Softail Models Standard, Custom, Night Train, Deuce, Springer, Heritage, Fatboy, Deluxe, Rocker and Cross Bones.
Sponsored by:
Sponsored by:

power differences between 2-1 pipes vs. duals

Thread Tools
 
Search this Thread
 
  #11  
Old 08-21-2008, 09:39 AM
128auto's Avatar
128auto
128auto is offline
Extreme HDF Member
Join Date: Sep 2006
Location: Vancouver B.C. Canada
Posts: 10,117
Received 29 Likes on 26 Posts
Default

To be honest, I bought this 2 into 1 big radius 70% for look and 30% for sound and performance, fair enough?
 
  #12  
Old 08-21-2008, 03:56 PM
KumaRide's Avatar
KumaRide
KumaRide is offline
Elite HDF Member
Join Date: May 2008
Location: Newcastle, Ca.
Posts: 4,620
Received 187 Likes on 148 Posts
Default

Originally Posted by Tin Gizel

I'm getting really sick of seeing V&H everywhere, to each their own.
Are you sick of these?? lol jk
 
  #13  
Old 08-21-2008, 05:48 PM
Herr Monk's Avatar
Herr Monk
Herr Monk is offline
Elite HDF Member
Join Date: Sep 2007
Location: Nuevo México, Los Estados Unidos de América
Posts: 4,541
Likes: 0
Received 1 Like on 1 Post
Default

...ummm some interesting answers...

Okay... an exhaust pipes have one function... to take the exhaust away from the engine... the quicker they do it, the more power you make... it's about exhaust velocity, plain and simple... higher velocity = more power.

The ideal exhaust will give you the highest possible exhaust velocity for a given RPM... to do that, you'd have to have a self-adjusting exhaust... but you can get close without one.

There are a few factors that play into the velocity, there is savaging from all the vibrating and bouncing going on, there is diameter, there are baffles... you'll notice even you sock pipes have that crossover... that's to equalize cylinder pressure... that's important. True duals don't do that.

Think about water, and how, given a certain pressure, how you would speed up or slow down the velocity... too large a pipe on a small engine will have a low-velocity... too small a pipe on a large engine will get clogged, and also have a low velocity.

What a 2>1 does is function as a collector that almost acts "self-adjusting" or it gives the a similar effect... 2-2s are not bad... but depending on diameter, length, e& they basically have a very narrow band in which they are anywhere close to ideal.

2>1s have a larger one.

Short drag pipes are fine for WOT, but won't make much power anywhere else... the exhaust velocity drops way down... that tends to be true of many 2-2 pipes, so what people do is put baffles and torque cones in... they just restrict air flow, which is antithetical to making power... these too slow down exhaust velocity... but they make the bike more "streetable" by basically de-tuning the engine to run with a clogged pipe...

It's a Harley, it's really about looks, but you will have a much nicer power-band going with a good 2>1...
 
  #14  
Old 08-21-2008, 06:05 PM
rheron's Avatar
rheron
rheron is offline
6th Gear
Join Date: Nov 2007
Posts: 10
Likes: 0
Received 0 Likes on 0 Posts
Default HP drop with duals...

Okay, just finished two "true dual" installs on identical bikes with wildly different results (both bikes were 08 Deluxes)

- first install: the samson longs (S2-431), PCIII, HD stage1, custom dyno tuned map.
- second install: V&H true duals (stock endcaps), PCIII, Ness big sucker, canned map from Fuel Moto.

Samson pros: look tougher, continuous diameter all the way back, deeper rumble, fishtails look more "nostalgic".

Samson cons: pipes blue (no issue with heat shields so its pretty much invisible), install much more complicated than the V&H due to custom seat bracket to allow the rear pipe to come left (otherwise fit fine), also access to the rear lower head bolt is "challenging".

V&H pros: no blueing whatsoever, better power, louder idle but higher pitch with std baffles,
piece cake install due to the squished rear head tube (lots of space compare to the "honeymoon fit" on the samson.

V&H cons: short pipes dont look as good, rear pipe (left) a little closer to your leg (heat).

Summary: with the V&H combo, power is much better than stock (samson is also better but the V&H kicks ...). For looks go with Samson (otherwise I'd choose V&H... very hard to be disappointed with this install)...

Hope it helps,

Ralph-
 
  #15  
Old 08-21-2008, 07:33 PM
SuperAhcmed's Avatar
SuperAhcmed
SuperAhcmed is offline
Banned
Join Date: Jul 2006
Posts: 643
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Herr Monk
...ummm some interesting answers...

Okay... an exhaust pipes have one function... to take the exhaust away from the engine... the quicker they do it, the more power you make... it's about exhaust velocity, plain and simple... higher velocity = more power.

The ideal exhaust will give you the highest possible exhaust velocity for a given RPM... to do that, you'd have to have a self-adjusting exhaust... but you can get close without one.

There are a few factors that play into the velocity, there is savaging from all the vibrating and bouncing going on, there is diameter, there are baffles... you'll notice even you sock pipes have that crossover... that's to equalize cylinder pressure... that's important. True duals don't do that.

Think about water, and how, given a certain pressure, how you would speed up or slow down the velocity... too large a pipe on a small engine will have a low-velocity... too small a pipe on a large engine will get clogged, and also have a low velocity.

What a 2>1 does is function as a collector that almost acts "self-adjusting" or it gives the a similar effect... 2-2s are not bad... but depending on diameter, length, e& they basically have a very narrow band in which they are anywhere close to ideal.

2>1s have a larger one.

Short drag pipes are fine for WOT, but won't make much power anywhere else... the exhaust velocity drops way down... that tends to be true of many 2-2 pipes, so what people do is put baffles and torque cones in... they just restrict air flow, which is antithetical to making power... these too slow down exhaust velocity... but they make the bike more "streetable" by basically de-tuning the engine to run with a clogged pipe...

It's a Harley, it's really about looks, but you will have a much nicer power-band going with a good 2>1...
2-1's and pipes with a "crossover" pipe lose their functionality when your using a dual independant runner intake(such as the one I use). I've had Supertrapp 2-1's, a thunderheader, and a pair of Bassani 2-1 pipes and have since switched to true dual Bassani Pro street pipes with equal length stepped header pipes. Guess what? I make more top end hp and actually have gain a few foot pounds of torque around 2500-3000 rpm's with these pipes over the 2-1's I used to run. 2-1's dont garentee more power or torque, regardless of WOT or not. There is alot more to matching up pipes to your engine than people realise.......
 
  #16  
Old 08-22-2008, 08:08 AM
Tin Gizel's Avatar
Tin Gizel
Tin Gizel is offline
Road Warrior
Join Date: Jul 2006
Location: Bealeton, VA
Posts: 1,451
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by KumaRide
Are you sick of these?? lol jk

LOL, I still have V&H on my bike too!!! Maybe that's why i'm sick of seeing them???
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Ink83
General Harley Davidson Chat
12
01-10-2014 09:14 PM
timberwolfz28
Dyna Glide Models
8
12-03-2013 06:41 PM
shrini23
Dyna Glide Models
8
03-30-2010 11:56 PM
DHart
Touring Models
10
09-22-2009 01:44 PM
choppers4life1
Touring Models
27
05-16-2008 08:16 AM



Quick Reply: power differences between 2-1 pipes vs. duals



All times are GMT -5. The time now is 09:01 AM.