have a 2011 with AFM that I'd like a little louder.
    Some of my findings are as follows:
    V-4 to V-8 sound wont be a real issue since normally your doing 60mph before it ever kicks over to V-4, who can really hear your exhaust at that speed?
    After getting a new exhaust you will need to get a tune, the engine and system wont like the new free flowing exhaust and will cause issues.
    Without the back pressure it may have a hard time switching to V-4 which may cause degraded fuel mileage.
    You can have the AFM system turned off, at this time theres no real stats if this will degrade performance or Fuel mileage.
    And if you make any changes to the computer system they are logged, no one can definately say if this will assist a dealer in voiding your warranty.
    GM does make performance exhaust systems, I havent gotten a good answer from their reps yet if these systems are compatable with AFM systems and if theirs computer changes required, and if the dealer completed these changes would they stay with-in warranty guidlines, hopefully soon all will be answered.

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