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Discussion Starter #1 (Edited)
So I was reading an article in Motor Trend where they were talking about a new exhaust technology, polyphonic pipes. Basically they insert a set of pipes that amplifies good sounds and dampens bad ones.

Borla is working on it for the aftermarket, but a few new cars come with it, one of which is the Challenger R/T! They said it’s right after the x-pipe, would be cool to see it.

So for all the people saying there’s something great about the sound of the new R/Ts, there is a new exclusive feature!
 

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They do sound really good, now I know why.
 

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I freaking knew it! My 2018 R/T Plus sounds better than my Scat Pack did. Hal mentioned he heard from an insider that Dodge did something special with the 5.7 R/T exhaust and this must be it. Nice find.

Now, something else I noticed was that in MOPAR Action Magazine (or MOPAR Muscle) they reported dyno testing from a MOPAR show where I noticed a bone stock '17 R/T with the new system threw down better numbers than a '14 or '13 R/t did with bolt on mods and a tune... Hmmmmmm. I'll have to go back and look to confirm. Wondering if hp went up a touch with the '17+ 5.7 cars but Dodge didn't advertise it.
 

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The RT uses the same exhaust manifolds (log type...no collector region) of the previous years but similar mid and catback of the 2.75" AES of the scats.
 

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The RT uses the same exhaust manifolds (log type...no collector region) of the previous years but similar mid and catback of the 2.75" AES of the scats.
Similar to the Scats and SRTs but with a little extra. I had originally thought it was the exact same system (makes sense from a cost perspective ) but it's tweaked a little bit for better sound.
 

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Similar to the Scats and SRTs but with a little extra. I had originally thought it was the exact same system (makes sense from a cost perspective ) but it's tweaked a little bit for better sound.
So where is the difference? Where are polyphonic pipes on the stock exhaust.
https://www.moparpartsgiant.com/parts-list/2017-dodge-challenger/exhaust-exhaust-system.html?Diagram=i2359393

If you scroll down, it shows 2017 RT sharing the same exhaust as SP.
https://www.moparamerica.com/oem-parts/mopar-muffler-and-pipe-5181886al/?c=aT1VUDA4MjA3NSZyPWxheWVyXzY=

If it is true, I would expect to see something like this in the system.
https://www.borla.com/products/polyphonic-exhaust-technology/
 

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So where is the difference? Where are polyphonic pipes on the stock exhaust.
https://www.moparpartsgiant.com/parts-list/2017-dodge-challenger/exhaust-exhaust-system.html?Diagram=i2359393

If you scroll down, it shows 2017 RT sharing the same exhaust as SP.
https://www.moparamerica.com/oem-parts/mopar-muffler-and-pipe-5181886al/?c=aT1VUDA4MjA3NSZyPWxheWVyXzY=

If it is true, I would expect to see something like this in the system.
https://www.borla.com/products/polyphonic-exhaust-technology/
I have no idea where in the system that they incorporated that technology. I know Hal posted on an earlier thread, where other owners who had gone from Scat Pack to a '17+ R/T 5.7 and commented on the louder sound, that someone from Dodge explained to him they intentionally tweaked the 5.7's exhaust for better sound over the SRT system. That's all I know. That, and I can tell from owning a few Scat Packs now and having gone back to '18 5.7 R/t. It's noticeably louder and nastier than a Scat Pack.

I would assume the mids and cat section for the 5.7 is different than the SRT system since the 5.7 uses the log manifolds vs the shorty headers in the SRT. I know with the older 5.7 system you needed SRT mids if you wanted to upgrade to the SRT shorties.
 

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I have no idea where in the system that they incorporated that technology. I know Hal posted on an earlier thread, where other owners who had gone from Scat Pack to a '17+ R/T 5.7 and commented on the louder sound, that someone from Dodge explained to him they intentionally tweaked the 5.7's exhaust for better sound over the SRT system. That's all I know. That, and I can tell from owning a few Scat Packs now and having gone back to '18 5.7 R/t. It's noticeably louder and nastier than a Scat Pack.

I would assume the mids and cat section for the 5.7 is different than the SRT system since the 5.7 uses the log manifolds vs the shorty headers in the SRT. I know with the older 5.7 system you needed SRT mids if you wanted to upgrade to the SRT shorties.
That is because the 2017 R/T 5.7 uses the same exhaust as the SP. Look at my previous links posted above.


Not sure why 2018 RT is not listed though. The polyphonic pipes would have to be inserted at a straight section of pipe. The borla system essentially removes the mid mufflers which WILL make the exhaust much louder.


Polyphonic pipe on a 2019 5.7 (click on the play button):banana:
 

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my question, of course I need to hear a 2018 R/T exhaust first but. can the newer exhaust be put on a 2015 and just delete the Active Exhaust? Of course I changes my mufflers and deleted the resonators, but if it sounds better than what I did, might be neat to do it.
 

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That is because the 2017 R/T 5.7 uses the same exhaust as the SP. Look at my previous links posted above.


Not sure why 2018 RT is not listed though. The polyphonic pipes would have to be inserted at a straight section of pipe. The borla system essentially removes the mid mufflers which WILL make the exhaust much louder.


Polyphonic pipe on a 2019 5.7 (click on the play button):banana:
It's not that I didn't know that the '17+ 5.7 had an active exhaust system, I knew that. I also had two 5.7s years ago with the older system that your car came with. I saw your links, they only point out that those parts will "fit". They also mention the 6.1 Hemi in one place too. The shorty header manifold will "fit" the 5.7, 6.1, 6.4, and the Hellcat 6.2 too... Perhaps Hal will jump in here to clarify. My understanding is that the active exhaust for the 5.7 cars is not identical to the 6.4 cars. Heck, even the Hellcat's active system is different between the auto and manual.
 

