DIY - $10.00 Porsche 911 Exhaust Mod (AKA Fister and Gundo Hack) 

Just to clear the air before any questions come up, this is a 911 Exhaust mod we wanted to share as an alternative to an expensive replacement. In our numerous google searches we have seen this design called a Gundo hack and also a Fister hack so call it what ever hack you like but to us it is the Full Octane Exhaust Mod.

From what I researched, gundo and fister are two different mods. Gundo is from the muffler to the nearest pipe. Fister, which is what this video is showing, is a pipe between inlet and outlet.

The origin of this input/output Porsche muffler "hack" began with the first of there construction type the '94 thru '98 Carrera 993 mufflers. .. During the present-day 993 production,, a fellow 993 enthusiast by the name Leland Pete would popularized the I/O hack. .. It became widely popular with N. American 993 owners.. About year '94 or '95 the DIY hack was widely known as the LPMM. .. The Leyland Pete muffler mod. .. That's the history of the I/O LPMM.. The DIY LPMM in our '98 C2S is still going strong since 1999. ..

Awesome!! Thank you very much for this video, very useful!

Outstanding video.

Thanks for sharing sir. You are candid and humble. When I see a couple of comments from geniuses here below. Keep the faith man!

Wow that's pretty awesome cheers

Great video! You've made it look easy enough for a software engineer to do.

I did this to my 2007 C2, I took the muffler out of the car then took them to a muffler shop , have them cut and weld they charge me $ 50 . You may says wow that was cheap, yes i told them its a Mustang muffler. Dont mention Porsche they will charge you $$$$

Beautiful sound

Those are some cool tools too. I need to get me a cutter and welder now...lol

For $10 this is a good thought. Oh by the way, The welder might drive this $10 price a 'Bit' higher than first thought.

Best way of notching the little pipe for bypassing, is just cut 1/3 of both side (from where u cut with plasma cutter) 45°straight

I gundo'd my 997.2... Awesome

NOT to be done yourself OR by most muffler shops. Simply pay $370 to Fister and have him do it since at 4,000 units done the technique is solid. Everyone else will screw up and within 2 yrs you’ll have stupid problems. That said, you’ll gain vastly more interesting sounds in 3k-5k range although above that its hard to hear the fabulous sound of the variable valve timing (vario-cam). kick in. Also, the low end sound from idle and take off is debatably Suburu-like and its louder than the ultra quiet gen1 996.1 3.4 litre motors like mine. Years later, I LOVE it. I still put my windows down to hear other’s v8s.

So $10 of pipe and $4k in welding and plasma gear

So according to forums and so on, a pipe diameter between 1.5 and 2 inches is specified, some also mean 1.75 inches. Now I ask myself what would really be the best with a 996 3.6L that you have a nice sound, but it doesn't boom, vibrate or anything else that would be an annoying noise. The main thing is that the flat 6 can breathe through the exhaust in the best possible way, even if the standard catalytic converters remain for the time being. Nice loud aggressive would be great without being at the traffic controls or the 2 year legal reviews. The engineers also know that a Porsche is louder than a standard car. So who knows what diameter of the bypass tube would be best? I am happy about your answers.

What is the cutting tool being used at 6.45?

Did it to my 2009 C2S, it was ok but it wasn't the answer. Tried it with and without the center muffler delete as well. Sounded better, which is not saying much considering the stock exhaust was extremely subdued, but still didn't sound proper.

Does this means welding stainless steel or not?

Sounds fantastic! If you’re in Ohio, I’m bringing my civic to ya. 😀

Damn, I guess you are right around the corner in Brentwood?

14:42 - OEM 15:14 - Mod I toggle between the two time stamps for back to back to back to…

I just got my 2003 boxster S I'm thinking in do this modification 🤔 but will have some issue with the smog test???? I'm in California and in these area they are really pickies

why not do away with withe baffle box? less weight..

$10 with a few thousand in tools lol. For most of us far easier and quicker to just order them modded from FD Motorsports. I also have to wonder if you are better off doing the bypass from the plug where Porsche does the bypass for the factory PSE - that still goes through 1 chamber rather than bypassing them all.

I did the same mod to my porche and am very pleased with the way it sounds. However, i started having carbon deposits on both sides of my rear finders. Anyone knows the cause and cure for this issue?

Oddly enough, I prefer the stock sound. It’s higher pitched and I don’t like the deeper tone of the Gundo hack cause it reminds me of the sound of a muffler with a hole in it (Gundo is a personal friend of mine, so I call it the Gundo hack).

Full Octane Garage which welding wire you use?

OK.... thanks for the tip .... but ... i think what if you get checkt from an Police officer for the loudness of the car ..? And second... what if it is for you at a longer trip also to loud ...? Maybe if it is smarter to install a valve betwieen so you can switch it on and off ... ?? ! ! ! What do you think ... ???

I was wandering which part of state your in my 99 911 has engine on a stand now just had a complete refresh and mow would be my best time for anything before it goes back in

When did an 08 CS become a wide-body?

Is this legal from a sound and emissions point of view (in Australia)?

Ok I'm in Milan Tn

Can this be done on a 2012 997.2 turbo? Thank you

Can this be done on a 3.2 exhaust with a cat?

The Carrera S has no widebody, only 4S, GTS etc. models..

I’m cheap and can’t weld. What happens if I just put a 1.5” hole in the pipe by the muffler and not insert/weld in the connecting pipe? Any downside?

Once you have your $1000 + setup of welder and plasma cutter....yes this may be a $10 exhaust mod. Maybe.

Why not just remove the muffler.. weight reduction

Would recommend face and hearing protection.....my save you from not being able to see or hear your grand kids.

a $10 fix with about $2K in tools