rear mufflers

devans · Apr 14, 2011

Im aware that some silencers are modified, ie stripped down and have bypass lines put in, then re sealed. I think they are referred to as 'sports exhausts' with muffler bypass mods fitted.
Does anyone know if this can then be fitted without the need for altering anything. Will it give a power boost or power reduction at low speed etc.
I would like to be secure in my own mind that simply replacing my worn out mufflers with sports mufflers is going to be ok,
Thanks.
ps Is this also something that insurance companies need to know and does it affect premiums.

Richard_Hamilton · Apr 14, 2011

The by-pass sports exhausts aren't stripped down at all. The tube is welded externally.

There is no increase in power, just noise. IMO it is the best mod you can do. [

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devans · Apr 15, 2011

Thanks Richard, i think i will double check what im looking at.

steve r · Apr 15, 2011

I've been looking into this and there seems to be a few different ways of doing it depending on engine size.

Pics of the different ways i've seen so far:

Smaller pipe for 3.4? Larger pipe from corner of box for 3.6?

devans · Apr 15, 2011

Does it matter if you end up putting a 3.6 design on a 3.4?

Richard_Hamilton · Apr 15, 2011

IMO you should go for photo 1 or 3 - both achieve the same result, and you won't be disappointed. Photos 2 and 4 bypass half the silencer, wheras 1 and 3 have a smaller bypass, but to the whole silencer. I used 1" x 16swg tube and mandrel bends as shown in photo 1, but if I was doing it again, I would use the same size tube, but fit it where shown in photo 3, as it issimpler and cheaper.

I know several people who used the same mod as mine on 3.6's with no problems.

minny · Apr 16, 2011

ORIGINAL: Richard Hamilton

The by-pass sports exhausts aren't stripped down at all. The tube is welded externally.

There is no increase in power, just noise. IMO it is the best mod you can do. []

I totally agree. Best mod on my own carrera.

TISPKJ · Apr 19, 2011

Also note photo 3 is a 997 box

best is as said above photo one, but pipework should be between the inlet and outlet.

Just depends how good you are with a plasma cutter / and welding.

rickware · Apr 20, 2011

How loud are they, will it pass a normal trackday noise test. I think they said mine was 98 db anyway so not much more to break the noise limits.

devans · Apr 21, 2011

Wow, how lucky was i. Bought myself a sports exhaust on ebay for a winning bid of £271. The chap said they were rust free and off the same year car as mine with the same engine size. Drove 140 miles to pick them up and they were fantastic. All fitted now and car sounds brilliant.
Wouldnt normally buy an exhaust (muffler) second hand but this time it has certainly paid off. Yippeee!