I have purchased a used set of 997S mufflers (4K miles) to do the Gundo hack on my 997S. I wanted to keep my original mufflers for resale purposes. Hence the purchase of the second set...

My question is this...what size pipe to go with??? I see that Fister uses a 1.75" pipe on his similar mod. Gundo uses 2". Some Gundo mods have used 1.75" pipes. I want it to sound good but not obnoxious. Should I go with 2" or 1.75" pipes?

I am not offended by a throaty sound. I had a 964 with no cats and a Billy Boat Triflo exhaust that was the best sounding 911 I have ever owned. And, it was one one the best sounding 911's I have ever heard short of a race setup.

I just want some feedback from those that have performed the Gundo hack with these two diameter pipes. Thanks in adavance for your help!

Doug

 

Where do you plan on having it done?

 

I am still researching local muffler shops. I am not sure yet. I hear they deal with this type of stuff daily. I intend to tell the manager that I will pay extra for their best fabricator/welder. Hopefully that will provide a good result.

 

I split the difference and went with a 1.5" diameter pipe. VERY happy with the sound. I wanted to err on the side of caution because I did not want loud----I wanted throaty and mellow, which is what mine sounds like. I have had MANY compliments and NO resonance on the freeway.

 

I did the Fister hack. His shop is next door to my office, very sweet.

W don't you just contact Darin and do a trade? Send him your used ones....he sends you hacked cans....done....no searching around. Mine sound so sweet....can't get enough of the sound!

 

Given your exhaust history (catless...etc) definitely go 2". I LOVE the sound of mine.
Arguably a better sound than PSE. Nice and deep. You're going to be underwhelmed if you go anything lower than a 2" diameter. Good luck!

 

same with my 2 inch.... I suspect they are not much different at all.

 

2" is the way to go. Run it with 200 cell cats and it is just fabulous. No resonance whatsoever. Nice burble on throttle blip too!

 

I also used 2in, no regrets, sounds GREAT!

 

I just had mine done and went with the 1.5" ss pipes. What's great is that they only sound loud when you want them to, e.g. aggressive driving.
They kick in around 2800 rpm and sound best IMO at around 3500 rpm. And, at least in my case, it's a growling sound that says Porsche. It's the best.

 

Hey Sullivas. What shop did you use for your Gundo hack(I live in central CT)?

 

911 CT - I used a shop in Danbury, CT. Not sure how close you may be...must be a custom shop near Hartford...

 

I used 2" and it was nice, definitely worthwhile, but still not quite enough. With 200 cell cats, headers and intake, it was fantastic! As Gundo says, the bark on throttle blip was fantastic and then starting from 3500k to redline it built up to a wonderful aggression.

I used Unlimited Autosport in Oyster Bay Long Island -- nice job and price.

 

Thanks for reply, Gundo. I live next to Waterbury, so Danbury is just fine for me. Could you pm me with the name of the shop please?

 

Thanks to everyone who responded! Even the master, Gundo responded.

It seems clear to me now that the 2 inch pipe is the way to go. That is what I will have installed. I will give a follow up post once I have them installed.

Thanks again guys!

Doug