tejoe

Gundo is the guy who started doing this several years ago (just search "Gundo Hack" on 6speed). All you are doing is partially by-passing the 3 stage baffles in the muffler. While Bruces' sounds pretty good I have to agree with rijowysock that 2" is the norm and yields a little more noise. FWIW, you can get this done in any decent muffler shop for under $100. Don't expect any performance uptick, but that is not the purpose.

Mspeedster

^Thanks!

rijowysock

yepp..

as i noted.. on 997.1 it is louder than 997.2, 997.2 if you do the center bypass as well then it gets around the same as 997.1 with only side bypasses'

on 997.1 try and get it as vertical as possible when on car for most gurgle and pop..

on 997.2 my guy had to use slightly bent pipe to make it work cause was nearly impossible otherwise to get the pipe in there cause the odd angle of the pipe's.

sound is just phenominal, i get people in porsches and other cars all the time asking me what exhaust i have, then i explain it cost like 200$ and sounds amazing, the car does seem to rev more freely with the bypass to me as well as the OP stated..

the double hack as shown has been done by a few people but i still dont understand it.. i dont know where the 3rd hack enter's and why it would be neccesary.. the point of the hack is for when the pressure builds up in the muffler the pressure causes the exhaust to take the "easier" route thru the bypass pipe and out the rear.. ferrari has used this on cars for quite some time and its essentially what the PSE does (but the pse opens and closes) this is open all the time BUT the gasses pretty much flow thru the muffler until higher RPM's

my car sounds near stock until around 3k rpms which is perfect for no drone on highway, no annoying drone on casual drives... i cant stand loud all the time straight pipes as i get frequent headaches and want quiet at those times.


the hack is louder on cab's because the sound reaches the cab much easier so take note of this.. if you like on a coupe.. it will be louder when inside a cab.

rijowysock

also, causes no lights on 997.1 or 997.2 as its past all the sensors... just sounds great, no downsides.


your gas mileage might go down a little from all the gas blipping you'll be doing.. the pop and gurgle alone makes it worth every dime.

Rambler358

Okay, home from work and finally got to hear 'em - very nice!

Did you ever get a chance to record before and after clips outside the car per chance? The inside sounds nice, but not over-bearing - perfect I think.

Bruce R

Hey Ron I've yet to record the "after" clip. I wanted to do it in the same manner as the "before" and I need my wife to help with that. Got some winter weather coming in (North Carolina) but by mid next week I should be able to get a good "after" clip.
At the beginning of the YouTube clip it sounds like it's droning in car but in reality it does not at all. Really happy, subtle yet a deeper more gravelly tone.

larrytrk

Any pics of 997.2S hack.
I have an extra set and am thinking of having it done for later.

CamsPorsche

This is a great little mod! Thank's OP. I plan to do this when mine arrives...

rijowysock

no pics as its on the car and hard to take from that angle..

he just used some bent 2" pipe cause u couldnt get a straight one in there without having a weld 1" thick.lol

Bruce R

Here is a picture of an OEM PSE (top) showing what my, lets call it a "modified Gundo" or mGundo, muffler is trying to achieve. I've got a cross pipe (not present on a PSE) of a slightly smaller diameter IN ADDITION I'm using the same exit from the back of the muffler can as the PSE. The difference being that on a PSE the tubing from that back exit then runs all the way to a double exit at the tips. Hence the extra weight of a PSE over a standard OEM exhaust I'd guess? MGundo just dumps back into the nearest tube to exit. PSE also contains a switch, Gundo's are always ON!

We'd need to compare my mGundo with a Gundo side by side but I'd guess it's about the same result noting that the mGundo uses some of the Porsche PSE technology to enhance sound.

CamsPorsche

Just to clarify the additional pipe in between is added to both sides of the exhaust (L&R)?

rijowysock

yep.

atr911

So here's my problem....

The original muffler is stainless correct? I drive my car all year and there is salt on the road. I would really like to do this with stainless steel but I'm not sure what grade/gauge to get. Also, what composition welding stick should I be using for this? My tech says he'll do it if I take the cans off.

Any specific info would be appreciated.

mickfluff

Here is mine from outside the car w/drive by and rev+ pull away...Hacked mufflers on 05 with EVO Air box....

http://www.youtube.com/watch?v=9r7JnY4rF2M

Axxlrod

Sounds good, Bruce. What kind of camera set-up do you have in the car?