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YOUR RESEARCHGundo
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Repair mufflers also had some cracking so those
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My mufflers also had some cracking so those were repaired at the same time.
Leading evidence: 'Repair mufflers also had some cracking so those' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check youtube "gundo hack 996"' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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I was going to go with the 2" like I've read in the forum, but my muffler guy said it wouldn't be easy to weld up to the existing 2" pipe (not enough to work with I guess when trying to get a clean weld to pipe).
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Total cost = $200, although I did the labor myself (remove rear bumper cover, disconnect exhaust pipes from the cats, pull rear wheels off the car, and then remove the mufflers - take them to a welder and explain what you want).
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I was going to go with the 2" like I've read in the forum, but my muffler guy said it wouldn't be easy to weld up to the existing 2" pipe (not enough to work with I guess when trying to get a clean weld to pipe).
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Total cost = $200, although I did the labor myself (remove rear bumper cover, disconnect exhaust pipes from the cats, pull rear wheels off the car, and then remove the mufflers - take them to a welder and explain what you want).
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There seem to be a few ways to "HACK" the 996 mufflers..connecting the inlet and outlet pipes with a short "connector", opening what appears to be a closed pipe fitting at the other end of the muffler, and making a pipe connecting to the exhaust side of the muffler, doing both or actually opening the muffler itself (like Fister) and modifying it...(Or all 3) ???
I'm confused as to what to have done....I don't want LOUD, just a bit more when accelerating..
I'm going to have a local shop do the Gundo in a couple of weeks. Stainless tubing. I'll try and post some before and after sound clips. One question I have that I don't think I got a clear answer on when reading through hundreds of posts on various forums, was the increased heat in the engine bay. Have those of you that have done the Fister/Gundo really experienced a noticeable increase in heat?
Kyle
Shouldn't the exhaust be cooler? You are bypassing some of the muffler which traps the heat. The hot gases are exiting the exhaust quicker which should lower the temps.
The mufflers provide some insulation and the exhaust gas temp would be lower on the tube exiting the exhaust than the temp going in. Bypassing the muffler, the bypass tube would have more radiant heat coming off as more hot exhaust is bypassing the muffler.
You know, after spending so much time reading about these mods, I dreamt about mufflers all night last night. Woke up EXHAUSTED.
The inlet/outlet by pass (1.75” stainless) created by Fister appears to be the best way to go. Not too loud.
Doing mine soon and the posts indicate the Gundo or PSE style is quieter and perhaps not sufficiently louder for the effort.
I did the Gundo hack a couple months ago with 1 1/2" tubing. I was going to go with the 2" like I've read in the forum, but my muffler guy said it wouldn't be easy to weld up to the existing 2" pipe (not enough to work with I guess when trying to get a clean weld to pipe). Regardless, I love it. It is not overboard like some of the rice rockets with the coffee cans, but throaty when I get on it and quiet when I keep the rpms down. Puts a frickin smile on my face when I go above 4k! I don't need anything else to make me happier with the little I spent. When the system is worn out, then I'll look at a complete exhaust system mod, probably with Dundon. Their work makes me drool, but you gotta have the money for that one.
Are these modifications on top of factory sports exhaust or do they mimic factory SE? Please help the unknowing, thanks. I have factory SE and love the sound, but I have nothing to compare it with mod wise.
There's a few threads on this. I've done both ways ( Gundo, then Fister). I much prefer the fister. The gundo (PSE Style) was barely any louder than stock. I paired both with my catless x pipe. You can compare the differences between the two in the videos below:
ZZlpsxzl.jpg
"Gundo" muffler with x pipe
You Tube
"Fister: muffler with x pipe
You Tube
This is the terminology that plagues the our community. Two things mean differently to different people. There's no right answer because it's so convoluted, but my common understanding is this:
The "Fister" mirrors the muffler modification done by Mr Fister / FD Motorsports which welds in a partial bypass to the stock muffler --
https://fdmotorsports.net/shop?olsPa...t-modification
(I was not interested in shipping my mufflers across the country so I had a local shop perform the same mod)
The Gundo term has been around for years and is the "original" stock muffler hack to mirror what the PSE muffler is at a fraction of the price.
