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911uk

Muffler bypass done

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THIS DISCUSSION / SOURCE-DERIVED OVERVIEW

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YOUR RESEARCHMuffler bypass done

Leading reported evidence

Install designtek supremacy back-boxes (that are a muffler

Performed · outcome unconfirmed

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Performed · outcome unconfirmed

I have just fitted Designtek supremacy back-boxes (that are a muffler, with a pre-made gundo hack (the small bypass pipe)).

Muffler bypass done
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Leading evidence: 'Install designtek supremacy back-boxes (that are a muffler' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Install designtek supremacy back-boxes (that are a muffler' (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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Install were the l shaped ones

Performed · outcome unconfirmed

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Performed · outcome unconfirmed · Original poster

The ones I fitted were the l shaped ones.

Muffler bypass done

Use 2.5" pipe

Performed · outcome unconfirmed

No successful repair reported for this finding.

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Reported fixes
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Unsuccessful attempts
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Discussions
Read evidence and context

Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that performed work without a confirmed outcome
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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

I think the factory PSE system used a 3" bypass pipe and this is pretty much as good as it gets for sound, I went a bit tamer and used a 2.5" pipe which sounds spot on for me but does make a great sound at the top or the rev range but with it being the 3.6 engine the bypass mod it done from the top of the silencer to the pipe in the middle, the 3.4 usually uses a much thinner pipe, I think around 1.5" - 2" and goes between the middle pipe and the one at the bottom.

Muffler bypass done

Use were the same as in the picture

Performed · outcome unconfirmed

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

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

The pipes used were the same as in the picture.

Muffler bypass done

Use i assume

Suggestion or failed attempt

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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that contain suggestions
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Suggestion

What size pipe did you use, I assume on 3.4 boxes between the two external pipes?

Muffler bypass done
Frequently discussed actions (5)

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

Install designtek supremacy back-boxes (that are a muffler

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

I have just fitted Designtek supremacy back-boxes (that are a muffler, with a pre-made gundo hack (the small bypass pipe)).

Muffler bypass done

Install were the l shaped ones

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

The ones I fitted were the l shaped ones.

Muffler bypass done

Use 2.5" pipe

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

I think the factory PSE system used a 3" bypass pipe and this is pretty much as good as it gets for sound, I went a bit tamer and used a 2.5" pipe which sounds spot on for me but does make a great sound at the top or the rev range but with it being the 3.6 engine the bypass mod it done from the top of the silencer to the pipe in the middle, the 3.4 usually uses a much thinner pipe, I think around 1.5" - 2" and goes between the middle pipe and the one at the bottom.

Muffler bypass done

Use i assume

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
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.

Suggestion

What size pipe did you use, I assume on 3.4 boxes between the two external pipes?

Muffler bypass done

Use were the same as in the picture

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

The pipes used were the same as in the picture.

Muffler bypass done
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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.

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

  • 911uk: 1 discussions

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

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Generation: 20261026T112012Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

Well I spent the afternoon fitting new exhaust pipes removing the mufflers as I found the stock exhaust a bit tame. I will be spending tomorrow taking them off again! I'd watched some YouTube videos and the bypass sounded nice and not too loud but in real life it's very very loud. TVR loud. Too loud for me. I think I will be looking for a stainless backbox to give me a bit more noise but not to the bypass level. Would like some new manifolds but the bolts on the original look like they would shear off or the heads would round so as no leaks will leave well alone for now.

POST 2Original post

Interesting to read this....I did look at complete bypasses (L-shaped pipe that completely removes any mufflers from the system) - but read that people felt they were too much. I have just fitted Designtek supremacy back-boxes (that are a muffler, with a pre-made gundo hack (the small bypass pipe)). Seems to be a good compromise, they are sensible volume, unless you drive it hard.

POST 3 / ORIGINAL POSTEROriginal post

Thanks for the info will have a look at that back box style. The ones I fitted were the l shaped ones. Will stick them on eBay as someone will be happy with the volume.

POST 4Original post

I did the 2.5 ID pipe on my 3.6 boxes years ago and I think its perfectly civilised and has a great sophisticated sound to it when on it and not too loud at all when just cruising along. What size pipe did you use, I assume on 3.4 boxes between the two external pipes?

POST 5Original post

Oh well, at least you had a go. You wouldn't have been satisfied until you'd tried them. Aren't they god awful bloody things though. :grin: I can't help commenting on every thread I see about them. They turn the car into a Chav-wagon instantly and people (well, me) just think '*****" as you drive past and deafen them. Wise move going for sports boxes. It will retain that flat 6 sound that gets lost with those delete pipes. :thumb:

POST 6 / ORIGINAL POSTEROriginal post

infrasilver I'm not sure of the exact size but they fitted over the pipe from the cat so marginally bigger maybe 3.5 inch. Marky911 you're right I felt very self conscious as I passed pedestrians and the sound wasn't anywhere as sweet as I'd hoped for. A nice sportbox would be a nice compromise as the stock mufflers are a bit tame sounding imho.

POST 7Original post

I think these are hard cars to get sounding right, I've tried a few box variations now along with the 200cell top gear cats and still I've not got the sound I'm looking for, currently back on my standard boxes with the sport cats.

POST 8Original post

It all depends where you put the bypass pipe, I am assuming you have just done the bypass mod and not deleted the "muffler" all together. I think the factory PSE system used a 3" bypass pipe and this is pretty much as good as it gets for sound, I went a bit tamer and used a 2.5" pipe which sounds spot on for me but does make a great sound at the top or the rev range but with it being the 3.6 engine the bypass mod it done from the top of the silencer to the pipe in the middle, the 3.4 usually uses a much thinner pipe, I think around 1.5" - 2" and goes between the middle pipe and the one at the bottom. The above sizes get the same sound from the different silencers so going too wide a diameter can make a huge difference to the sound and can be unobtrusively loud if too big.

POST 9 / ORIGINAL POSTEROriginal post

Hi infrasilver the mufflers were gone altogether so the tips were attached straight onto the cat pipes and out of the back. The pipes used were the same as in the picture. Saves quite a bit of weight not having the stock muffler boxes but gets too loud for me.

POST 11Original post

I have never heard of anyone doing this and actually liking it afterwards.

POST 12Original post

Ive had straight pipes from cat back on mine, though the pipework followed the original route as opposed to the above. Loved it (so did everyone else except one neighbour and they could ***** right off) but hated that it robbed it of noticeable low down torque so switched out to something else. If it wasnt for the torque issue, id have kept them on the car

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