Hey, new GS owner here in the midwest 2005 GSF, Has anybody heard of putting dual pipes on a GS, and do you think it would be an improvement over a single pipe addon performance exhaust

Quote from: ambisinister on April 13, 2006, 03:55:06 PM
Hey, new GS owner here in the midwest 2005 GSF, Has anybody heard of putting dual pipes on a GS, and do you think it would be an improvement over a single pipe addon performance exhaust

No one makes a dualy exhaust. The only one I've seen done is a custom job on a guy's bike in the UK. If you have it custom built, it should offer the relative same performance increases.

could an ex500 exhaust work with some rejetting?

Dual as in a can on both sides?  Or dual outs?  If you use small cans, an exit on either side would be pretty snazzy...but in order to keep weight down you'd have to use dinky cans and they'd look...well...dinky.

A 2-1 will be lighter, though, and get the same hp gain.


...that's a no on the EX exhaust.

  Now wait a minute.  I recollect that someone did post a picture on this forum of an EX500 dual exhaust system fitted to his GS500.  Where there's a will (and a blowtorch) there's a way.  Also, knowledgeable types say that 2-into-2 pipes are the way to more power on 180 deg twins.  The EX500 is up 10 ponies on the GS; they're not getting it from any one place.  Every little bit helps.      

The headers span propperly but the rest doesn't fit...the bend is too low and there's nothing for it to hang on to.

exhausts always work better when exiting throug one pipe, except for very specialised race purposes. 2 into 1 is always better than 2 all the way through. exhausts work better when they are halved, i.e. 4 into 2 into 1, or 8(if we were so lucky as motorcyclists) into 4 into 2 into 1. race bikes sometimes have twin exhausts to try and get added performance from difrent rpm but these are completly custom exhausts that they pay some lukcy guy 1 million a year to develop.

Quote from: Lopeman on April 13, 2006, 05:42:18 PM
exhausts always work better when exiting throug one pipe...

Wrong.  You can yield the same results with a collected system as you can with a uncollected system, but it requires far more tedious tuning and work.  1-exhaust per cylinder will always be the easiest way to allow the engine to breath at it's full potential.

someone on this board did that a while back... it looked really nice, he built it himself though.
I say go for it and let us know the results
-Kevin

sorry mate, on all street motorcycles a single tail pipe works best. trust me, i'm a hydrolic engineering uni student, hydrolic engineers study fluids, air is a fluid, if you would like i can go into detail why it works better, it all has to do with bernouli's laws of fluid mechanics. as i said, on a pure racing bike where exhausts can be set up specifically to suit an engine at a specific rpm range then dual exhausts work better.

It may not work as well, but that dually that they're speaking of sure looked sweet (can anyone digs those pics up?). The Duc Monsters and TLR, etc. must have made use of their twin pipes  couldn't have been purely aesthetic. IMHnon-egineer-dual-exhaust-luvinO

It doesn't matter what kind of engine or whether it's a street bike or race bike...they all work the same.  For a fluid to run quickly and efficiently it must have a smooth, unhindered path...considering you're a hydrolics student you shound understand this.  Collection an exhaust requires merges, welds, bends, and other nonsense...on top of that, for the utmost performance to be obtained, wave tuning must be taken into consideration (otherwise you'll have exhaust pulses fighing one another...ya know, "a hindrence in flow"...).  An uncollected system bypasses the need to concern yourself with 75% of what a collected system does.  It's simple...smooth pipe. Ask whoever tried to teach you Bernoulli's Laws which would be better...straight, unhindered pipe or one with a couple extra bends and merges?  Then ask them to slap you for assuming Bernoulli's Laws can be applied to an engine's exhaust.

...you may be a student, but I've been building these things for a decade.

(for those who don't know, Bernoulli's Laws focus on fluids at constant speed...that's to say that measuring velocities from two locations will yield identicle, constant results.)

