Hi, yes I did use the 2" pipes. I was worried it would be too loud. Not just for my neighbors, but more importantly for my girlfriend who has some hearing damage and loud noises can be really problematic for her. I was relieved that it isn't really that much more volume as it is the increased range of tone that you hear from the engine.

 

It WAS a challenging thing to to do, because once they burn the holes on the pipes, you are committed, because to go back you have to buy a new exhaust!

Thankfully it truly was the right thing fir me and I really believe the mufflers should come stock like this.

As far as finding a place that you are comfortable to do the work, this was my approach. I found a muffler shop that had been around for a long time, (17 years ago the fitted my 5 series with a cherry bomb glass pack) asked them if the could do the work and went for it.

Muffler shops cut and weld all day. In fact, they had a 1930's minted out pick up in there today and were going to have to completely fabricate the entire exhaust. Howard, the guy who did the work said with a lot of older American cars, they end up having to cut, bend and weld things back together all the time.

Once you find a place like that, call them and then email them photos of the Gundo Hack. Once they see what is involved it should be very easy for them.

Good luck and keep me posted on what you find!

 

Let me ask!

 

What year is your car? Also, did you leave everything else stock? Have you thought about adding the sharkwerks by-pass?? I am in the Denver area (Arvada), and I am 99% sure I want the Gundo. Anything negative yet from having it done? Seems everyone has only positive things to say, are there any negatives?????

 

I am in Denver too and want this done. Is Howard the guy to call?

How long did it take to complete?

 

Any decent exhaust shop should be able to do this. the result isn't wider range but not louder by that much. if i were to do it again, i'd go aftermarket for a fuller sound. for those looking for a little more oomph with a little money, this does the job.

 

Hi! Mine is an 07 Targa 4S, with stock everything. I just had it done today and I really like the sound improvement. Before, I seemed to be reving the engine up higher, not just for the gpfeel, but to hear it. Now it sounds terrific starting around 3,000RPM.

I did think about a bypass, but feared they would be louder than I wanted. I don't think Sharkwerks makes a bypass for the 07 997 4S.

Don

 

Howard did the work and Mike was the guy up front that I spoke with. My car was there 2.5 hours. The Gundo Hack took 2 hours and they waited initially .5 hours to let it cool down before they started. I definitely recommend it.

Don

 

Atta boy! I did the Gundo Hack to my '06 C2 years back and still leave the drivers door open when I start the car. I have not heard a better sounding system regardless of price and unlike some $$ exhausts there is no droning inside the cabin.

I pulled my mufflers myself (if I can do it anyone can) and took them to a muffler shop with pictures from Gundo of his hack cans.... hardest part of the entire job was aligning the exhaust tips

Here's my car: http://www.youtube.com/watch?v=Vf0NpWNAj78

Best,

Matt

 

i'm sure there's tons of threads on my next question but since this thread is currently at the top of the forum......will this hack decrease power? something about back-pressure issues? i dont care if it helps me gain HP's but i certainly dont want to lose any. (FYI, i obviously have no idea how an exhaust system works entirely, so apologies for the stupid questions!)

 

Thanks! I watched the videos over and over again and they don't do the exhaust systems justice. Even the before and after videos, while they give you a hint of the difference, it is not the same as being enveloped in the sound.

Great license plate! Just don't get pinged by a state boy!

 

I feel it is a wider range as less of the engine sound is muffled by the muffler. Much more throaty and more tone. Maybe its because I can hear it better because of the slight increase in the decibels, but I really feel like I can hear the engine tone across a wider range.

 

Hi. I had heard that comment before too. I do not feel any loss in HP AT ALL, but that is subjective.

I dismissed the lower HP comments as improbable because anything that reduces exhaust pressure should be beneficial rather than detrimental to HP. The modification is simply a by pass pipe before the muffler inlet to the tail pipe. So some of the exhaust does not go through the muffler it goes directly out the pipe. The exhaust will naturally flow to its least resistance, but I do not know what percentage actually flows out the tail pipe and not through the muffler.

At 2", the bypass is about a 1/4" smaller than the muffler pipe, so that should allow a lot of exhaust to escape, however the muffler is a straight line down the pipe, so my assumption is as the muffler pressure builds, more exhaust is thieved through the bypass pipe. But is a theory not based on any data or engineering; also known as a guess.

A contrasting experience to the theory is I hear the sound the moment I start the car. Could that be due to the sound traveling faster than the exhaust?

So I don't know for sure, but I can say, I feel no HP loss and because of the sound from the engine, I feel like the car is faster. In short, the car sounds more like a sports car and that has enhanced my driving experience.

 

Alan, you're a smarter man than I am, because you asked this question before you did the work!

On my hack they used aluminized steel, which is the common muffler material rather than stainless steel. Mike said they could do stainless for $50 more. I asked about the stainless vs. the aluminized steel and he said that the stainless in exhaust systems is not pure stainless and it can rust over time. He said on normal long exhaust systems they expect the aluminized stainless to last 8 to 10 years. The rusting starts from the inside and that it is more of an issue for cars that sit for a long period of time.

I told Mike my car will sit over the winter and he felt that would not be an issue as the proximity of the muffler to the engine, makes the mufflers extremely hotter than a standard front engine, back muffler configuration, so it is less likely that condensation will have a chance to occur.

Additionally, that 8 to 10 year average is based on cars out in the elements all winter long starting and sitting daily with long horizontal stretches of exhaust pipe. So I bet, a 911 that is always garaged and not driven in the winter, will exceed the average.

Finally, looking at the Gundo hack, the bypass pipe sits at about a 45 degree angle when installed (see picture below - think about the muffler based on the exhaust tip orientation once installed), so any moisture would naturally drain back to the stainless inlet pipe.

All in all, I don't think it will be a problem, but if it is a concern, ask for stainless.

I cannot over estimate how much more throaty the engine is, I say do it!

 

Anyone have an 09 S that has had this done?