Dong-less DDM exhaust

[flynbulldog]

I'm no expert exhaust tuner but most of what I've read says that mufflers that close to the exhaust port will not work optimally.
To me it looks like another product with no professional R&D nor engineering.
I'd bet it's a loss of HP over stock.



From another forum:

“Backpressure” is a fairly common term regarding the resistance to flow of some piping system (ex: exhaust pipe) when the pressure at some point downstream of this resistance is known. In the case of an exhaust pipe, the outlet of the pipe is open to atmosphere, so we know the pressure at this point is atmospheric pressure. But because there is flow through the pipe, which represents a resistance to flow, the pressure is not atmospheric pressure all the way up the pipe to the engine. If you were to measure the pressure at various points along the exhaust pipe, you’d find that the closer you got to the engine, the higher the pressure would be. This is simply because there’s a resistance to flow of any fluid through a pipe. So the term “backpressure” simply says that there is a pressure drop through a pipe and the pressure at the inlet of the pipe is higher than the outlet and we generally acknowledge that it’s the outlet of the pipe who’s pressure is knowable. This is true for the exhaust on a 2 stroke or a 4 stroke engine. Clear as mud so far?

In the case of the 4 stroke, the desire is to eliminate ALL the burned gasses from the cylinder when the piston gets to TDC - so the more backpressure, the higher the pressure will be inside the cylinder, and the less exhaust gas we will be able to expel. We don’t want those gasses inside the cylinder, so we want the backpressure on a 4 stroke to be as low as possible. Here’s a decent discussion on 4 strokes:
HowStuffWorks "How do exhaust headers work to improve engine performance?"

I do like the look much better than the swollen penis.

[flynbulldog]

Why do you think the engineers at Ducati (termi?) went to all this trouble to make the head pipes so long on the exhaust for the new 1199?

My guess is because it was necessary.

[whoopazz1]

Good point... But on a different not icant see DD making something that would not improve gain in hp. Although they might just wanna get the crowd that's looking for a lean look a opposed to gains.

[Wonway]

Didn't Sputnick's bike lose HP with the current version?

[flynbulldog]

All I can say to the team at DD is maybe they ought to look into this:

http://www.epi-eng.com/piston_engine...technology.htm

Amazon.com: Scientific Design of Exhaust and Intake Systems (Engineering and Performance) (9780837603094): Philip H Smith, John C Morrison: Books

Amazon.com: Scientific Design of Exhaust and Intake Systems (Engineering and Performance) (9780837603094): Philip H Smith, John C Morrison: Books

[Jonny DeWog]

Originally Posted by flynbulldog

......
To me it looks like another product with no professional R&D nor engineering.
I'd bet it's a loss of HP over stock....

Agreed......DD seem to be great advocates of (questionable) "form over function"..

I do like the look much better than the swollen penis.

I would think a dog's turd looks better than that swollen penis thing!

Originally Posted by whoopazz1

Good point... But on a different not icant see DD making something that would not improve gain in hp. Although they might just wanna get the crowd that's looking for a lean look a opposed to gains.

Arrow
Termignoni
Akrapovic
Yoshimura
Leo Vince

..........I don't see double-dong sharing accolades with such company anytime soon.

Jdw

[3-stroke]

Hmmm........is there a history of the 134dd performing poorly that I've not been around long enough to see?

I do remember Sputz' thread about dropping power, but he's got so much crap (I mean that in a good way) on his machine it'd be hard to pin it on the pipe at this point, yes?

I'm going to wait for dyno sheets, both from Double-Dog and some private owners, before I slap the POS label on it.....but don't let the voice of reason hold up the bash-fest!

[Wonway]

Originally Posted by 3-stroke

Hmmm........is there a history of the 134dd performing poorly that I've not been around long enough to see?

not really, just a few posts of people liking the design and then a WHOLE slew of people putting them on with no real facts to back them up besides the drool of the new owners.

I don't recall any 3rd party tests.

Nor on the EVR air box, velocity stacks or other mods that Sputniks did. It would be hard to say for sure where the problem is, but just sayin that don't believe everything thing you read on the Internet.

[Sputniks]

Originally Posted by Wonway

not really, just a few posts of people liking the design and then a WHOLE slew of people putting them on with no real facts to back them up besides the drool of the new owners.

I don't recall any 3rd party tests.

Nor on the EVR air box, velocity stacks or other mods that Sputniks did. It would be hard to say for sure where the problem is, but just sayin that don't believe everything thing you read on the Internet.

They make things look pretty. But not faster.

[Kierownik1]

Dynojet comparisons of 134DD full titanium Exhaust with full Termignoni race system - Ducati 1098:



+ significant weight saving over Termignoni or any other system makes it pretty fast for me