Quote from: bbanjo on April 13, 2006, 07:23:13 PM
It may not work as well, but that dually that they're speaking of sure looked sweet (can anyone digs those pics up?). The Duc Monsters and TLR, etc. must have made use of their twin pipes  couldn't have been purely aesthetic. IMHnon-egineer-dual-exhaust-luvinO

The TL actually has an H-pipe.  The exhausts are independant except for a single balance pipe.  A lot of aftermarket systems...including some Yosh and Akro varieties...are uncollected.  I'm sure they're just unfamiliar with Bernoulli's Laws hahaha

Quote from: makenzie71 on April 13, 2006, 07:27:56 PM
It doesn't matter what kind of engine or whether it's a street bike or race bike...they all work the same.  For a fluid to run quickly and efficiently it must have a smooth, unhindered path...considering you're a hydrolics student you shound understand this.  Collection an exhaust requires merges, welds, bends, and other nonsense...on top of that, for the utmost performance to be obtained, wave tuning must be taken into consideration (otherwise you'll have exhaust pulses fighing one another...ya know, "a hindrence in flow"...).  An uncollected system bypasses the need to concern yourself with 75% of what a collected system does.  It's simple...smooth pipe. Ask whoever tried to teach you Bernoulli's Laws which would be better...straight, unhindered pipe or one with a couple extra bends and merges?  Then ask them to slap you for assuming Bernoulli's Laws can be applied to an engine's exhaust.

...you may be a student, but I've been building these things for a decade.

(for those who don't know, Bernoulli's Laws focus on fluids at constant speed...that's to say that measuring velocities from two locations will yield identicle, constant results.)

The TL actually has an H-pipe.  The exhausts are independant except for a single balance pipe.  A lot of aftermarket systems...including some Yosh and Akro varieties...are uncollected.  I'm sure they're just unfamiliar with Bernoulli's Laws hahaha

Haha power owned

Quotesorry mate, on all street motorcycles a single tail pipe works best. trust me, i'm a hydrolic engineering uni student, hydrolic engineers study fluids, air is a fluid,

no Air is a gas, or vapor if you prefer.  i wont Begin to argue Fluid mechanics with you as you are already convinced with what has been etched into you includeing the above line

"i'm a hydrolic engineering uni student, hydrolic engineers study fluids, air is a fluid" 

while Air and gasses can  tend to follow some simular "  Hydraulic's  " Princibles. it is infact NOT a fluid. Fluids dont compress anywhere NEAR that Air/Vapor's do.   as to 1 pipe being better then 2 or more on an exhaust system for tuning, that would depend on many factors with  Pneumatics  (that would be Air mechanics) being just a part of it.
there is also cost,designer styling, frame layout just to name a few.   

by combining many ports into a manifold its easyer to pipe out from the engine(this would also fall under convenient designing).Tuned headers are just a manifold with alittle more homework done to them in design to produce certin desired effects in flow rate/flow timeing. 

show me a funny car with a single pipe, or a high perfomance Small block V8. you cant tell me the old GM,Ford,Dodge Y pipes rule the tracks.

why do alot of the Big twins use 2 out instead of 2-1 ?  2-1 style might apeal to some more then2-2 but the flow wont change once past the collector. this woud only happen if you REDUCE the diameter of the pipe .  2 inch ID collector dumping into a can with a 2 inch outlet would flow no diff then 2" collector into 2  1.75" single pipes and into 2 seprate cans of same diameter.
if the "Spliter" for example was designed as a T then pulse waves Might be effected alittle. if however the split was designed like a "X" pipe or even a "H" pipe it would not effect  the pusles in a negitive manor.

more then one time someone flying the flag of documented high end education has appeared and said "No thats wrong cuz im a engineer" .   

My education consists of, "this worked and this didnt, OH here is why, damn my hands are dirty"   yet i end up right more often. some one smarter then me splain this please!

