Carrera_DAWG

I know there are tons of threads on here and elsewhere discussing the Gundo, PSE and Fister mods but I have a question for input. Very confusing to try and figure out what posters are referring to between Fister and Gundo. I plan to do what I would refer to as the PSE mod on my 2005 997.1 C2 where you put a new pipe between the closed outlet on the muffler and the existing muffler outlet pipe. That is route I've decided to go as from what I have gathered seems to be a little "milder" sound level than the Fister. However, I would like to hear any feedback on what diameter pipe I should use... matching, smaller or larger? Thanks!

jamesinger

If you are going to do DIY, there are TONS of threads on it.
If you want someone to do it for you, just send it to FD Motorsports.
there are also MILLIONS of pipe diameter discussions.
link

To not be snotty though, I just went to FD in person and let Darrin do his magic because I felt like there was too much info. online that contradicted everything. Darrin has it down to a science.

Also, I will add that I think all those mods pretty much sound the same. In person, I have heard the PSE, the gundo type you describe above, and the Fister. I might be losing my hearing but the differences are negligible. I always tell this story where I was waiting for my car and I thought I heard it but it was a guy with a PSE starting his car to pull it into the garage. Then, when they started my car, he popped up thinking it was his car.

Carrera_DAWG

I live in Georgia and plan to have the work done at a local exhaust shop. Like you said, there are tons of links on size pipe to use but every time I start reading them seems like they are talking about the Fister mod where you are connecting inlet to outlet. Even tho they say Gundo mod once you read and see pics that are posted it is a Fister mod they are referring to. I was just wondering if the pipe size used to run from the closed exhaust outlet to the exhaust outlet pipe (what I think of as making a non PSE muffler into a permanent PSE muffler) would be the same sound difference as if you were doing the Fister. I have not found a direct discussion of pipe size related to this particular mod, only the Fister. I do not have a sport exhaust currently and am thinking going to a permanent PSE configuration would be a little "milder" sound than the Fister mod.

Basically, I'm just trying to figure out any sound differences in pipe size used for a non-Fister mod.

jamesinger

I will search a bit more because I am interested now. I do know fister is 1.75" from my memory, so I just assume that the gundo or PSE hack type would be 1.75-2" range.

EDIT: I think what you are referring to is the Hanksville Hack style
https://www.hhrproducts.com/porsche-...-modification/

...like I said, the pics. go from kind of beautiful to horror movie in the threads...so it is hard to get the right info at this point.

"This kit includes two mandrel-bent bypass tubes made from 2" 304 stainless steel tube. Both bends have been cut, notched, and test-fitted onto actual 997 (non-Turbo) mufflers to ensure a quality fit. You would install and weld onto your mufflers using our included instructions. Muffler removal and reinstallation required. This is an easy modification that you can perform yourself if you have access to a welder, or you can have these welded at your local shop."

Carrera_DAWG

Excellent find! That's exactly what I'm wanting to do and they are using 2". Thanks for digging up the vendor link. That's one good vote for 2" pipe!