SOUL | 997 GT3 Side Muffler Bypass vs Center Muffler Bypass Explained
#16
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I have a question. I k ow you offer the side muffler deletes with and without the valves.
I imagine there is a reason why Porsche put the valves in there in the first place...torque at lower rpm. Am I wrong? I'm surprised this point doesn't come up more when people discuss deleting side pipes or simply unplugging the valve units.
Ty
I imagine there is a reason why Porsche put the valves in there in the first place...torque at lower rpm. Am I wrong? I'm surprised this point doesn't come up more when people discuss deleting side pipes or simply unplugging the valve units.
Ty
Apologies for the late response, I didn't get my Rennlist notification like I normally do. I have had no customers of mine ever complain of torque loss from a center or side delete, most provide feedback of seat of the pants improvement but I am more inclined to say that is due to saving 35lbs off the back of the car from ditching those side mufflers. That said, to give you a little background... it is our belief (along with many others) that Porsche did not design these three mufflers with valves with the primary goal of performance. If Porsche was having the exhaust system manufactured to maximize performance with no other variables involved, you would be running a Cup/RSR exhaust system on your street car and even those are generally manufactured in different ways to meet sound regulations at different tracks. They would have also taken the time to tweak and change the design over the years and various engine configurations, however these mufflers have remained unchanged in design from Porsche from 2007 to 2019 across the 997.1 to 991.2 GT3/RS. These initial 997.1 systems have been made to fit different generations by simply lengthening the tip assemblies that bolt onto the center muffler. Porsche has strict sound restriction in Europe that they have to meet, along with expected comfort levels in cabin of the majority of their target market. Factory PSE programming overrides whether or not the Sport/PSE button is pushed at lower rpms, most likely due to the need of keeping sound levels down around residential areas. The valves then open under heavy load as you crest into higher rpms, we believe in order to reduce pressure and heat in the exhaust system under track conditions. At the end of the day, unless you track down the exhaust manufacturer for Porsche and talk to their development team members back in the mid 2000s you are never going to get the exact and conclusive reasoning behind the design. That said, what I've said is the most logical and educated reasoning I have determined with various resources in the industry over the years.
Best regards,
John Gaydos
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SOUL PERFORMANCE PRODUCTS
Quality Exhaust Solutions, Fair Pricing, and Outstanding Service
John Gaydos- Owner, Performance Specialist
Cell - (484) 883-6197
johng@soulpp.com
Jon Wheel - Marketing Manager
jwheel@soulpp.com
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#17
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Daniel puts a lot of work into ensuring that our Side Muffler Bypass Pipes are well made with smooth transitions and proper, back purged welds. You'll appreciate the quality and enjoy the sound for life with our Lifetime Warranty for both street and track use!
![](https://soulpp.com/wp-content/uploads/2020/07/Soul-Performance-Products-Porsche-GT3-Valved-Side-Muffler-Bypass-Pipes-Fabrication-4.jpg)
-Mike
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-Mike
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Delete, wrong forum.
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I run the soul side bypass pipes along with an RSS X pipe center delete. Sound is insane... I can also highly recommend buying any soul product and their customer service is probably the best that I have ever experienced.
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Soul Performance (08-21-2020)
#22
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Yes! Would love to hear / watch videos of the Side Muffler Bypass Vs. the Centre Muffler Bypass.
P.s. John - I sold the 2nd Spyder and the Carrera T and jumped into a 7.2 RS. Snap! Joel
P.s. John - I sold the 2nd Spyder and the Carrera T and jumped into a 7.2 RS. Snap! Joel
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Regards,
John Gaydos
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Once i source the balance of a stock system, i plan to order Soul Valved side bypass pipes and happy to make a video....Just wish the turnaround time wasn't so long
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-Mike
#26
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Why would you install a valved SMD if your CMD is done? I don’t see how that would make much difference with valve open vs closed...why not just put like Akrapovic Link Pipes instead of SMD? I have a sharkwerks CMD currently and I love it 5 k rpm and above, under that rpm range it is to quiet for me. I’m a loud attn needing ***** , lol. I just love the GT3 flat scream, and I want that same sound under 5k rpm range as well. What is my best bet to achieve this ?
#27
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^^ Any center delete and unplug your values to get the same effect under 4.5k rpm
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I have the Carnewal remote valve controller, soul valved side deletes and M&M/FVD center delete. Closing the valves does quiet down a bit leaving the house. Valves open and it sounds fantastic ![thumbup](https://rennlist.com/forums/graemlins/thumbup.gif)
I can speak on the phone/bluetooth, and I do close the valves around cops and have had no issues-
There are a few threads on these options if you search. M&M/FVD, Sharkwerks, Soul center bypass and a few others accept the OEM exhaust straps/clamps to hold down the system, others don't.
![thumbup](https://rennlist.com/forums/graemlins/thumbup.gif)
I can speak on the phone/bluetooth, and I do close the valves around cops and have had no issues-
There are a few threads on these options if you search. M&M/FVD, Sharkwerks, Soul center bypass and a few others accept the OEM exhaust straps/clamps to hold down the system, others don't.
#29
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Hello Mike, I know there's some weight savings and heat dissipation advantages, but what about performance gains (HP & TQ) from the SMD?
#30
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All, some additional feedback on a 997.2 GT3 with recently installed Soul valved side muffler bypass. Wasn't too hard to do at home, without a lift & with the rear bumper removed. After doing it, I wouldn't even attempt it without removing the bumper unless you have a lift. The only hassle I had was with the horrible deformed torque prevailing nuts that Porsche use on the side pipe to centre muffler joints, and that's nothing to do with the Soul kit. I've been modifying cars myself for 20 odd years and I have to say the quality of the Soul valved SMB's is brilliant. I was concerned, as I've never dealt with a fully hard mounted exhaust before, but the dimensional accuracy of the Soul parts was spot on.Now to the sound. I do have drone around 2500rpm, which I was surprised about given some prior comments indicating that there was no drone with the Soul SMB's, though I can't imagine any SMB from different companies being any better. I think it's just an inevitable downside when you ditch those huge standard side mufflers. It's not unlivable drone like I've had in modified Supra's before, but I would however still like to do a back to back vs other GT3's with different modified exhausts just to check. Drone aside, I can't overstate how amazing the thing sounds now above 3500rpm. It surprised me a bit actually as I thought that above 3500rpm once the valves are open on the stock exhaust and more or less bypassing the side mufflers that the sound would be more or less the same, but it isn't, it's much better. Unlike many on this forum that think Mezger's sounds amazing even in stock form, I don't, give me a GT350 Voodoo for sound any day of the week. Does the car sound as great as a Voodoo 5.2 now? No, but jeeze it's close. It's a completely different sound, but sounds like an exotic supercar above 3500rpm, and below 3500rpm when the closed side valves made it sound asthmatic with the stock exhaust, it now sounds like a proper performance car should.
For anyone like me that's spending a lot of time trying to decide on whether to go SMB or CMB, and which brand, all I can say is that having forked over what I consider to be a decent chunk of cash for the Soul SMB's, I would absolutely do the same again if I got a stock GT3 tomorrow.
For anyone like me that's spending a lot of time trying to decide on whether to go SMB or CMB, and which brand, all I can say is that having forked over what I consider to be a decent chunk of cash for the Soul SMB's, I would absolutely do the same again if I got a stock GT3 tomorrow.
The following 4 users liked this post by KPJ:
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