What are the pros/cons of the 2-1-2 of the current Ducati exhaust systems?
What are the pros/cons of using 2-2 exhaust system?
Something about the 2-1-2 crossover evening out the exhaust pulses and helping scavenge. If you're going for a 2-2 system the lengths of each have to be similar or the bike may not run right. No FHE, just recalling a little what I've read.
everything i have read/been told says that your headers need to be equal lengths to the crossover, then from there it won't matter.
i am in the disegn phase still. My exhaust will be 1-5/8" and 23" long until it hits the crossover, this will be for a 2-2 system..i like the way the S2R stacked pipes look.
For some reason, the Duc motors seem to prefer a crossover.
2-1 systems don't seem to work well either.
Although, given the layout of the OEM Monster header, I can't see how the motor could tell the difference if the 2-1 was sized correctly. :-\
There's folks that have played at that on dynos.
ok so a 2-2 with a crossover guess that's basically a 2-1-2 without the single pipe section.
Moving the crossover should allow you to 'tune' the range of the power.
Found this
NOW - A couple of people ask about the Cross Over on a Motorcycle - They usually only have 2 Cylinders.
It is actually a little more technical but I'll try to keep it simple.
In the case of 4 stroke motorcycle engines, the reason for a cross over is this...
After a cylindar fires and the piston cycles “up†- exhausts gas vents through the Exhaust valves, along with the remainder of the “explosionâ€, exiting the cylinder into the exhaust system.
This explosion creates 2 pulse waves… a Sonic Pulse - and a Thermal Pulse.
When the faster Sonic Pulse leaves the exhaust it has created a vacuum in the pipe behind it, which air pressure will enter the pipe to fill the vacuum. This air will collide with the Thermal Pulse and cause it to reverse. The timing of this event causes exhausted gases to be returned to the cylinder while the exhaust valve is still open therein not allowing all the spent gas to escape and also polluting the environment for your next stroke cycle with fresh air/fuel mix.
This “Event†is call Reversion and seriously degrades performance and lifetime of valves and cylinder heads.
The Cylinders fire opposite of each other â€" or nearly so on a Harley. So when One side is firing, the other side is idle. Having the cross over pipe allows the pulses to dissipate back and forth between the tubes instead of - or before exiting the exhaust and therein greatly diminishing the effects of reversion and so improve performance and engine life.
Yes - you see a lot of bikes with duels and no cross over. These are usually "Tuned Pipes".. meaning their length and size are tuned to work with the S/T Pulse in such a way that reversion can not return to the engine before the exhaust cycle has ended.
Quote from: Raux on September 17, 2009, 09:22:18 PM
ok so a 2-2 with a crossover guess that's basically a 2-1-2 without the single pipe section.
Moving the crossover should allow you to 'tune' the range of the power.
Found this
NOW - A couple of people ask about the Cross Over on a Motorcycle - They usually only have 2 Cylinders.
It is actually a little more technical but I’ll try to keep it simple.
In the case of 4 stroke motorcycle engines, the reason for a cross over is this...
After a cylindar fires and the piston cycles “up” - exhausts gas vents through the Exhaust valves, along with the remainder of the “explosion”, exiting the cylinder into the exhaust system.
This explosion creates 2 pulse waves… a Sonic Pulse - and a Thermal Pulse.
When the faster Sonic Pulse leaves the exhaust it has created a vacuum in the pipe behind it, which air pressure will enter the pipe to fill the vacuum. This air will collide with the Thermal Pulse and cause it to reverse. The timing of this event causes exhausted gases to be returned to the cylinder while the exhaust valve is still open therein not allowing all the spent gas to escape and also polluting the environment for your next stroke cycle with fresh air/fuel mix.
This “Event” is call Reversion and seriously degrades performance and lifetime of valves and cylinder heads.
The Cylinders fire opposite of each other – or nearly so on a Harley. So when One side is firing, the other side is idle. Having the cross over pipe allows the pulses to dissipate back and forth between the tubes instead of - or before exiting the exhaust and therein greatly diminishing the effects of reversion and so improve performance and engine life.
