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Exhaust smell after header install

Discussion in 'SVT Shelby GT500' started by Fang, Jan 8, 2019.

  1. Fang

    Fang Active Member Established Member

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    So I had stock exhaust manifolds with an off road X and just switched to headers and off road X. My wife said the exhaust smell is not unbearable. I don't see how this change could have that much affect on the smell coming out of the exhaust considering both systems had no Cats...I too feel like the smell is really strong. I have had it out for around an hour or so cruising around to see if the new pipes just needed to burn off. Doesn't seem like it is going away. I just sent a log to the tuner to make sure all is in line. Thoughts?
     
  2. Sielmo

    Sielmo Active Member Established Member

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    If no tune change with your install, then I suspect it's related. Your tuner will be able to provide feedback and any revisions.

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  3. MastaAce03

    MastaAce03 Well-Known Member Established Member

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    Check for exhaust leaks


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  4. Fang

    Fang Active Member Established Member

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    I loaded new tune at time of install
     
  5. Catmonkey

    Catmonkey I Void Warranties! Premium Member Established Member

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    We could sit here and guess all day, but until you datalog the car and send it to your tuner, it will all be idle speculation. An exhaust leak will introduce air in the exhaust and make the O2 sensor's think it's running lean, which in turn will cause the PCM to add more fuel. Long tubes are also a lot further back from the OEM locations and may take longer to heat up. There are some things that need to be done in the tune for long tubes.
     
  6. Fang

    Fang Active Member Established Member

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    Well, datalogged and the tuner said all looks good, I guess I will have too look for leaks now.


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  7. johnnyboy081990

    johnnyboy081990 New Member Established Member

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    I have Kooks headers and catless x-pipe with a custom tune, the gas smell is def noticeable. Granted, I didn't run catless with stock manifolds, if datalogs came back good, I'd say its normal but it doesn't hurt to check for leaks. For what its worth, I also have an e92 M3 with primary cat delete, even with secondary cats in place with custom tune, I still get a mild gas smell, no leaks.
     
  8. Catmonkey

    Catmonkey I Void Warranties! Premium Member Established Member

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    If one bank isn't compensating more than the other, chances are it's not an exhaust leak. I'm not sure what you told the tuner when you sent him the logs. If you told him about the gas smell and he looked at the log, chances are that's just the way it is. I don't have cats, but I also lived and drove in the era before cats, so I'm not sensitive to it.
     
  9. Islandcat

    Islandcat Member Established Member

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    I went the same route as you. Off road pipe. Then headers with off-road pipe. It smelled the same to me. I didn’t notice any difference honestly. I know that doesn’t really help you, but I don’t think their should be any difference from changing to headers.

    Did you use same tuner for both tunes? Maybe this tune is a whole lot richer if it’s a different guy. Just a thought.
     

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