Exhaust help

Discussion in 'General Chevy & GM Tech Questions' started by 1BadSierra2011, Jan 3, 2013.

  1. 1BadSierra2011

    1BadSierra2011 Member 1 Year

    Well I have taken off everything on the 2011 sierra, from the cats back. I had it straight piped and loved the sound it was awesome. But it seemed to gain some sort of a knocking noise, so I put a flowmaster back on. My question is how can I straight pipe it(cats back) without causing any damages. Or does it cause any damages at all? Thanks guys!!
  2. mfleetwood

    mfleetwood Epic Member 5+ Years ROTM Winner 5000 Posts

    I moved your thread here as it should generate more responses/opinions.

    Someone should be along soon who could provide you some insight.
  3. Conlan Rose

    Conlan Rose Epic Member 5+ Years 1000 Posts

    You may actually lose HP because you have removed to much back pressure.
  4. 1BadSierra2011

    1BadSierra2011 Member 1 Year

    I was told it could mess up my motor but i dont really know much about gas engines.

    - - - Updated - - -

    I plan to have it true dual straight pipe from the cats back, dont know if this will hurt it or not, anything i could add to gain more back pressure yet still have the same exhaust sound?
  5. 1BadSierra2011

    1BadSierra2011 Member 1 Year

    Any help? lol
  6. ahmitchell1

    ahmitchell1 Rockstar 4 Years ROTM Winner 1000 Posts

    If your running pipes all the way to the back you should be fine running straight pipes just don't run anything over 2.75
  7. 1BadSierra2011

    1BadSierra2011 Member 1 Year

    Will the dealer still cover damages if its straight piped? as long as it is cats back should be fine right?
  8. mudpuppy

    mudpuppy Rockstar 100 Posts

    the dealer will seek out any and all reason to void responsibility. as for the knocking noise, thats detention due to low restriction allowing for a fuel build up causing a continued burn down the pipe. this will/can effect the engine. straight pipes are nice and can be done easily by crimping the pipe around the same location that the cats would be to maintain a proper back pressure. make sure to crimp past the o2 sensors, not in front of them.
  9. 1BadSierra2011

    1BadSierra2011 Member 1 Year

    Is there any muffler I could put on that sounds like straight pipe? I love the popping and loudness
  10. Boonduff

    Boonduff Rockstar 4 Years 100 Posts

    The Cherry Bomb Glasspacks sound pretty close to straight pipes. Try and find the shortest ones you get.

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