Yes - you see a lot of bikes with duels and no cross over. These are usually "Tuned Pipes".. meaning their length and size are tuned to work with the S/T Pulse in such a way that reversion can not return to the engine before the exhaust cycle has ended.
Just to clarify...
Harleys DO NOT fire nearly opposite. Our L-Twins do.
Take a look at the 696 & 1100 exhaust...if you have an air-cooled.
The pulses may be translated as....if proper length to the crossover, one pulse will actually help the second pulse pull from the exhaust stroke by creating low pressure behind the exhaust pulse in front of the second...and perhaps i am not making it easier to understand.
sorry, just saw that you actually have a 696....measure your pipes from the exhaust valve to the crossover. Your pipe diameter should be 1-5/8"...or close to that. You can have Burns Stainless take you engine specs and tell you how big your pipe needs to be and where the crossover should be....and then buy some stainless from them for their work. You will need to know cam lift and duration, they have a form to fill out.....i am not affiliated with Burns Stainless....eventhough my last name IS Burns....ha!
some ramblings of mine.
if you search the af1 aprilia forum there's a thread somewhere about 'modifying oem header" in the old tuono or rsv section. it appears the 2-1 fitted to the early rsv and tuono limits midrange, but the top end is about the same. that thread is about modifying the oem 2-1 headers will joining tubes to help fill the midrange. the only 2-1-2 early aprilia was the falco, which was the SS equivalent of the range sort of thing. they have a heap of midrange. never dynod one tho.
999 full systems and 1098 with the long single tube seems to cause the midrange hole they have - the zard 1098 system looks like a 916 system. i'm tuning one this week i believe, which will be interesting.
i don't know if the 2v models rev high enough to really have top end issues, altho my 900m with the arrow 2-2 certainly suffered compared to std headers and slip ons over 7,000 rpm. maybe a touch better under that, but it was then a very narrow power band and a lower peak. in general without a cross over i don't think you'll make the top end.
696 will have relatively short cams and large valves for its size so probably needs to be able to flow more air quicker in terms of diameter maybe.
and i always say it's more a packaging concern first, then a tuning concern later. especially with the ports so far apart. a parallel engine is much easier to tune exhaust wise.
tuning lengths gets back to a specific rpm range too. and it's repeating at multiple frequencies too, so it can be good and 4 and 8, crap at 6 sort of thing in the extreme. or lower peak torque, wide power band versus high peak torque, narrow power band. so it's a compromise.
Why does NCR always uses a 2 in 1 on there race bikes if a Ducati doesn't like a 2 in 1
http://kaemna.de/cms_en/katalog.htm?&view=artikel&artikel=2092 (http://kaemna.de/cms_en/katalog.htm?&view=artikel&artikel=2092)
2-2 exhaust, 118hp
Quote from: Raux on September 19, 2009, 01:18:26 AM
http://kaemna.de/cms_en/katalog.htm?&view=artikel&artikel=2092 (http://kaemna.de/cms_en/katalog.htm?&view=artikel&artikel=2092)
2-2 exhaust, 118hp
but isn't that 118hp coming from a totally built motor....not just the exhaust?
I am not crazy about the way it looks, but i do like the idea of not needing a crossover to scavenge more ponies(hp).
both interesting. maybe ncr just like the look of 2-1, or want to package them that way. maybe the shorter length of the kaemna system is what works ok there, but you'd also need to know what other systems they've tried on the 118hp bike and what the differences were in terms of output and curve shape. std length systems may differ. the honda that won sbk in 2002 had a 2-1 for the second half of the season and it didn't seem to have any issues.
the problem is that unless you build a lot of header sets that are the same except for all being different then you'll never know. and no one has done it as people will only buy what they think looks good or what someone who races and wins uses because it must be better or what they can afford. or what they or a mate can make up. there's no money in it and really other than curiosity not a lot of point. and it's one of those things that if you try 10 different things someone will say "what about 11, you didn't try it" which is really annoying when you like playing and get cut short for some reason. lots of my tests i'd do differently or more thoroughly if i could do them again.
the fact the std style stamped x header on all the older non sbk models seems to work so well for what it is, even on st4s models, probably makes it harder to improve too. and it comes back to packaging more than anything - in terms of an oem system with good sound reduction, etc, two muflers and a cross over may be more effective. the kaemna system is probably lighter as it doesn't have excessive pipe to allow for a crossover that you may not need. altho put that short style on a 999 with two oem style mufflers with cats, etc, and you'll have more weight and cost.
