I am about ready to have my 2 into 1 exhaust system put on my 98' M900.
The header on the new system is one size up about 2'' (so I have been told).
My question, should I install torque cones?
I plan to run a Two Brothers M2 exhaust...with a P1 power tip if the system is too loud!!
Thanks for all advice!!
Do you mean a noise type device in the end of the muffler or anti reversion tubes/cones near the front of the headers/exhausts?
Quote from: koko64 on February 12, 2012, 11:26:53 PM
Do you mean a noise type device in the end of the muffler or anti reversion tubes/cones near the front of the headers/exhausts?
the anti-reversion cone right at the heads
Are you trying ones that are removable and not welded in, the type that fit flush with the pipe flange?
Then you can dyno test the pipes with and without them and report back . ;D
Quote from: koko64 on February 13, 2012, 12:46:19 AM
Are you trying ones that are removable and not welded in, the type that fit flush with the pipe glange?
Then you can dyno test the pipes with and without them and report back . ;D
Not really in the financial position to test & retry position.
Was hoping someone with knowledge & experience would be able to give me an opinion.
My mechanic didn't think it was needed.
Wont be able to install system for several more weeks...so any opinions will be considered!! [beer]
Brad Black's bikeboy.org site has some 2-1 data.
I think I remember some 2-1 testing on Doug Lofgren's MPS site.
I've never tried or tested a 2-1 on a Ducati (only Harleys). Anti reversion tubes were used in big bore pipes on drag racing Harleys to mitigate tuning issues.
You could road rest the cones and compare sans cones to see if they help the bottom end and mid range power or smooth out any tuning issues in the lower rev range with those large diameter pipes.
The question for me is whether the cones will help low/midrange power/torque or just fuction like a restrictor and hurt petformance everywhere. I think its at least worth road testing both settings to see if the motor pulls cleaner and stronger at street legal speeds.
What is the diameter of the cones at each end? Does the motor have V or W stamped on the heads? My personal opinion is based on the testing and data of others with the 900 two valve motor. You would be surprised how well the standard headers work.
Interested to see what you find.
"What is the diameter of the cones at each end? Does the motor have V or W stamped on the heads? My personal opinion is based on the testing and data of others with the 900 two valve motor. You would be surprised how well the standard headers work."
Koko64,
I have not bought cones & I don't think I am going to.
My heads are the "W" version, :'(
I installing the 2-1 system purely for the look [thumbsup]
I just thought if it was considered a definite improvement I would use the torque cones
Sometimes you just have to try stuff back to back to really find out unless you see a test conducted by someone you trust.
One test you will be able to do is compare the stock system headers to the 2-1. Maybe you can't afford to dyno test them but you may get a feeling with riding both settings of the pros and cons. Is the guy fitting the pipe going to tune it? Will he test ride it or maybe use a gas tester?
I'm curious as to how a 2-1 will work with the W heads and 900cc. It will be interesting what your test ride impressions are.
Good luck.
Quote from: koko64 on February 13, 2012, 01:35:47 PM
Sometimes you just have to try stuff back to back to really find out unless you see a test conducted by someone you trust.
One test you will be able to do is compare the stock system headers to the 2-1. Maybe you can't afford to dyno test them but you may get a feeling with riding both settings of the pros and cons. Is the guy fitting the pipe going to tune it? Will he test ride it or maybe use a gas tester?
I'm curious as to how a 2-1 will work with the W heads and 900cc. It will be interesting what your test ride impressions are.
Good luck.
Thanks!!
My mechanic is actually the previous owner.
He installed the FCR 41's, Ohlins rear shock etc
He also the one who planted the seed in my head about the 2-1 system!!!
He is going to be doing a full service at the same time.
Belts, valve adj, along with new sprockets & chain.
I am also installing a shaved seat & rear height 30mm spacers
The M900 should feel like totally new bike...to me at least!!
i googled them and lots of people who make pipes say they don't work, while some owner say they've noted a difference with them. all harley based. maybe the rpm range differences may come into play there.
pity it has w heads.
I think unless you have a lot of resources at hand, you'll have to settle for basic rules-of-thumb, and common sence.
When talking about 2-1 exhaust systems, there are a couple of different versions to consider.
In certain engine configurations "2-1 exhausts" can be used to enhance engine performance in some respects, in others you have to take precautions to avoid detrimental effects.
Basically, I believe engines with evenly spaced combustion events tend to belong to the first cathegory. By implication, this would render Ducati engines "type 2" engines; i.e., there's not much scope to use a 2-1 exhaust to enhance engine performance.
Since I like 2-1 systems from aestethically ( I just like the look) and practical (no muffler obscuring access to the drive chain) reasons, I've spent some time thinking about and making 2-1 exhausts.
Basically, what I came up with was that the best compromise if you don't have the opportunity to test things out on a dyno is to use the principle of independent headers and just join them in a common collector / silencer assy.
Since I've been exclusively working on 2V engines, and using whatever formulas generally available as well as empirical testing, I have arrived at systems using headers 700 mm to 800 mm long (from the exhaust valve face), exiting in a collector section of considerably greater section area (150% to 200%) in order to terminate the header section, and to promote a negative pressure wave reflection. Mainly, I beleive by adhering to these principles, you do not optimize anything, but you do avoid major disasters.