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my question, of course I need to hear a 2018 R/T exhaust first but. can the newer exhaust be put on a 2015 and just delete the Active Exhaust? Of course I changes my mufflers and deleted the resonators, but if it sounds better than what I did, might be neat to do it.
If you can bypass the valves or get them to lock open you could. I was surprised how loud it was for a stock system. I went from a 6.4 manual Scat Pack to the 5.7 manual R/T Plus and I could tell the second I started driving for my first test drive that the car was louder than the one I drove to the dealership with. The noise inside the cabin is intoxicating. Has this pure growl sound under throttle.
 

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It's not that I didn't know that the '17+ 5.7 had an active exhaust system, I knew that. I also had two 5.7s years ago with the older system that your car came with. I saw your links, they only point out that those parts will "fit". They also mention the 6.1 Hemi in one place too. The shorty header manifold will "fit" the 5.7, 6.1, 6.4, and the Hellcat 6.2 too... Perhaps Hal will jump in here to clarify. My understanding is that the active exhaust for the 5.7 cars is not identical to the 6.4 cars. Heck, even the Hellcat's active system is different between the auto and manual.
What I am trying to show is the reason why the 2017+ 5.7 sounds louder/meaner is because they run a larger 2.75" cat back and the resonator is a straight thru design...similar (the 2017 parts catalog suggests the exhaust systems are identical) to the SP/SRT. The active exhaust valve, has little to nothing to do with the tone. It is there to quiet down the exhaust under certain conditions. I highly doubt the "polyphonic" technology has anything to do with this except that if dodge did implement on 2018 models, then the tone of the exhaust would be louder because the mid mufflers would have been replaced with the polyphonic device, which appears to alter the pitch of the exhaust tone (I would like to hear a system with and without this device as I think it is a pipe dream). The reason the auto and manual exhausts are different is due to MDS, at least on the earlier non-AES models.
 

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The portion of the MT article the OP posted says the Borla polyphonic pipes are ' available ' for Challenger R/T and the other models listed. where does it say they are factory installed ? Did I miss that part ?
 

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From the first picture, it looks like an open merge collector that they build good race headers with. If you welded the openings shut, you'd have a merge setup.

The most popular one is made by Burns. There is quite a bit of science behind them too. Pretty interesting stuff and Thanks for the post/info. :cheers:
 

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What I am trying to show is the reason why the 2017+ 5.7 sounds louder/meaner is because they run a larger 2.75" cat back and the resonator is a straight thru design...similar (the 2017 parts catalog suggests the exhaust systems are identical) to the SP/SRT. The active exhaust valve, has little to nothing to do with the tone. It is there to quiet down the exhaust under certain conditions. I highly doubt the "polyphonic" technology has anything to do with this except that if dodge did implement on 2018 models, then the tone of the exhaust would be louder because the mid mufflers would have been replaced with the polyphonic device, which appears to alter the pitch of the exhaust tone (I would like to hear a system with and without this device as I think it is a pipe dream). The reason the auto and manual exhausts are different is due to MDS, at least on the earlier non-AES models.
I'm not trying to argue, I think this is a classic case of misinterpretation of written word. I'm simply confirming that the '17+ 5.7 system is louder than the Scat Pack/SRT active system and that Hal (moderator on this forum) had mentioned that someone from Dodge said they intentionally did something different to the 5.7's active system to make it sound louder/better than the Scat Pack's system. I don't know what that is so I was thinking it could be this... But on a second read it does seem that the article is referring to Borla's technology being available for the R/T. So... It's still unknown what Dodge did differently with the 5.7 active system vs the 6.4's active system.
 

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I'm not trying to argue, I think this is a classic case of misinterpretation of written word. I'm simply confirming that the '17+ 5.7 system is louder than the Scat Pack/SRT active system and that Hal (moderator on this forum) had mentioned that someone from Dodge said they intentionally did something different to the 5.7's active system to make it sound louder/better than the Scat Pack's system. I don't know what that is so I was thinking it could be this... But on a second read it does seem that the article is referring to Borla's technology being available for the R/T. So... It's still unknown what Dodge did differently with the 5.7 active system vs the 6.4's active system.

My bad, I did't mean to come off as arguing. I should have just said I don't think the polyphonic pipes were used and left it at that. But I did find that the 2017 RT and SP do use different exhaust mufflers/resos (the online parts catalog I looked at was wrong). :domotwak:

2017 RT


2017 SP
 

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my question, of course I need to hear a 2018 R/T exhaust first but. can the newer exhaust be put on a 2015 and just delete the Active Exhaust? Of course I changes my mufflers and deleted the resonators, but if it sounds better than what I did, might be neat to do it.
If you can bypass the valves or get them to lock open you could. I was surprised how loud it was for a stock system. I went from a 6.4 manual Scat Pack to the 5.7 manual R/T Plus and I could tell the second I started driving for my first test drive that the car was louder than the one I drove to the dealership with. The noise inside the cabin is intoxicating. Has this pure growl sound under throttle.
Is the cold start louder as well?
 

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The cold start is louder. I had a 2016 R/T manual and a 2017 R/T Shaker auto and I now have a 2018 5.7 T/A auto. Both the 2017 and 2018 have active exhaust and are a lot louder than the 2016. I don't know if there is any difference between the 2017 and 2018 systems, but my T/A seems louder than the Shaker was. The systems may be the same, but just the difference between cars. I love driving the T/A, it sounds really good in the car. It has that deep growl that you would expect from a muscle car.
 

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