Sidecar Flip

Living Legend
Joined
Jul 16, 2006
Messages
6,358
Location
20150 Mc Carty Rd. Deerfield, Michigan 49238
Facts...........

I have to jump in a state that no matter what exhaust system you use on a naturally aspirated engine, the main limiting factor will be the design of the header system. The (Log)(thanks Hombre) exhaust manifold that comes on the R3 as stock is a very inefficient piece of hardware, designed to be aesthetically pleasing and production friendly but not at all efficient in scavenging exhaust gasses from the cylinders during the exhaust stroke (when the exhaust valve is open and the piston is rising to TDC).

To achieve true power gains with a naturally aspirated engine, one must design an equal length header (extraction) system that actually pulls the exhaust gasses from the cylinder(s) as the piston is achieving TDC on the exhaust stroke. If you can visualize it, visualize a "ball" if you will, of spent exhaust gas entering the exhaust system. That ball of hot gas must then create a vacuum behind itself pulling the rest of the spent gas from the cylinder in precise time to the piston travel and valve opening. That's why true equal length headers look like a snake. Each cylinder needs the same length of runner to achieve that scavenge effect.

Designing a true equal length header system involves much trial and error as well as a good understanding of applied geometry and gas flow theory and many hours on a dynomometer to achieve just the right diameter as well as length and finally termination but still making the system usable and aesthetically pleasing. Automotive headers that reside under a hood don't have to be pleasing to the eye but a bike system does.

The end result is a system that achieves proper scavenging, is priced reasonably and is aesthetically pleasing. There is a tremendous amount of R&D that goes into the execution to produce the end result that the consumer (you) want.

Finally, no exhaust system, be it TORS, or whatever, that slip on even with the CAT bypass, that use the stock log manifold are going to give the gains everyone desires. The stock log manifold will never flow anywhere near properly and will never scavenge properly. It's an impossibility.

That's why I've never changed the intake side, leaving the stock air filter in place and the cat box. I feel personally that without adding an equal length header system, I'm basically flushing money down the crapper. You may indeed achieve small gains, but the big change needs to be on the exhaust side of the engine before modifying the intake side. Basically, you can shove more in but if you can't get rid of it, why bother.
 
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Sidecar Flip

Living Legend
Joined
Jul 16, 2006
Messages
6,358
Location
20150 Mc Carty Rd. Deerfield, Michigan 49238
More facts..........

Now, if you supercharge the engine, the exhaust header becomes less relevant. That's because your intake charge is pressurized. That pressurized charge increases the static pressure within the cylinder (basically by providing a denser charge, more fuel/air mixture) and thus more power when the cylinder combusts the charge. At that point, the exhaust header only provides a path for the spent gas to reach the turbocharger or in the case of a supercharger (roots type PTO driven positive charge device), you can utilize the stock log manifold and free flowing mufflers.

In the case of a Roots type device, equal length headers and a free flowing muffler will extract even more power but not especially so with a turbocharger as the turbo needs the shortest possible path from the exhaust port to the hot side of the turbo to achieve the most RPM on the turbine blades. It's imperative that the exhaust maintains the highest temperature possible as it passes over the turbine blades. As the exhaust cools, it looses energy and you want as much of that energy (in the form of heat) to spin the turbine that drives the compressor section of the unit achieving maximum boost without excessive RPM on the engine's part.

That's what is referred to as 'Turbo Lag'. That's when the exhaust gas flow isn't sufficient to spin the turbine at a high enough rpm to overcome the intake charge and achieve a positive pressure. Because of the inherent structural design of a production engine, the boost must be controlled within pre-determined limits to avoid mechanical destruction of the engine internally. That's why turbocharged engines that are normally naturally aspirated have waste gates or blow-off-valves. That valve opens when the turbo achieves a pre determined pressure and vents the excess pressure to the atmosphere. If the engine is structurally designed to take the internal stress of a compressed charge, the blow-off-valve is not needed. Most engines, with the exception of large diesels aren't.

Roots type superchargers don't suffer from Turbo Lag as they are positively driven (via PTO), but are a much more complicated install because of their very nature.
 
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goodfellow

Turbocharged
Joined
Jun 12, 2007
Messages
745
equal legnth vs flow path

i disagree,
to qualify equal length headers as the only means to power increases is misleading to say the least. a good look at the overall picture is needed to see what i am saying. all you have to do is ride a bike fitted with predators and triple k&n's under the bear claw/tune boy tune . there is not one iota of similarity in one to the other. you can say what
you may,but i find the difference very evident. i weigh 279 lbs. i can pull the front wheel off the ground by simply rolling the throttle on. i don't mean to infer any argument here. there is none. a predator system will leave you in a much more satisfied state of mind than any thing that is of stock configuration. i had raask, d&d,jardine, and tors. i cannot,repeat; cannot say in good faith that equal length headers will outperform the predators in their current configuration. the reason being is that predators have been designed for equal flow.this is done by bending and tuning each pipe for overall flow symmetry. dont take my word for this,just look for yourself on the putfile site. you will note the the color of entropy is equidistant .this can only be accomplished through tuning each cylinder to run at the same temperature throughout the power range. this can't be done without good flow symmetry,albeit equal length or otherwise. with proactive engineering thermodynamics,you can have good usable power without the convoluted complexity of equal length spaghetti pipes. aesthetic appeal and tire ripping power is always a good thing. they're called predators,get em whilst you can boys.......:D


greg
 

Sidecar Flip

Living Legend
Joined
Jul 16, 2006
Messages
6,358
Location
20150 Mc Carty Rd. Deerfield, Michigan 49238
i disagree,
to qualify equal length headers as the only means to power increases is misleading to say the least.