The graph below (hope it comes out readable) shows the same M900 MY 2002 with everything stock except Silmotor slip-ons (red) and homemade 2-1 as per above + open airbox lid and dynoe'd PCIII.
This happened before I had learned that owning a Duc means spending money, so I did not dyno the bike with the 2-1 system only. Would have been interesting, and worth the money.
(http://i855.photobucket.com/albums/ab117/Monsterhpd/HPDcomparo.png)
In my opinion, if you're just looking for something that looks the way you want, and are not into heavy performance tuning, use whatever exhaust configuration you think looks right, observing the following rules-of-thumb:
1) Use standard header diameter (or very close, like 38 mm inside diameter);
2) Use header lengths around 700mm to 800 mm;
3) Use as little back pressure as possible in the basic system, since no 4-stroke engine "likes" exhaust back pressure
4) Provide Db killers or whatever you like to get your bike thru whatever noice tests you're likely to encounter.
5) No rule, really.... more back pressure will likely improve lower-RPM torque, and hurt higher-RPM power. Might actually be more rewading to ride ....
Thanks for the contribution and dyno chart. Thats going in the "exhaust folder".
Cheers.
Thanks for your input MonsterHPD!! [beer]
Do you have any pics of your 2-1 system to share?
Aloha
Well, ... this picture is the first "development prototype" and not very pretty, but it's the actual exhaust used for the dyno graph shown:
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Tv-tillett_1.jpg)
For our "rain bike", nominally for wet track days but actually used all the time by ourselves and everyone we know with momentarily non-propulsive vehicles, we fabricated an exhaust with the aim of creating an exhaust that would be impervious to minor wash-outs but still designed along common-sense rules-of-thumb:
(http://i855.photobucket.com/albums/ab117/Monsterhpd/IndraExh1.jpg)
Instead of using the crude collector version shown in the first pic, this time we used a "Y" header connection to the collector, but the same header lengths (780 mm to 800 mm in this case). With no dyno chart to use as a proof, the general verdict from everyone riding this bike is that for a not-tuned (i.e., reliable ...) 900, it runs very well indeed. So far, it also tends to run when other, more "tended-to" bikes do not .... and since the verdict is mostly from people with bikes not running at all, maybe it's not very neutral.
(http://i855.photobucket.com/albums/ab117/Monsterhpd/_DSC3615.jpg)
Anyway, while the engine is stock, suspension is not; at the rear there's an Öhlins, and at the front the Showa has been modified to function properly as described in another thread some time ago. Very soon, I'll post what I believe is the final and most practical way to improve on the front suspension short of buying an Öhlins fork.
The improvement you get from good suspension has to be experienced to be believed. Once experienced, there's no way back ...
Thanks for the pics!
Your system looks very similar to mine other than....mine is in 5 pieces (sprung joints).
Very nice looking race bike [thumbsup]
one thing that you'll notice about torbjorn's system is that the header pipes have an expansion before they hit the collector. this will give a definitive end to the header. not sure if that's important or not, never tried it.
Well, maybe some explanation could be of general interest.
The design was based on two requirements:1) Equal-length headers, and 2) 2-1 system.
Since I had some problems to join the equal-length headers at the right (...?) header length, I reasoned I terminate the effective header length by providing a pronounced diameter increase, and then join the resulting "chimneys" at some convenient spot. Essentially, a pair of dragpipes joined into a common silencer.
The idea was that the big-diameter part of the headers and the collector should just funnel exhaust and noice thru the silencer, having no basic function other than leading the exhaust away and provide silencing.
I don't know if I came up with the idea myself, or if I read about it; I think the 999 exhaust is made basically the same way: Short rear header directly into the silencer, long front header with a pronounced diameter increase along the way, presumably at about the same length as the rear header length.
A few years ago, I had the bike on the dyno to map the Nemesis ECU with some tuning bits. To check different header lengts I made header extensions to a total of 1000 mm for both headers, and made runs cutting pieces away after each run. This was the result:
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Monster%20Forum/HPDHeaderLengthComparo.jpg)
As expected, longer headers gave more torque at lower revs, and less power at higher revs.
What I did not expect was the result compared to the graph with the complete system: less torque at lower rpm, but more power at higher rpm (that graph is the final, mapped graph). So, clearly, there's something to be had by development work here; if one could combine the best parts into an envelope the result would be quite nice.
As for how to join the headers into the collector, this graph could be of interest:
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Monster%20Forum/IndraHPDComparo.jpg)
The M900 curves are from the 900 with no tuning except air box lid and PCIII and the 2-1 shown previously; the other three are from the rain bike with a "normal" Y joining piece and collector but no silencer (it was broken at the time). Pretty similiar in shape and caracter, and probably a bit of performance to be found with a lot of work, but maybe not worth it. It seems that the Y joint and the "chimney joint" work about the same, and the Y joint certainly looks better (I think).
Well...I wish I had the time & resources to play with the system and try to maximize it's potential.
But this a daily - commuter bike for me so its just going to get bolted up and we'll see!!
Well.... so do I ;D nothing much has happened beyond this mainly academic exercise for 3 years.
Learned some, got confused some, but not quite sure what I learned.
Let's see what these megaphones might do to my ST2-based track bike, to to be finished any year soon [roll]
(http://i855.photobucket.com/albums/ab117/Monsterhpd/Monster%20Forum/DSC_0359.jpg)