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      09-07-2011, 01:39 PM   #1
Juicehead
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Figure this one out, Weird exhaust note change...

I am FBO with a Cobb AP Stage 1 Tune. I can be just cruising along and suddenly the exhaust note will change (get louder). The car does seem to accelerate a tiny bit as well (hardly noticeable).

Could this just be a fuel mapping issue with the tune, or perhaps the ECU is not getting the correct feedback from the O2 sensors in the downpipes even?

I am out of ideas of what it may be.
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      09-07-2011, 03:35 PM   #2
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stock exhaust? could just be the exhaust flap opening up.
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      09-07-2011, 04:10 PM   #3
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Flap opens up at 1.1k RPM, so I don't think that's the case.

Maybe non even road? Little hill up or down will affect the boost.

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      09-07-2011, 04:13 PM   #4
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same thing here, I assume cam angle...
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      09-07-2011, 05:38 PM   #5
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catless DPS and full berk exhaust...

no flippity flap!
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      09-07-2011, 06:09 PM   #6
Das Ein
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Its the wastegate opening. Mine does it too.
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      09-07-2011, 06:57 PM   #7
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Yup, the sound from my car varies pretty heavily. Most noticeable to me is how much louder it first idles when coming off a highway cruise.
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      09-08-2011, 11:43 AM   #8
baylor1er
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Its def. the wastegate. Mine does this all the time at a 70mph cruise. I have strait pipes and it is super noticable. I'm so used to it that I don't pay attention to it anymore.
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