(http://www.europeancycleservices.com/HomeContent_files/image001.jpg)
saw this on http://www.europeancycleservices.com/index.asp (http://www.europeancycleservices.com/index.asp)
2-1-2? 2-2? what is that?
EDIT: found it. Zard full 2-2 sport classic system but the photo looks like they added an H pipe between the two? wierd
a friend of mine has that system...sounds righteous! I have no idea about performance though.
and yes that is the way the Zard system comes out of the box.
the vertical pipe comes around and joins into the horizontal pipe as you can see on the rh side. so it's not a full cross over style exhaust. in my testing sample of one it makes a bit less than a monster or ss, but more than the dual pipe sport classic header. is very loud.
fyi -the DP high mount carbon kit on my FI 900 is 2-2.
Quote from: Speeddog on September 17, 2009, 08:52:51 PM
There's folks that have played at that on dynos.
My personal experience with the RoadRacing (2-2) and a Galasetti (2-1) that I bought from Supertdejuc is that the 2-1 had a few more horses, but less torque, on the top end than the RR. As 99% of my riding is between 3500 and 5K where the RR has more horses and torque, I'm running the RR exhaust now.
did you compare them with std headers and slip ons?
Quote from: brad black on September 27, 2009, 01:25:41 AM
did you compare them with std headers and slip ons?
No, Brad, I didn't. The bike had the RR on it when I bought it, and although I got the OEM set-up, I didn't really care because I knew I wasn't going back and didn't want to rejet for them.
I actually started dyno-ing my mods with OEM carbs/RR, then FCRs/Galassetti, then FCRs/Galasetti/Dynacoils, and finally, I still have to get a run with the FCRs/Dynacoils, and RR exhaust, then I'll be done.
i was just curious. only change i've made to a 900 exhaust header wise was a backward step, but it wasn't that well conceived as a mod.
So has there been any further development on this issue? I am debating how to do my exhaust at the moment. 2-2 similar to the Kaemna system, 2-1-2, or 2-1. As far as I can tell, performance between 2-1-2 and the 2-1 should be the same if calculated correctly. So in theory, it is a question vs crossover or no crossover. Someone chime in here. I thought an advantage of the 2-2 systems is the ability to tune each cylinder more accurately.
I am certainly not the authority on exhaust but I understand that for these engines if you combine pipes correctly it doesn't matter if it splits back out to two pipes. From what I have read the pipe that combines the two needs to be of sufficiant size. And I don't know what that formla is.
However, this may produce a different affect then not having any crossover or combining in relation to power.
Personally I like two pipes out but purely for easthetics.
I am looking to build a 2-2 system. Can anyone chime in on how to properly calculate the necessary pipe length? Not sure if I can use the traditional calculations that say the crossover should be 24" from the manifold. In that case, would it be ideal to have the pipe for each cylinder including muffler be 24"? Thanks.
try Google for the exhaust length and pipe diameter calculator?
Burns Stainless exhaust form (http://www.burnsstainless.com/RESF.pdf)
above is a link to a form that you fill out and burns stainless will give you back the info, they would like you to purchase your stainless from them when they do those calculations.
You don't want to put a muffler before the crossover, or move the crossover closer to the exhaust valve then the calculated 'sweet spot' for the crossover. If space/length is a concern, then do not use a crossover. IMO, exhaust (on my bike) is a fine line between function and fashion. In other words, i am not going to sacrifice performance to have a 'cool to me' style exhaust if it isn't helping the engine, so extra design massaging may be needed to get to a compromise.