Right, who's got valved bypass pipes?

[Pete Ansbro]

I'm told it's an easy job for a welder to fabricate bypass pipes with lever controlled butterfly valves to give the ol' 996 a bit of split personality.

Who's here with them and how often do you go from loud to quiet, or vice versa?

 

[924nutter]

Don't see the point. I have 100 cell stainless cats on a tubi system no swiitching. lovely growl to howl, slightly intrusive but even that is 101 db. If you have a bypass and are close to the noise limiits on track days the chances are you will not be allowed on the circuit. For example if i'd had a switchable system Bedford would not have let me in. Don't let my opinon sway you though its your car so if you want to do it do it. Mind you this is on a 996turbo Cab

 

[Pete Ansbro]

Hi 924, thanks for your input (don't you wonder why there's so little action at these fora?)

I'm not for trackdaying so that's not an issue. It's just that there are plenty of times when I miss the big bore hooliganesque growl of the TT stainless exhaust on my MGF. See here for details
http://www.youtube.com/watch?v=tDsm6Cm3jrA
playing the link now makes the hairs on my neck stand up!!!

I love my 996 Cabrio but there are times when dropping two cogs doesn't give me as much music as I would like, that's all.

 

[Richard_Hamilton]

I guess you could put lever valves in the bypass pipes, but it would be a real pain to access them. I would just go for the simple bypass pipes. You'll find that it makes little difference at low revs, but once you get past 3000 rpm it gives a lovely howl.

 

[Pete Ansbro]

Hmm, well that could do it for starters...

 

[924nutter]

I hear what you are saying regarding sound, mine sounds absolutely delightful, and I am surprised Richard hasn't heard it when I am howling down the A404 trying out my 0.8 bar boost test in second. On a feathered or light throttle the noise is not that bad as I have said before. I just think all those valves and extra pipes add a level of complexity, and weight at the worst end of the car to add it. How much of a saving versus a decent system is there too be made?

 

[Richard_Hamilton]

The Turbo and Carrera systems are vastly different, and it is relatively easy to add a 1-1.5" stainless steel tube to the Carrera exhaust between the inlet and outlet pipes of the silencer, to mimic the "Mk 1" Porsche Sports Exhaust. It adds about 250g, so no great weight. I seem to recall one of the members paid about £150 at Style Dynamix (Hounslow) for the mod, compared to about £600 for a pair of sports silencers.

 

[924nutter]

Worth doing then just for the sound. £!50 on a 996 budget is peanuts. It was all on mine when I bought it. I have been told that it has quite a howl when you are being overtaken. It is very reminiscent of the single pipe 930 but sadly without the fan whine, which is part of the experience.

 

[Pete Ansbro]

Right then. I think this goes on the list for when Ted is in for service/work next year. I want to be able to swan about quietly with Her Maj when she wan't quiet, suave and sophistication. Then when I want to make progress assertively a little extra "attention seeking" will not go amiss.

 

[Richard_Hamilton]

If you are in Essex, Hayward and Scott do the mod. Might be worth contacting them for a price.

 

[devans]

I also have the by pass pipes fitted and as Richard said....
Start up is extremely noisy
Low speed not that much difference
Over 3k revs or dropping down gears very noisy.
Hence why a switch off and on switch seems pointless unless of course money is no issue
All the best.

 

[Pete Ansbro]

ORIGINAL: devans

I also have the by pass pipes fitted and as Richard said....
Start up is extremely noisy
Low speed not that much difference
Over 3k revs or dropping down gears very noisy.
Hence why a switch off and on switch seems pointless unless of course money is no issue
All the best.

Oh money's an issue allright.

Say, what's the chance of you playing us a recording of the sound of your exhaust please?