Indian Motorcycle Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
5,919 Posts
Discussion Starter #1
Has anyone done any research on TS111 various racing and performance exhaust systems to include "torque cones"?

The claims vs the results would be of interest and a possible way to doing some proper exhaust tuning on systems that have otherwise lost a little torque because of no baffling - inadequate baffling etc..

The science and physics seem to make sense, but real-world dyno numbers would be the ticket.
Venturi effects could increase gas flow velocities, but would you want it at the very end of the line as opposed to somewhere closer to your head pipes? Could this be an easy answer to increasing torque numbers?
Seems to me that some of our vendors would have done this research rather than simply going for the looks, the sound, the manufacturing expediencies.
torque cones.jpg
 

Attachments

·
Super Moderator
Joined
·
4,834 Posts
Interesting subject. When discussing the "loss of torque" due loss of back pressure due to exhaust mods (cat), I always ask if the person doing the mods if they removed the mufflers? We're not speaking of "drag pipe sag" theory since we're not running open pipes. I don't recall any real answers, correct me if I'm wrong, but un-modified mufflers do create back pressure, right?

.
 

·
Registered
Joined
·
5,919 Posts
Discussion Starter #3
Interesting subject. When discussing the "loss of torque" due loss of back pressure due to exhaust mods (cat), I always ask if the person doing the mods if they removed the mufflers? We're not speaking of "drag pipe sag" theory since we're not running open pipes. I don't recall any real answers, correct me if I'm wrong, but un-modified mufflers do create back pressure, right?

.
I agree that the stock mufflers (as well as the cat) do induce an impediment to flows in the exhaust system. This is sometimes referred to as back pressure. Back pressure in a performance sense is NOT a good thing. However, there are other things going on in that exhaust stream to deal with in relation to our V-twins. Reversion of the gas-flow has been thrown out there as well as the Scavenging effects of an X-pipe. These things are well known and well-experimented with in other engines and situations, it seems quite a bit less so with our engines. My interest is in promoting better understanding and maybe better information from vendors.
I am pretty sure that Polaris has to go through multiple design testing procedures for EPA compliance and they do have to test engine performance. Exhaust dynamics and how the entire system performs is a big portion of tuning one of these engines. Once we start changing up the parts and tuning to support our interests in performance/sound/heat we certainly are messing with a complicated batch of variables. Ultimately the exhaust system needs to be re-tuned if we want the best overall out of the engine. I do not have the lab, (outside of experimentation with my own bikes), but am interested in the experimental data and others' experience in this effort.
 

·
Registered
Joined
·
5,919 Posts
Discussion Starter #4
The real simple question is: Has anyone experimented with torque cones on the Thunderstroke bikes?
 

·
Bronze member
Joined
·
2,571 Posts
Best I can tell, those that use the term "back pressure", when talking about exhausts, should replace that term with "velocity" in order to be factually correct.
 

·
Bronze member
Joined
·
3,072 Posts
Tryed them years ago when they first came out,on stroker harleys ,18 inch x2 inch drag pipes.couldnt tell any difference.havent seen those in years.
 
1 - 6 of 6 Posts
Top