--I never said that. What I said was simply was no matter what exhaust system you use on a 'naturally aspirated engine", the main limiting factor (in performance gains) will be the design of the header system. That's it. I also went on to say that the Log manifold that Triumph employs due to cost and production restraints is a very inefficient means of extracting spent exhaust products. No where did I imply that equal length headers are the only means of extracting more power. When you increase the incoming fuel/air charge, you must increase the efficiency of the exhaust extraction method. That's simple physics.

a good look at the overall picture is needed to see what i am saying. all you have to do is ride a bike fitted with predators and triple k&n's under the bear claw/tune boy tune . there is not one iota of similarity in one to the other. you can say what
you may,but i find the difference very evident. i weigh 279 lbs. i can pull the front wheel off the ground by simply rolling the throttle on.

--I suspect at 279 pounds, the revelant position as to where you physically sit on the seat may have something to do with how well the front wheel lofts also.

i don't mean to infer any argument here. there is none. a predator system will leave you in a much more satisfied state of mind than any thing that is of stock configuration. i had raask, d&d,jardine, and tors. i cannot,repeat; cannot say in good faith that equal length headers will outperform the predators in their current configuration. the reason being is that predators have been designed for equal flow.this is done by bending and tuning each pipe for overall flow symmetry.

You must be arguing with yourself. The Predators are designed for equal flow.....just what I said in the beginning.....?

dont take my word for this,just look for yourself on the putfile site. you will note the the color of entropy is equidistant .this can only be accomplished through tuning each cylinder to run at the same temperature throughout the power range. this can't be done without good flow symmetry,albeit equal length or otherwise. with proactive engineering thermodynamics,you can have good usable power without the convoluted complexity of equal length spaghetti pipes. aesthetic appeal and tire ripping power is always a good thing. they're called predators,get em whilst you can boys.......:D

Geeze....more of the same. If you want to give Sam kudo's. That's fine. Sam and I have had conversations about his exhaust system and my hat is off to him for the R&D and the execution. What exactly is your point?
 

goodfellow

Turbocharged
Joined
Jun 12, 2007
Messages
745
the point is

the point is i don't give kudos's to any one. just respect for hard work. that is what shows results.:D. predators show results.period. i never said otherwise,that is my point.everything i say is of pure opinion.every thing you say is of pure opinion. it is my opinion that equal length headers are not needed to gain the horse power that is made by the predator system.it is my opinion that equal length headers would be hard pressed to surpass predators. that is my point. i certainly respect people that think in conventional wisdom that is based on sound logic. i, however,don't think along just those lines.my right wrist and seat of pants have their sense of logic also. sorry if i offended you.do you now get my point?

greg
 

Sidecar Flip

Living Legend
Joined
Jul 16, 2006
Messages
6,358
Location
20150 Mc Carty Rd. Deerfield, Michigan 49238
No Greg, I don't understand.

........................no.

As I retitled my previous posts. Let me state that in no way would I even demean Sam in any way. All I did was state facts pertaining to performance gains versus stock exhaust systems and their inherent disadvantages as well as a little dissertation on supercharging. Those posts are not my opinion, they are sound engineering principles. In retrospect, I should have never titled them as my opinion.

I know very well what it takes to bring a product, any product to fruition, especially custom designed products for motorcycles that you, as the buying public will accept as a quality product at a reasonable price.

Unbeknown to you, Sam and I have had numerous conversations about what he is doing and what I'm doing and our desired end result. I certainly have no problem with you singing praises for Sam, Sam has worked hard and experienced a lot of trial and error just like I have, in bringing products to the marketplace for you, the buying public to enjoy and enjoy at a reasonable cost. So, no, I don't understand your diatribe and you certainly didn't offend me simply because I don't understand the point you are trying to convey.
 
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Molinoman

Living Legend
Joined
Nov 30, 2006
Messages
2,788
Location
Molino, FL
Ride
2017 Polaris Slingshot
Hmmm? Equidistant, I'm going to have to look that one up to increase my word power.
Dennis
 

Tbucket

.060 Over
Thread starter
Joined
Dec 2, 2007
Messages
116
Location
Shreveport, La.
Nervous Newbie

Wow never expected this kind of feedback, controversy , and fantastic relevant information. I am shaking in the corner almost scared to jump in here. LOL But seriously guys , I do appreciate the input . You guys have provided me with the information I was looking for. I am sold, I would like to hook up with Travelguy to get a set coming, but I have been having some trouble contacting him. I hope to hear from him soon . Thanks guys!
 
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