Exhaust advantages
Cruiser
Joined: Mar 2013
Posts: 222
Likes: 3
From: Central Wisconsin
Pipes
Well the head pipe dept. has come along way,IMHO 2/1 pipe extracts every bit of what's in the motor,Mr x pipes on the market do agreat job of balance for power and torque.I myself have both 2/1 on a131 ci max perf. 2/1/2 head pipe on my tourin bike plus the balance look if your into that many many factors.
Extreme HDF Member
Joined: Sep 2010
Posts: 14,744
Likes: 402
From: Phoenix '53, '88, '09 Big Twins
...when exhaust headers are connected, as a pulse of exhaust from one cylinder exits the pipe, it leaves a low pressure zone behind it- when the adjoining cylinder is on it's intake stroke, that low pressure zone creates suction which can result in a cylinder fill ( or "charge" of more than 100% as the incoming intake air and fuel is moving at high(er) speed.
this is all affected by the cam overlap ( the period in which the intake and exhaust valves are both open.
if you crawl under any car, you will see that the exhaust headers are all connected, and even the 2 sides of a V8 have a crossover or X pipe.
there is alot of science to ensure that cam choice and pipes work together.
this effect is called scavenging and is free power
the reason that P51 Mustangs and Top Fuel drag cars use individual pipes for each cylinder is that they do not need to make power from 1000 to 5500 RPMs, those motors are designed to run is a narrow high rpm range and prop pitch or clutch slip is used to control the power output....and you've heard those things can barely idle without sounding like they'll poop
Mike
this is all affected by the cam overlap ( the period in which the intake and exhaust valves are both open.
if you crawl under any car, you will see that the exhaust headers are all connected, and even the 2 sides of a V8 have a crossover or X pipe.
there is alot of science to ensure that cam choice and pipes work together.
this effect is called scavenging and is free power
the reason that P51 Mustangs and Top Fuel drag cars use individual pipes for each cylinder is that they do not need to make power from 1000 to 5500 RPMs, those motors are designed to run is a narrow high rpm range and prop pitch or clutch slip is used to control the power output....and you've heard those things can barely idle without sounding like they'll poop
Mike
Last edited by mkguitar; Apr 14, 2013 at 06:06 PM.
Elite HDF Member
Joined: Jun 2007
Posts: 3,873
Likes: 13
From: NW Arkansas
I'm going back to these http://www.mgscustombikes.com/mgs-exhaust/true-duals/. Nothing sounds as good as true dual, and these will perform.
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Elite HDF Member
Joined: Jul 2008
Posts: 4,741
Likes: 45
From: Indian Land, SC
I'm going back to these http://www.mgscustombikes.com/mgs-exhaust/true-duals/. Nothing sounds as good as true dual, and these will perform.
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Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
I have used TDs and now a 2-into-1 on the same bike, both set up on the same dyno. As mentioned above, TDs work better in a particular rev range, whereas a 2-into-1 works over a wider rev range.
In the case of my bike I lost 1HP changing from TDs, gained a few TQ, but the low/mid range is 15% stronger. In addition the engine is much smoother running and also much nicer to ride. I love the improved performance, especially the unexpected improved ride. Current numbers are 101HP and 107TQ.
In the case of my bike I lost 1HP changing from TDs, gained a few TQ, but the low/mid range is 15% stronger. In addition the engine is much smoother running and also much nicer to ride. I love the improved performance, especially the unexpected improved ride. Current numbers are 101HP and 107TQ.