Jeez, I didn't think a simple question would cause such an argumentative response. Thanks for all theinfo I was planning on fabbing all my own components with the exception of the cans themselves. My only gripe at this stage of the project is that I'll probably have to remove my centerstand

This entry contributed by Dana Romero

Portions of this entry contributed by Leonardo Motta

For horizontal fluid flow, an increase in the velocity of flow will result in a decrease in the static pressure. The equation describing this effect is known as Bernoulli's law. The most practical example of this is in the action of an airfoil. The shape of an airplane wing is such that air flowing over the top of the wing must travel faster than the air flowing under the wing, and so there is less pressure on the top than on the bottom, resulting in lift.

check this out   http://www.gs500e.co.uk/gallery/Members-Bikes-Gallery-1/jim1f

i remember levlers bike being the first one ive seen twin piped
http://www.gs500e.co.uk/gallery/Members-Bikes-Gallery-1/100_1031
http://www.gs500e.co.uk/gallery/Members-Bikes-Gallery-1/100_1037

Quote from: ambisinister on April 13, 2006, 08:03:50 PM
For horizontal fluid flow, an increase in the velocity of flow will result in a decrease in the static pressure. The equation describing this effect is known as Bernoulli's law. The most practical example of this is in the action of an airfoil. The shape of an airplane wing is such that air flowing over the top of the wing must travel faster than the air flowing under the wing, and so there is less pressure on the top than on the bottom, resulting in lift.

That really doesn't apply to an exhaust, though.

Quote from: Blueknyt on April 13, 2006, 08:07:30 PM
i remember levlers bike being the first one ive seen twin piped
http://www.gs500e.co.uk/gallery/Members-Bikes-Gallery-1/100_1031
http://www.gs500e.co.uk/gallery/Members-Bikes-Gallery-1/100_1037

That's just badass!

QuoteThe most practical example of this is in the action of an airfoil. The shape of an airplane wing is such that air flowing over the top of the wing must travel faster than the air flowing under the wing, and so there is less pressure on the top than on the bottom,

very good, now this princible applys to straigt pipes of same size directing same volumes of Air how? or even collected air from 2 smaller diameter pipes into a larger diameter single pipe then redirecting and dividing that volume of air back into 2 pipes of slightly smaller diameter then the collector, but no smaller diameter then the head tubes (never seen it smaller then head pipes anyway)  ?    AS long as the split is the same on both sides and is let out equaly to what comes into the collector there is no change

Having twin pipes going to a single outlet (2 to 1) could yield better performance than twin outlets if its tuned to use the engine pulses to create a scavenging effect.

As one exhaust pulse travels down the pipe it creates a low pressure wave behind it that can help suck the next exhaust pulse out.

This is the theory behind fitting extractors to car exhausts.

Quote
From www.pacemaker.com.au

Scavenging is one of the most critical parts to a design of a header. The tubes volume (diameter and length) is chosen to represent a discharge of spent fuel or pulse being discharged from the engine at a given rev range (usually mid to top end), without competing with the next charge. This pulse then enters the collector cone with a greater volume than the surrounding connected pipe(s). This creates a low pressure (or vacuum) at the exit of the next pipe. This vacuum then in turn sucks at the next pulse travelling through the next pipe in the sequence, vacuuming or scavenging the cylinder bore clean. This aids towards an unpolluted cylinder bore, ready for the next clean dose of air fuel mixture.


But as mentioned, a 2 to 1 system could have more welds which also creates turbulance that limits flow. ie. Bad for performance.

So a "good' 2 to 1 tuned system will outflow a 2 to 2 system. Pipe over cone design is the best way to join pipes to ensure no pipe ends face into the exhaust flow.



Good


Bad

The H pipe on the stock system is also used to create the scavenging effect, allows a pulse reflection which can help extract more exhaust from the cylinder allowing for more efficient operation.

H pipes can also reduce exhaust drone and reverberation.