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Strange exhaust noise?

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2 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis

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YOUR RESEARCHStrange exhaust noise?

Leading reported evidence

Replace backboxes

Performed · outcome unconfirmed

No successful repair reported for this finding.

0
Reported fixes: 0
Unsuccessful attempts: 1
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Discussions that performed work without a confirmed outcome: 1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Performed · outcome unconfirmed · Original poster
I took it back and they changed the backboxes for some that were a similar size to the stock ones, these are a lot better but still when the car is de-revving it sounds like the car is farting...
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Strange exhaust noise?

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Leading evidence: 'Replace backboxes' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Replace backboxes' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.

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1 matching discussions · 2 captured posts examined · 0 partial discussions

Frequently discussed actions (1)

These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.

Replace backboxes

No successful repair reported for this finding.

0
Reported fixes: 0
Unsuccessful attempts: 1
Discussions

Read evidence and context

Discussions that performed work without a confirmed outcome: 1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Performed · outcome unconfirmed · Original poster
I took it back and they changed the backboxes for some that were a similar size to the stock ones, these are a lot better but still when the car is de-revving it sounds like the car is farting...
Original post Read captured discussion
Strange exhaust noise?

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Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.

2 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.

Rennlist: 1 discussions

0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.

0 acknowledgements have no verified action link; they do not establish a repair result.

Generation: 20261027T003124Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

mHi All, I recently purchased a 996 C2 3.6, the O/S exhaust was blowing so I went down the after-market exhaust route. I got one made by LongLife in Leeds, the first set of backboxes they installed were very small and made the car sound like it was farting everywhere, especially when warm. I took it back and they changed the backboxes for some that were a similar size to the stock ones, these are a lot better but still when the car is de-revving it sounds like the car is farting... it only happens when the exhaust/car is warm, when cold it sounds fine. It happens from both tailpipes, the best way I can describe the sound is a fart / flutter, like the air coming out of the exhaust is been sucked back in or something. There was a post of here with a guy and his 997 and he has a FVD exhaust who described a sound like a clown fart? He posted a vid but its set to private on youtube so I can't listen to see if I have the same... the thread never had a conclusion. Any ideas on what it could be?

POST 2 / ORIGINAL POSTEROriginal post

link to post which Id like to see the vid of... https://rennlist.com/forums/997-turb...-my-turbo.html

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