18 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHFister Mod Complete
Leading reported evidence
Use 1.75" diameter bypass pipe
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
I used 1.75" diameter bypass pipe because that is what Fister uses.
Leading evidence: 'Use 1.75" diameter bypass pipe' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'lot louder' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Run will verify' (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.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed · Original poster
The shop that did the mod used 2" stainless, and they state that stainless gives a deeper sound.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that suspect a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
18 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261027T000231Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
I had my local Indy do their version of the Fister mod. This has been a bit of a chore. I originally took it over to a very reputable muffler shop in town. He had it for a week and finally called me and said he wasn't comfortable doing the job and to come back and pick up my mufflers. My friend has his 997 worked on with this Indy shop so I asked them if they do this mod. They said they prefer the Gundo style over the Fister style, but have done both. The apex on the bypass tube is pretty close to the inner fender. Hopefully I won't melt my rear fender. Anyway, installed them and took it for a drive tonight. My impressions are, these are louder than F&@k at WOT. Nice throaty sound in the mid range, and still pretty loud. The shop that did the mod used 2" stainless, and they state that stainless gives a deeper sound. I haven't noticed any difference in power plus or minus. I'll post an update after I've driven it for a week or so.
Kyle
I just had a local shop TIG weld 1.75" stainless bypass pipes on my mine. I am very pleased with the sound and the quality of the work. Fister is the way to go if you don't have a local shop to perform the work.
I wish my shop had done mine like that with a little less curve. They stated they needed all that curve to fit a 2" tube in there. Probably a lot louder with the 2" tube vs. a 1.75" tube? Do you think that .25" would make a big difference in sound?
Kyle
I just took it out again for a 20 minute drive. Mostly normal driving, and a little spirited driving. When the vario cam hits, it sure creates an increase in sound. Almost like a turbo kicking in. When I got back, I took some temp readings with my laser reader. Temp at the stainless tube was 250 F - 216 F. Outer rear fender temp reading was 109 F to 102 F. I'm not sure what temp one would need to start deforming the plastic bumper. I would think it would have to be > 400 F? This is sure a lot louder than I had expected.
Kyle
In my research, I read there is little to no sound difference between 1.75" and 2". I used 1.75" diameter bypass pipe because that is what Fister uses. Fister is the way to go if you do not have access to an local excellent shop to do the work.
They charged me $300. When I had asked why they had such a large radius they claim the radius bend allows more exhaust gases to bypass the muffler as opposed to a straight tube design. They also claim a slight performance improvement with the radius design as well. Only a dyno run will verify. This is the way they do the Fister style mod. I'm going to call the shop on Monday to ask about any concerns with the bend being so close to the inner rear fender. I drove it around again for about an hour in 95 degree temps, some high RPM driving. My temp readings on the exterior of the fender reads 136 F at the highest measured reading. So, I'm not too concerned yet.
I did remove the mufflers my self. An air ratchet sure makes the job easier getting the three nuts off the mounting bracket.
Kyle
Fister design is 1.75" and fairly straight. Fister is the way to go @ $450 plus round trip shipping. The quality of the work is very good. The ceramic coating is additional cost.
Good observation. I've been driving it a lot. Starting to get more familiar with the different sounds. As strange is it may sound, it sure seems to be louder until the engine gets to temp. I thought this was just in my head. I have verified this every time I've driven it. I can't see any reason why other than over fueling when the engine is warming up. It does sound quieter after the motor gets to temp. Probably in my head though. Its got a nice deep growl at the first tap of the throttle, then gets less deep as the throttle increases. The sound between 4000 RPM and 6800 RPM is intoxicating. What a symphony of sound especially at WOT. I thought nothing sounded better than a nice throaty V8. I think this is far better sounding. I guess the only thing I'm mildly disappointed in is the sound between 1000 RPM and 3000 RPM. Has a bit of a fart can sound. Not bad, and I'm sure I'll get used to it. I don't do much driving in this range anyway.
Kyle
I have Fisters, 200-cell cats, an IPD plenum, and my shop rag version of the orange cap mod. My combination is still very streetable as long as I'm easy on the throttle, but it howls like a banshee at WOT.
I hope you decide you like the finished goods - but if you decide you hate the mufflers, you won't have any trouble selling your pre-Fistered cans.
This is a source reference. Confirm exact model applicability in the original material.
