Real Difference in Duals

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Jul 30, 2018 | 02:22 PM

#21

harkon

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Joined: Jul 2015

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From: Calgary, Alberta

Quote:

Originally Posted by Max Headflow

Yeah you're right.. That one I don't have a direct comparison. This one is close. Lower power was a thunderheader compared to staggered duals. The staggered duals did have a small 1 inch cross over at the muffler. You got any runs to show otherwise?

I don't collect dyno sheets so no, I don't have any.

The thing about a dyno sheet like that is that you never really know what, how or why. Not saying it's not accurate, maybe ThunderHeader is ***** ... I dunno. As the runs are 16 minutes apart I'd say there was no tuning done with the change. Maybe a possibility that tuning is an issue, who knows? Maybe you're right. Maybe everything I've ever known about cylinder scavenging and exhaust collectors / crossovers is wrong. I dunno. I tend to trust the people who know and have followed proven tech.

Again, I have no dog in this hunt.

Jul 30, 2018 | 02:37 PM

#22

Max Headflow

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From: poway

Quote:

Originally Posted by harkon

While the time was close they were about 2 1/2 months apart. The thing is that you don't know what's going to work or not until you try it. I'll agree for the most part 2-1s work better on baggers simply due to how TDs are installed but I've seen some motors like staggered duals do better than 2 into 1s. Exhaust energy used for scavenging can be spread out more than just by the irregular firing pattern of the v twin and a 2 into 1.

Jul 30, 2018 | 03:16 PM

#23

harkon

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From: Calgary, Alberta

Alrighty then, I suppose there are exceptions to every rule.

Jul 30, 2018 | 07:44 PM

#24

DaleMc0622

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From: SC

Well, didn't this post get off track, lol. I am going to guess that "seat of the pants" I will not notice the loss of low end toque if there is any. I have the TTS tuner so I should be able to get it tuned pretty good. Thanks all, Duals on the way.

Jul 30, 2018 | 07:47 PM

#25

MURPHCC1

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From: Cape Cod

Quote:

Originally Posted by DaleMc0622

Is the loos of low end very noticeable or is it mostly seen on a Dyno. Most people have told me that "seat of the pants" difference is either barley noticeable if at all.

The BUTT dyno says it's real.......yes you can feel the difference.

Jul 31, 2018 | 12:07 PM

#26

harkon

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From: Calgary, Alberta

Quote:

Originally Posted by MURPHCC1

The BUTT dyno says it's real.......yes you can feel the difference.

I can share what I experienced. I went from a stock setup to Dresser Duals and a FuelPak ... later a PowerVision. I didn't notice much of anything. I did like the true dual sound better though. I was looking for a deeper tone and wanted more bottom to mid power. I went to the FM Super Duals and HiRoller mufflers. With the tune FM gave me, I noticed a good hit in the mid range right to the top. At lower revs it seemed to have more pulling power, but the hit in the mid was definitely noticeable. I put in the FM inserts and immediately noticed that mid range hit starts at almost off idle. The engine does seem to lay down a bit now when approaching the rev limiter, but I rarely get the engine revving that high. I'm happy with the setup. The tone is a booming bass that I love, but amazingly enough is still within legal limits. It's not really LOUD but is deep enough that heads turn. With all of the auto tuning and messing around with the true duals, I never could get the same power. It might be as well the change in mufflers, but I had the SE FatShotz which are known to be a pretty good power muffler. When I asked FM about their E0SAeries mufflers with that header or the HiRollers, they said the HiRollers would offer a deeper tone, but both would perform about on par. For me that little crossover made a world of difference.

Aug 3, 2018 | 06:47 AM

#27

DaleMc0622

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From: SC

Thanks for all the input guys, I was going to order the Fullsac conversion but they are back ordered so I ordered a set of Cobra True duals last night. Once they are on and the TTS adjustments are made I will post a short review. Thanks again and ride safe.

Aug 3, 2018 | 05:32 PM

#28

DaleMc0622

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From: SC

Okay guys, since I pulled the trigger on Cobra true Duals, and I knew that 2 into 1 would produce better torque and power but I like the sound of true duals and I had Cobra RPT's on my Super Glide and quality was great. I have a muffler question as follow up, I am currently running a set of Rinehart 3.5 inch slip ons and I also have a set of Screamin Eagle 3.5 mufflers. Anyone have any idea which ones will sound better and would one give better performance over the other?

Thanks