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Exhaust bypass pipe mod - using different diameter pipes

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YOUR RESEARCHExhaust bypass pipe mod - using different diameter pipes

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Use different diameter pipes

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Suggestion · Original poster

I've heard of using different diameter pipes for the bypass, I believe 1" is the standard, so will 3/4" produce less DB's?

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Exhaust bypass pipe mod - using different diameter pipes
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Leading evidence: 'Use different diameter pipes' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Use different diameter pipes' (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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Use different diameter pipes

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Suggestion · Original poster

I've heard of using different diameter pipes for the bypass, I believe 1" is the standard, so will 3/4" produce less DB's?

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Exhaust bypass pipe mod - using different diameter pipes
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3 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.

  • 911uk: 1 discussions

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POST 1 / ORIGINAL POSTEROriginal post

Hi all, have a second hand set of standard back boxes for my 3.4 C2 and want to get them to Hayward and Scott for the bypass mod but bit concerned about how loud it will be when combined with the new stainless steel headers (JDM Honda from eBay) that will be fitted at the same time. I've heard of using different diameter pipes for the bypass, I believe 1" is the standard, so will 3/4" produce less DB's? And what effect would this have on the sound, tinnier, only at higher revs? Just looking to keep my every day driver civilised whilst adding a bit more aural excitement, any experiences appreciated. Chris

POST 2Original post

Not sure how they will sound with the headers, but a smaller diameter will be quieter and tinnier (possibly raspy too). There is a chance the Venturi won't kick in until latter revs/larger throttle opening. The sound pressure level will probably drop by about 3dB. So with normal headers 99 dB.

POST 3 / ORIGINAL POSTEROriginal post

Thanks, I think I'll give it a go and if I don't like it I'm sure there will be somewhere willing to upgrade to the modded back boxes.

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