True Duals vs. 2-1-2
Ultimate HDF Member
Joined: Mar 2012
Posts: 6,129
Likes: 143
From: Santa Cruz
Lots of folks like the sound and/or look of true duals but a good 2-1-2 will outperform a good true dual set-up on a bagger. Hell a stock non-cat '09 header will outperform a good true dual set-up on a bagger.
Extreme HDF Member
Joined: Sep 2010
Posts: 14,744
Likes: 402
From: Phoenix '53, '88, '09 Big Twins
a.) one of the advantages of a 2/1/2 set up is the large volume of the exhaust system.
the same twin cam A motor is used in the Touring and Dyna frames- the touring will always show about 3 horsepower more...the only diff is the exhaust system.
the large volume allows for high exhaust gas velocity
b.) another is that when the cylinders exhausts are connected as the exhaust gasses rush down the pipe, they form a low pressure zone behind them...this can "suck" the exhaust gasses out of the other cylinder faster.
which in turn can "suck" the intake charge of air and fuel into the cylinder faster- it is possible to get a more than 100% cylinder fill.
this is known as scavenging and it's effect is much dependent on cam profile
( this is why the v8 in the driveway has carefully designed headers and an "X" pipe by the transmission connecting the 2 cylinder banks...free power with out extra emissions or fuel consumption)
some riders prefer the sound of true duals, feel it gives better heat control or somehow has a "traditional look".
some of us with "traditional bikes" have the stock 2 into 1
mike
the same twin cam A motor is used in the Touring and Dyna frames- the touring will always show about 3 horsepower more...the only diff is the exhaust system.
the large volume allows for high exhaust gas velocity
b.) another is that when the cylinders exhausts are connected as the exhaust gasses rush down the pipe, they form a low pressure zone behind them...this can "suck" the exhaust gasses out of the other cylinder faster.
which in turn can "suck" the intake charge of air and fuel into the cylinder faster- it is possible to get a more than 100% cylinder fill.
this is known as scavenging and it's effect is much dependent on cam profile
( this is why the v8 in the driveway has carefully designed headers and an "X" pipe by the transmission connecting the 2 cylinder banks...free power with out extra emissions or fuel consumption)
some riders prefer the sound of true duals, feel it gives better heat control or somehow has a "traditional look".
some of us with "traditional bikes" have the stock 2 into 1
mike
Last edited by mkguitar; Sep 9, 2013 at 06:15 PM.
Grand HDF Member
Joined: Nov 2012
Posts: 3,784
Likes: 100
From: Pasadena TX
Subscribed. I have a stock head pipe, and hate the look. I believe there's a performance advantage in the 2-1-2, but in reality I'm not going racing and horsepower gains aren't as important to me as style is.
Advanced
Joined: May 2009
Posts: 63
Likes: 0
From: Joliet, Illinois
I went with the V&H Bagger Duals and the monster rounds on my '12 FLTRX. I am also running the SE255 cams. I am at 98 ft/lbs and 88HP with the Ventialtor (sp?) air filter on a 103" everything Ive seen shows that I am about 4HP down and about even on torque on other bikes with a 2-1 or 2-1-1.
Im good with the power where its at.
Im good with the power where its at.
Road Warrior
Joined: Mar 2006
Posts: 1,346
Likes: 3
From: Texarkana, TX
I had used either Rinehart true duals or Vance & Hines dresser duals on my touring bikes for years, but I went with a set of the Vance & Hines power duals on my new 2014 Limited and I've been really impressed. They give more power by having the crossover chamber, but retain a lot of the look of true duals and still sound like true duals.
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Road Warrior
Joined: Feb 2013
Posts: 1,625
Likes: 123
From: Meridian, Idaho
I have the Vance & Hines Power Duals Head Pipes and Vance & Hines High Flo mufflers. Compared to stock ... ya big difference.
Power Duals is the ticket to style, quality and performance
More than just individual head pipes, Power Duals integrates an exclusive Vance & Hines Power Chamber hidden behind a contoured heat shield that generates more horsepower and torque than stock
This new right side design eliminates the heat issues on the left side for the passenger, routing hot exhaust gases below the footpeg and protecting vital engine components and side covers from heat damage
Allows the use of any many muffler options
Made in the U.S.A.!!!
Plus they look damn cool IMHO
Power Duals is the ticket to style, quality and performance
More than just individual head pipes, Power Duals integrates an exclusive Vance & Hines Power Chamber hidden behind a contoured heat shield that generates more horsepower and torque than stock
This new right side design eliminates the heat issues on the left side for the passenger, routing hot exhaust gases below the footpeg and protecting vital engine components and side covers from heat damage
Allows the use of any many muffler options
Made in the U.S.A.!!!
Plus they look damn cool IMHO
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