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Exhuast Leak = Bad Performance?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 86blazerk5, May 1, 2002.

  1. 86blazerk5

    86blazerk5 1/2 ton status

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    Hey Folks,
    I have recently developed a bad leak just before my cat. The U Bolt broke and the pipe is lose and turns in the other pipe. At just the right circumstances under load I get a real bad exhaust leak rattle combination. I plan on getting this fixed pretty soon. Perhaps temperarily with a new u bolt, and soon with a new cat and pipe... Anyway, My question is, Does have a bad exhaust leak like this cuase you to lose power and get worse gas mileage? Or, do I have an unrelated problem?, Or, is it just my imagination. Thanks,
    Ike
     
  2. 86K5TrailBlazer

    86K5TrailBlazer 1/2 ton status

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    in short yes is can becuase it will affect backpressure. I fixed a few leaks on mine a while ago and found i had lost a lot more power than i thought
     
  3. 79Beast

    79Beast 1/2 ton status

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    It could be all in your head, but it is possible. If you are fuel injected, the cat keeps enough heat on the oxygen sensor to allow it to work. Also, it could disturb exaust flow and scavaging. It could also reduce backpressure and increase power. I would fix the exaust first. If your problems continue, look elsewhere.
     
  4. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Reducing backpressure increases power throughout the RPM range. I would imagine a big leak would definitely help more than hurt, especially with that big blockage the enviornmental nazis call a cat.
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    I'd say its unrelated. While I don't think a cat is necessarily a bad thing ( /forums/images/icons/smile.gif ) eliminating a well used one like I assume yours is, won't hurt anything. (except emissions if its working right)

    I had the exhaust on my previous K5 break in half, and although it was a lot louder, it didn't have any more or less noticeable power. I got it fixed right away, but that 305 just didn't care what kind of exhaust was on there, if any.
     
  6. Blazer1970

    Blazer1970 1/2 ton status

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    If the exhaust leak allows outside air to get to the oxygen sensor, it will make the computer think the engine is running lean when it's not, and then it will make the engine run really rich, which will effect performance.
     
  7. 86blazerk5

    86blazerk5 1/2 ton status

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    I think it probably is mostlty in my head, The thing is that it is loder and so maybe I am thinking its working harder thus more, power, and the powers not there, but of course its not really working harder, it is just sounding louder. I do feel that my fuel milage hasnt been as good lately, but that is probably unrelated. Thanks, for the responces.
    Ike
     
  8. k20

    k20 3/4 ton status

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    I do feel that my fuel milage hasnt been as good lately, but that is probably unrelated

    mileage? what is that? /forums/images/icons/cool.gif
     

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