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Old May 14, 2012 | 01:26 PM
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Originally Posted by grbrown
To revise those words slightly: each cylinder on a stock system uses both mufflers. On a TD system each cylinder flows through only one muffler.
I understand all that. What has not been explained is why it's louder when the "sharing" no longer exists. It's the same combustion exiting from the same two slip-ons.
 
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Old May 14, 2012 | 01:38 PM
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Originally Posted by racklefratz
I understand all that. What has not been explained is why it's louder when the "sharing" no longer exists. It's the same combustion exiting from the same two slip-ons.
I can't remember exactly how it was explained to me but imagine it like this.... we know our engines are air pumps. So if you push air through one tube straight out, without any interference, it has a certain force. Imagine spitting a spitball out a straw. Now you take two pipes, connect them with a cross over, and create turbulence, you may create some backpressure, but the force coming out the end is lessened from that turbulence created with the crossover, if you took two straws, put a crossover and tried to spit out paper from each, it isn't going to come out with the same force. That force from the straight tube, and its increased pressure will increases volume. Its not going to increase it a whole lot because you still have mufflers toning it down. And losing some of that turbulence backrpessure is where some torque is lost. Thats why some people like the stepped headers... to help scavenge some pressure for torque.

Thats a paraphrased way it was explained to me... if I am wrong I apologize and hope someone can correct it. But it made sense when I heard it..LOL
 
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Old May 14, 2012 | 02:47 PM
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Originally Posted by racklefratz
I understand all that. What has not been explained is why it's louder when the "sharing" no longer exists. It's the same combustion exiting from the same two slip-ons.
No it's not! With the stock system both mufflers work on each cylinder. The front and rear pipes join together, then divide so the exhaust goes out of both mufflers.

With TDs each cylinder uses only one muffler, not both. The pipes do not join.
 
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Old May 14, 2012 | 03:11 PM
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Originally Posted by grbrown
No it's not! With the stock system both mufflers work on each cylinder. The front and rear pipes join together, then divide so the exhaust goes out of both mufflers.

With TDs each cylinder uses only one muffler, not both. The pipes do not join.
I already said I understand all that. I've owned both types.

I also said "It's the same combustion exiting from the same two slip-ons" and you say "No, it's not". You're wrong. It is precisely the same 2 cylinders dumping the same exhaust into the same 2 slip-ons. The only difference is the head pipes.

Simply repeating the plumbing differences between these 2 types of exhaust systems fails to address what acoustical properties make true duals louder, if in fact, they are.
 
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Old May 14, 2012 | 04:10 PM
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Something is getting lost in translation. When the exhaust from one cylinder goes out through two mufflers it doesn't make as much noise as when the same exhaust goes out through only one muffler.
 
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Old May 14, 2012 | 05:26 PM
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Originally Posted by grbrown
Something is getting lost in translation. When the exhaust from one cylinder goes out through two mufflers it doesn't make as much noise as when the same exhaust goes out through only one muffler.
Starting to understand now. Thanks.

I'm such a purist that I still prefer the TD route, noisier though it may be.
 
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Old May 14, 2012 | 06:53 PM
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The sound coming from tru-duals is pure HD essence It's all about the sound not the volume
 
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Old May 14, 2012 | 08:26 PM
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Yep, and after I get my chrome rims my next mod will be true duals. I love the "potato potato" sound.
 
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Old May 14, 2012 | 08:30 PM
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Full length 3" duals - stepped headers
 
Last edited by 131tman; May 14, 2012 at 08:50 PM.
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Old May 14, 2012 | 09:52 PM
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Originally Posted by Armstronges
Should installing duals make a big difference in exhaust volume when using the same slip ons that was used on stock head pipe? How bout running temp. I just installed a set on my 09 sg and the exhaust is way louder and seems to be hotter. I know.....probably a dumb question but keep in mind I'm a previous wing owner and didn't deal with exhaust. Only fancy lights and gizmos
Yes, installing TD's like I did over the winter made the bike considerably louder. However, at the same time I got cams and a Stage 1 air cleaner put on also. People tell me that those two things will also ad to the volume. I have spent enough on her this season but next winter I have decided on trying Nightsticks or Fatshotz to see how much I can drop the noise without hurting the performance. I think they are made by Supertrapp.
 
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