Torque cones on a 2-1 exhaust system....98' M900

[118811]

 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!!

[koko64]

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?

[118811]

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

[koko64]

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 .

[118811]

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 .

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!!

[koko64]

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.

[118811]

"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

I just thought if it was considered a definite improvement I would use the torque cones

[koko64]

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.

[118811]

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!!

[brad black]

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.

[MonsterHPD]

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.



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 ....

             

[koko64]

Thanks for the contribution and dyno chart. Thats going in the "exhaust folder".
Cheers.

[118811]

Thanks for your input MonsterHPD!!

Do you have any pics of your 2-1 system to share?

Aloha

[MonsterHPD]

Well, ... this picture is the first "development prototype" and not very pretty, but it's the actual exhaust used for the dyno graph shown:



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:



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.   



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 ...                  

[118811]

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