Why "true duals"
Tourer
Joined: Feb 2012
Posts: 303
Likes: 0
From: ontario, Canada
Put the full sac conversion on my 05 and noticed no loss of power or torque, and the sound is perfect with a set of 3.5" rineharts .... IMO 
Last edited by ShadowMonster; May 30, 2013 at 07:55 PM.
Tourer
Joined: Feb 2012
Posts: 303
Likes: 0
From: ontario, Canada
I think the performance discussion on a Massey Ferguson technology Vtwin is just funny anyway, no offence to anyone who has spent thousands trying to get a few more HP out of heavy touring HOG, perhaps you've purchased the wrong bike.........
Last edited by ShadowMonster; May 30, 2013 at 08:21 PM.
Extreme HDF Member
Joined: Sep 2010
Posts: 14,744
Likes: 402
From: Phoenix '53, '88, '09 Big Twins
Well if I had to explain...
When dealing with the barge that is the modern touring Harley pipe changes can very much alter the torque response of the motor.
That torque is what gets the bike moving from a stop--- so important to us.
I won't comment on the looks or sound, beyond my opinion that true duals are a fairly recent fashion statement and loud pipes just say "lookit me"
in general:
true duals reduce torque compared to a system where the 2 exhaust headers are connected
2 into 1 increases torque compared to a system where the 2 exhaust headers are connected
however the large volume of the stock type system may increase horsepower- a look at a spec sheet for a Dyna model may show reduced power numbers compared to the same motor, same gearing for a touring model- the larger touring model can better accomodate a large volume exhaust system
The old 2/1/2 evo style header ( to 08) with the Y pipe was good to 100 HP
and the new style 2/1/2 ( 09+) should have potential for more- especially if the flow is not hindered by a cat.
the stock motor is less than 70 HP, stage 1 will take that near 80 HP
cams maybe to 90
add headwork maybe 100.
The reason that true duals tend to result in reduced performance is that the scavenging effect can only take place if the cylinders are connected- it does not matter if the individual headers are stepped, have 'cones, or other mysterious majik...scavenging needs the cylinders connected.
that is why every v8 in the driveway has the exhaust headers connected...and an X pipe under tranny to connect the 2 sides
That is free power, with no expense, loss in economy or stress on the motor
when it comes to straight pipes ( no muffler)- these pipes DO make better horsepower ... but at 6000 rpm.
since most of our riding is at sub 3000 rpm, we want torque
( and for those who need it, Massey Ferguson is an agricultural equipment manufacturer...substitute "John Deere")
mike
When dealing with the barge that is the modern touring Harley pipe changes can very much alter the torque response of the motor.
That torque is what gets the bike moving from a stop--- so important to us.
I won't comment on the looks or sound, beyond my opinion that true duals are a fairly recent fashion statement and loud pipes just say "lookit me"
in general:
true duals reduce torque compared to a system where the 2 exhaust headers are connected
2 into 1 increases torque compared to a system where the 2 exhaust headers are connected
however the large volume of the stock type system may increase horsepower- a look at a spec sheet for a Dyna model may show reduced power numbers compared to the same motor, same gearing for a touring model- the larger touring model can better accomodate a large volume exhaust system
The old 2/1/2 evo style header ( to 08) with the Y pipe was good to 100 HP
and the new style 2/1/2 ( 09+) should have potential for more- especially if the flow is not hindered by a cat.
the stock motor is less than 70 HP, stage 1 will take that near 80 HP
cams maybe to 90
add headwork maybe 100.
The reason that true duals tend to result in reduced performance is that the scavenging effect can only take place if the cylinders are connected- it does not matter if the individual headers are stepped, have 'cones, or other mysterious majik...scavenging needs the cylinders connected.
that is why every v8 in the driveway has the exhaust headers connected...and an X pipe under tranny to connect the 2 sides
That is free power, with no expense, loss in economy or stress on the motor
when it comes to straight pipes ( no muffler)- these pipes DO make better horsepower ... but at 6000 rpm.
since most of our riding is at sub 3000 rpm, we want torque
( and for those who need it, Massey Ferguson is an agricultural equipment manufacturer...substitute "John Deere")
mike
Last edited by mkguitar; May 31, 2013 at 01:27 AM.
Big Kahuna HDF Member
Joined: Mar 2010
Posts: 32,562
Likes: 2,577
From: Shit Weather USA
Not all true duals are the same. Rinehart and MGS use a stepped system,and I believe Freedom does too.
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Outstanding HDF Member
Joined: Jan 2007
Posts: 2,598
Likes: 19
From: Naples FL / Pine TWP PA
Really? Pretty easy to double the factory HP on these motors.