"Bi-modal" exhaust?

[911pcars]

If you're so inclined, install a second outlet on the other end of the muffler, then install one of these remote-activated exhaust cutout devices in the tailpipe. Configure the tailpipe downward so it doesn't show. Should be louder, but loud enough? There's always the internal sport muffler mods as well. YMMV.

Sherwood

[Dezzmo]

Ps if anyone knows the issue of 911 & Porsche World referenced below that wd be great

I found the article and I am embarrassed to say that was in the May 2007 Issue of GTPORSCHE Magazine

Chris Harris mentions that some WRC teams were using electric A/C but probably wouldn't share the technology and then goes on asking for leads. The article in that issue was Part 2 of his ST build and the few other issues that I have do not mention the project.

I'll check the GTPORSCHE site and hopefully I'll find something in their database.

[Mbremith]

Thanks everyone, plenty to go on with now. I have a less than pristine standard exhaust perfect for experimentation (has been converted to 2 outlet at some point then back to single) so will report back on progress and results for anyone interested. Ideally my goal will be to maintain a standard single outlet look so I think I will be putting 2 gas paths inside, one silenced, one not, with the actuator on the outside where you can't see it.

[kenikh]

Here you go.

[Mbremith]

Thanks Kenik. Have you had it working on a car and if so how did it go?

[911pcars]

This is how it would sound if you connect it to a Vette engine:
<iframe width="560" height="315" src="//www.youtube.com/embed/2TrycvqeEmY" frameborder="0" allowfullscreen></iframe>

As the name implies, the above example bypasses the muffler entirely.

[kenikh]

Haven't had it running yet. PO said it worked great.

[kenikh]

BTW, that Vette sounds awesome!

[Kaefer]

Perfect, thanks Scott.

You're welcome. BTW - before I sold my last naturally aspirated 911 one of the projects on my to-do list was to install an electric exhaust cutout on one of my outlet pipes. I even thought about wiring in the exhaust cutout to open with the opening of the 3.6 resonance flap but of course never got around to it.

My 3.6 engine ran fine with one 3" outlet capped (much quieter with no drone) and of course ran great with both outlets open (wake the dead loud). For most of my street driving I much preferred a single outlet. However I found a decent compromise setup with Car Chemistry inserts in the outlet pipes.

[kenikh]

That was also my intention on the 906 replica: have the opening keyed off the RPM to open just when power would drop when capped.