The only internal muffler modification is to cut the muffler open and remove all baffling. There is not a terminology for that besides maybe calling it a "Fool The Feds" mod. If you're going to go through that trouble, buy the $100 ebay muffler deletes and enjoy the weight savings (and drone)
Hope this all helps in your decisions
Someone PLEASE explain ..... Fister (or Gundo) is the short pipe welded from the intake to the exhaust side of the muffler....what is the "other" mod called, the one where the "sealed "port" at the other end of the muffler is opened and a pipe run to the exhaust side of the muffler???
dak911
Look at the photo Vipertag313 posted showing the Fister and the Gundo mods. Notice the bypass pipes - Fister and Gundo are two different designs. When the sealed opening is removed, it is the Gundo mod.
True. I call mine Gundo even if it�s not 100% correct.
My first thought to respond to the OP was �do a search,� as there are many threads on this topic. Possibly dozens.
I had a welded pipe bridge the gap between the intake and exhaust portions of the muffler. Total cost = $200, although I did the labor myself (remove rear bumper cover, disconnect exhaust pipes from the cats, pull rear wheels off the car, and then remove the mufflers - take them to a welder and explain what you want).
There are so many different "explanations" hopefully you are right...I have heard the "bypass" (short pipe between the inlet and outlet called "GUNDO"
Can someone explain the difference in sound between the "by pass...Gundo ?) and the Fister ...(opening the "sealed" opening"?
The only muffler shop here I "trust" wants $350 to $450 to do the "by pass" (want's to see how long it takes)
I also did the Fister mod. Great sound that's quiet at idle (once warm) with deep throaty sound accelerating. It costs more, yes, but the results are great. My mufflers also had some cracking so those were repaired at the same time.
Thanks for the feedback. I'm looking at whats best suited for my Fisters without losing power or torque. I'm looking to increase performance and sound as a secondary but I'm not sure if I should go with or without cats on x-pipe or crossovers.
I found a small mom and pop shop where the guy would listen to me and look at pictures I supplied from this forum, put my car on a lift and did it all for $150. The tail pipes weren't quite right so he put it back up in the air and got them adjusted to same heights. He wanted to charge me $140, but I splurged and gave him $150 for going the extra mile. I didn't have to do anything but touch ATM buttons.
@dak911
First photo below shows actual the 996 muffler with the Fister cross-pipe.
There are a few versions of the welded in inlet/outlet cross pipe. Fister locates and TIG welds the cross-pipe on the engine side of the muffler just above the mounting bracket and many local shops locate it on outside/bumper cover side of the muffler and MIG weld it. Locating it on the bumper cover side places the cross pipe very close to the bumper cover (heat) however there is insulation inside the bumper cover.
The Fister design and welding is clearly the least visible and best, however the mod is not visible outside the car so perhaps it does not matter.
This exactly correct. The gundo (PSE style) is what I have and you can barely notice the difference with the stock exhaust. I have serious doubts about that theory that says that just welding the third pipe, you make the muffler sound like the PSE. I think the PSE must have different piping inside the muffler to bring the gas to that additional outlet. Did anyone ever open a PSE muffler and a regular muffler to see the differences? Any video comparing a stock PSE sound with a Gundo hack mod?
The Fister mod, is a bypass and obviously it sounds louder, I dont like it too much tough (just personal taste here). I like the sound of the factory PSE (what the gundo hack, I think doesnt approach)
The problem with the attached videos, is that the one with the Gundo mod (PSE style) has also a XPIPE, so you can not say if the sound is because of that.
Has anyone ever done any before and after dyno testing to see if there really is any power gain/loss? I'm not sure how you would have a drop in low end torque just by bypassing some exhaust gasses? I'll be doing this in the next week or so.
Kyle
I jusr recently did the muffler delete and am still on the fence as to whether or not there is low end torque loss. Fabspeed claims gains, not losses, but there are a number of people who claim loss.
