RS Warrior Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
2,255 Posts
Discussion Starter #1
I have heard talk of this over the years, but would like to know more from you guys.


What are the benefits of equal length exhaust pipes?


What length is documented to give the highest yield of HP/TQ?


Do bendy or straight pipes yield more power?


How long of a straight section of the "tail" pipe is optimum?


Thanks!
 

·
Registered
Joined
·
2,196 Posts
From what I understand...its all about back pressure. That means baffles or bends. What ever combination creates the right amount of back pressure for your system gives the best torque. Now, with that said, I wouldnt think the length of the pipe would matter much once the baffles are in place. In an instance like the pipe on my bike, the headers are equal length. The bends in them that make the pipe fit the bike cause the back pressure. The equal length makes them have a great sound. I have a dynoed 89.5hp and 113.2 ft/lbs tq.
 

·
Registered
Joined
·
8,215 Posts
Header science is a can of worms. (pun intended). Its a trade off, sacrificing torque for horse power or horse power for torque.


First determine what the average operational rpm and the maximum engine rpm is for your intended usage.


The larger pipe diameters will increase horse power & loose torque.


The shorter pipes will increase horse power & loose torque.


The opposite is true for torque.


Smaller pipe diameters improve torque & cost HP.


Longer pipes improve torque & cost HP.


Back pressure improves torque.


The # of bends the head pipes havehas very little if anythingto do with backpressure.


Since this topic is Warrior specific we need to address its engine requirements & limits.


Warrior red line = 5200 rpm. (rpm limiter) On a dyno this is the rpm where the horse power intersects with the torque curve. The torque falls off & the HP increases.


Conclusion: The Warrior is operating in the torque curve throughout its entire rpm cycle, you want to tune your exhaust pipes for torque rather than HP.


IMHO an optimal Warrior exhaust is a 2x1 system using 1 & 3/4 head pipes with a length of 36 to 42 inches. BTW: The elbow off the rear cylinder is restrictive.


What should you use on your bike?


Unless your class racing every week GET THE PIPES YOU LIKE. Weather its for looks or sound or both.


If you notice a reduction in torque AFTER the fuel mixture is correct you can tune the pipes to your liking using torque cones, baffles, tail pipe reducers, loli pops, pyramid stacks etc.
 

·
Premium Member
Joined
·
13,680 Posts
EssKay said:
I got this from the Big City Thunder website...

That is one of the best I have read Esskay, thanks for the link. It is, for the most part, written in English instead of "engineer-speak" The equal length issue is discussed on page 3. Bottom line, yes, the pipes should be the same length. Here is whatthe article says:
"Assuming that an exhaust system is otherwise properly designed, equal length pipes offer some benefits that are not present with unequal length pipes. These benefits are smoother engine operation, tuning simplicity and increased low-to-mid range torque.


If the pipes are not equal length, both inertial scavenging and wave scavenging will vary among engine cylinders, often dramatically. This, in turn, causes different tuning requirements for different cylinders. These variations affect air/fuel mixtures and timing requirements, and can make it very difficult to achieve optimal tuning. Equal length pipes eliminate these exhaust-induced difficulties. "
 

·
Registered
Joined
·
2,196 Posts
Churchkey said:
Back pressure improves torque.


The # of bends the head pipes havehas very little if anythingto do with backpressure.
My pipes are not baffled. Bendy headers. Headers are equal length. 2 into 1 with a megaphone end. I am getting 113.2 ftlbs of torque. 89.5hp. Now some of that was added on with my VBAK! but somehas to com from the bends in the headers.....doesnt it?
 

·
Registered
Joined
·
1 Posts
Header science is a can of worms. (pun intended). Its a trade off, sacrificing torque for horse power or horse power for torque.


First determine what the average operational rpm and the maximum engine rpm is for your intended usage.


The larger pipe diameters will increase horse power & loose torque.


The shorter pipes will increase horse power & loose torque.


The opposite is true for torque.


Smaller pipe diameters improve torque & cost HP.


Longer pipes improve torque & cost HP.


Back pressure improves torque.


The # of bends the head pipes havehas very little if anythingto do with backpressure.


Since this topic is Warrior specific we need to address its engine requirements & limits.


Warrior red line = 5200 rpm. (rpm limiter) On a dyno this is the rpm where the horse power intersects with the torque curve. The torque falls off & the HP increases.


Conclusion: The Warrior is operating in the torque curve throughout its entire rpm cycle, you want to tune your exhaust pipes for torque rather than HP.


IMHO an optimal Warrior exhaust is a 2x1 system using 1 & 3/4 head pipes with a length of 36 to 42 inches. BTW: The elbow off the rear cylinder is restrictive.


What should you use on your bike?


Unless your class racing every week GET THE PIPES YOU LIKE. Weather its for looks or sound or both.


If you notice a reduction in torque AFTER the fuel mixture is correct you can tune the pipes to your liking using torque cones, baffles, tail pipe reducers, loli pops, pyramid stacks etc.
I never thought of the elbow off the rear cylinder being restrictive this helps my decision on designing a custom pipe thanks
 
1 - 9 of 9 Posts
Top