CorsePerVita

Well, I've got an appointment on tuesday to fix the exhaust on the 911. The SC has developed a leak at a weld on the cat and it needs repaired. I figured while I have it in there I may as well consider my options and see what I'd enjoy.

With a stock cat and a muffler bypass pipe, just how loud are these cars? I've seen videos on youtube but of course it's very hard to do a car justice with how loud it really is without hearing it. Unfortunately I have no friends locally with one...

I thought of perhaps a bursch muffler as well. Never had any problems with Bursch before, seems reasonable. Also I've seen cat bypass pipes too with O2 sensor bungs, does the car run any differently without the cat with a new O2 sensor in place? I've done a lot of searching and haven't found a lot of technical data on the situation, lots of exhaust clips but nothing I'm quite looking for.

I live in a neighborhood with a few other car addicts. We do have a few people around here with some loud vehicles, and a few houses down is a hotrodder running harleys with open pipes. I figure I can't get louder than that. But I don't want to be "that guy" that pisses everyone off. The car is my daily so it's seen and heard often, and I don't want it to be an earful for the neighbors. My ducati has leo pipes without baffles, and that's plenty loud (but not straightpipe harley loud) and no one has ever complained about it before. (sounds just like this lol same year, same exhaust same model )

On a scale of 1 to 10. 10 being "Turn that thing off, you're getting pulled over for the noise" how loud is a 3.0 with a muffler bypass pipe?

What would you fellas say is reasonable (if the bypass pipe isn't) as an aftermarket alternative for someone who wants to wake it up and enjoy it but not drive the neighbors nuts.

Reiver

I have a cat bypass with CO bung and a stock mufler. Makes no more noise than with the cat in place. From my experience you gain a few HP at the top end and about same thru the rpm scale with 3.0 motors. You need to dial in a richer mixture about a 3 to 4 CO.
I believe the 3.2, with its more aggressive cam profile, may lose some crispness at the bottom end with the same addition at the top end.

wildcat077

Get yourself an MK Euro "pre muffler" for your car,it has the O2 sensor bung which picks up both banks and it is really well made ...
It doesn't affect the sound in any way but you should get a good sport muffler and a SW chip as well to compliment the package !

Cheers !
Phil

theiceman

i run the same set up as Reiver .. stock muffler and cat bypass.. Sounds fine ... the car came that way with a bit of a ghettoo bypass. Loooks like soemone cut out the cat and welded in some patch pipe. but it works and cost me nothing.

Todd951968

I installed a cat-bypass with O2 sensor and stock muffler. I noticed a pump in power that could definitely be felt. (Maybe my cat was clogged?) The cat bypass also reduces the engine temps, bigtime. The sound was not much different.

Then, I installed a high quality stainless muffer bypass to the cat bypass. It was at least as loud as the loudest Harley I'd ever heard. WAY LOUD, in my opinion. The idle was a bit higher but I didn't keep it on the car long enough to need adjusting it. In a rural area, if you like true racecar sound, maybe. So, I pulled the muffler bypass and installed a Mille Miglia muffler.

The cat bypass with Mille Miglia muffler is AWESOME sounding. Perfect.

So, the muffler by-pass pipe sits in the garage shelf. If you are interested in trying out the muffler by-pass options, I would consider selling mine. Its a FABSPEED brand, I believe. Send PM if interested.

SARGEPUG

The setup on my sig is loud, but not get pulled over loud. You can go to fabspeeds site and listen to the different configurations and sort of a guage.

Ed Hughes

Don't buy the muffler bypass. It is a 9.5 on the loudness scale. If you want one badly, just watch eBay, and you'll soon find one with almost no miles or use for sale. When people buy them, they drive the car once or twice and pull the things off.

If anyone wants to hear a 911 motor at it's best, fast forward to about 1:10 on this clip of Ruby on the dyno:

rusnak

^ !!!