MuffinMan

I'm heading down to Mufflex in Trenton, NJ today to have the Gundo hack done on my 2005 997 mufflers. The guy I spoke to said they've very experienced with it, and have probably done this job hundreds of times. He also said it's becoming more and more popular, at least through the eyes of his shop.

Nevertheless, he said there are two ways to do the hack. He said one way is the "external" modification method, which is connecting the two pipes together like the original Gundo hack. The other method is to make an internal modification to the muffler wherein they essentially remove one of the corkscrews to reduce the baffling. He said you get some muffling this way, he rates the "external" mod at a loudness of ~7, and the "internal" mod at ~5-6. The internal mod is supposedly a little quieter inside the car than the external, and they do the internal mod much more often than the external mod. I asked about the pipe diameter, and they typically use 2" and he claims to not notice any quantifiable difference between a 1.75" pipe and 2" pipe.

I was all set for the standard Gundo (external) mod, but now I'm second guessing myself since I haven't heard any examples of the internal mod. Has anyone investigated both variations, and/or have feedback? Video (audio) would be great!

997_Toronto

Here are the two hacks I've seen done most often. Also, would be interested in knowing how much you're being charged for the work.

Option 1:


or

Option 2:


I would go with option 2

MuffinMan

Mufflex basically does the y mod in option 2, but without the short straight piece used in the traditional gundo hack.

The shop said it is raspier with the traditional gundo over the Y mod, fwiw

997_Toronto

I've heard great things about the hack, better cold starts and much better sound. Not been able to find a decent price to get it done here in Toronto, average has been $600 upwards. How much is Mufflex asking for?

MuffinMan

They said around $300US including muffler removal and reinstall. I'll know final numbers in a couple hours.

Hyper911

I did option 2 and loved it. Very throaty on startup and a great sound under WOT. Cold it was quite loud, once warmed up it was perfect. I do like my cars to sound good, but no drone and not crazy loud.

997_Toronto

Where did you get the mod done and how much did it cost, if you don't mind me asking.

MuffinMan

So I ended up with "option 1". Option 2 looks like you'll get even less baffling through the muffler (more bypass), so I'm guessing a slight notch louder and raspier than option 1.

There have been a million write-ups on this, and I agree with the masses on the sound. It is an excellent balance of refined and relatively quiet when you're cruising and not on the throttle, but barks nicely when you womp on it.

Hyper911

I recall it was $350-400 and had it done by Tech Tune Exhaust on Norseman, in Etobicoke (not hot rod scotts they wanted $750). He did a great job.

997_Toronto

Thanks

Spoke with Steve @ tech Tunes and he's quoting $400 for option 2 including taking the mufflers off and putting them back on...so far the best price I've been quoted after speaking with over 6 other establishments. Gotta book some time to get this done...thanks Hyper911

JRoz

Sorry to open up an old thread, but Muffinman, do you happen to have a vid of the mufflers on your car? Is the consensus that option 2 is louder? I'm thinking of checking them out since they are somewhat local

MuffinMan

Unfortunately, I don't have any videos of the installed mufflers. Fwiw, I was out on a porsche drive last weekend with a handful of other cars, and several people commented on how great my car sounds. I'm in central NJ if you want to take a real world listen.