2 into 1 exhaust?

Discussion in 'Dakar champion (950/990)' started by BigMac, Jul 15, 2005.

  1. KTMax

    KTMax Ninth of the Nazgul

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    I guess ya'all want this pipe don't you?

    [​IMG]

    Nope... not for sale. But in reality it's a go slower goodie. A 2 into 1 pipe might give some more low-end and midrange torque. At best. Typical a 2 into 1 will loose power from midrange to the redline 'cos it doesn't flow as good as two pipes & cans at higher revs. Compared to a stock system with say, open Akra's.

    It 'only' saves weight, makes room for the extra fuel tanks and there are no hot pipes around the engine and shock.

    And it looks damn cool... :evil

    [​IMG]
    #21
  2. BigMac

    BigMac Been here awhile

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    Nope... not for sale. But in reality it's a go slower goodie. A 2 into 1 pipe might give some more low-end and midrange torque. At best. Typical a 2 into 1 will loose power from midrange to the redline 'cos it doesn't flow as good as two pipes & cans at higher revs. Compared to a stock system with say, open Akra's.

    It 'only' saves weight, makes room for the extra fuel tanks and there are no hot pipes around the engine and shock.

    And it looks damn cool... :evil

    [​IMG][/QUOTE]
    That's not necessarily true, it largely depends upon the tuning of the pipes with the camming and ports. Some of the fastest jap 4's, Mat Mladin's Gixxer for example, uses a 4-1 setup. The P-D rally bike shown above dyno's at 8-10 more ponies than the production version of identical displacement. Of course those engines are handbuilt, ports finely machined and matched and I suspect may have higher lift cams with a bit different cam timing. If I can get some basic engine and cam parameters I plan on building a 2-1 and will likely also play with cam timing a bit. My goal, in addition to big weight loss and availability for saddle side fuel tanks, is a broader and smoother torque curve. I also suspect I will find at least 5 more ponies up top. Not that this bike needs 'em, heck I'd be happy with 75-80 hp, I'm just looking for better throttle transition and maybe better fuel economy along the way.

    Looking at the Rally bike shown above, a few features really stand out. Those big side fuel tanks and low routed exhaust could be easily matched to my Ortlieb soft panniers. I'm thinking 400 mile fuel range, smoother power delivery and ability to carry all the camera, climbing and camping gear my heart desires. I'm salivating just thinking of the possibilities. Secondly, have a gander at that rear sprocket. Whoa, that thing is huge. Wonder what kind of gearing they used. 17/48? I'm presently running 16/42 and have been contemplating 16/45 since I primarily ride off-road and have no desire to see triple digit speeds with this bike. As soon as this chain needs replacing, the 45T is going on the back.

    To the previous inquiry concerning changes from Rally bike to production: The biggest change I am aware of, besides the obvious fuel tank and longer travel race valved suspension of course, is the engine oiling system. The Rally bikes used what appeared to be a very large (5-6L?) alloy sump located under seat along with an auxilary pump for higher flow rates and ability to use a 5 row oil cooler mounted just below lower triple clamp. Touratech USA attempted to offer an oil cooler (3 tube) for production models but the system suffered dangerously low oil pressure thus project was scrapped. I don't know that an oil cooler is necessary for most usages on this bike however a small auxilary electric pump would apparently be required if one were to install such an item. Take care.
    #22
  3. scottabshire

    scottabshire IMissMyKTM

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    has anyone thought of refabbing the tanks so they are fatter and hold more?
    #23
  4. Stephen

    Stephen Long timer Supporter

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    Okay, fellas, I like where this is going. I'm not fast anymore (well, probbily never was... ) so the stock bike has more than plenty of power for my needs. And mine exhibits darn good controllability via the throttle... but... it could be better. And that's a lot more important to me than peak HP, or even a lot of HP all over. Driveability, that's what I'm talkin' about.

    My experience with 2-1 vs 2-2 exhausts is limited to the auld /5. In that case, the 2-1 yielded smoother response to the throttle, and what felt like flatter torque and power curves compared to the Dunstall knockoffs that were on it. It may well have been softer on top, but certainly not much. In the case of the 950, with the stock setup, there's power from 4.5 all the way well past 7.5, and still going pretty strong at redline, so with six gears... well, there's plenty to work with there. I'd not shed tears if I lost some oomph up there above 8 somewhere. Even with the 16T CS, I rarely see top gear except on very long open roads. Look, 85mph seems pretty fast to me these days, although I do like to visit the ton once in a while.

    I understand (just book-learnin', mind you) about the equal vs unequal header thing. I didn't mean to imply that they ought to be equal, just that my imaginary tube-bending exercise yielded a rear pipe even more unequal than stock. The pics of the rally rig and the 990 were great! The rally pipe is even more shorter than the one in my gedanken experiment; the SuperDuke pipe shows some real creativity, and would really get in the way for us. For me.

    Bottom line: I'd gladly trade top-end, and even some mid-range, to gain better throttle control and a buncha room in back.
    #24
  5. Stephen

    Stephen Long timer Supporter

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    You good at pressure-injection molding polyamide?
    That's a kind of nylon for us Yanks. So it's not quite just a matter of cut and weld as with steel. Hell, I don't know, maybe it is, but I've not run across fabrication as a common manufacturing method for PA for things like tanks.

    950 tanks are made by Acerbis, right? Or is it Elkamet? -- either certainly know their stuff.
    #25
  6. neduro

    neduro Addict

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    On the extended fuel range thing... I've got an idea in my head to make some rally fairings for the 650R (yes, I know I can buy them if I want to pay more than I did for the bike, but I don't!) and one of the things I stumbled across is this company:

    http://www.fuelsafe.com/

    I haven't called them yet, but my goal would be a couple of long, slim 2.5-3 gallon "gas bags" to integrate into a carbon fiber fairing.

    I raise the point here because the same thinking might be applicable for those looking for extended range- build the fuel bladders into the bottom of your luggage, in effect.

    BTW, my bike has been consistently going 160-180 before the light comes on, and there seems to be 1.5 gallons left when the light goes on and stays on. I filled mine up from dry at a gaspump and put in 5.988 gallons. I'm impressed- I used to get only about 30-33mpg from my 1100GS.
    #26
  7. TymeRider

    TymeRider Been here awhile

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    I just got back from a 3 week trip up to Prudhoe Bay, AK and back. 9300 miles in 20 days. Here's some fuel data from my trip:

    Longest day: ~850 miles
    Best mileage for a tank: 44 mpg (55-65 on nice level graded dirt road)
    Worst mileage for a tank: 28mpg (75-95 on pavement with lots of twisties and hills)
    Average mileage for trip: 37.5 mpg
    Most miles out of a tank: 240 miles
    Earliest reserve light came on: 135 miles
    Latest reserve light came on: 188 miles
    Average at which reserve light came on was about 158 miles if I was getting 37.5mpg on that tank.
    I could regularly count on going 60+ miles after the reserve came on.
    I was carrying extra fuel (Kolpin 1.25gal tank + one 2L Touratech plastic bottle) for the last leg into Prudhoe Bay and for the southeastern leg of the Campbell highway between Ross River and Watson Lake.

    On the 240 mile tank, I did not run her dry and was able to put 6.1 gallons in the tank. I've removed all the smog equipment and my filling technique was as follows: with the bike on the sidestand, fill the right-hand side first, then fill the left-hand side until the gas level is up into the filler tube ready to run out, close the left-side cap, go back and fill the right-hand side until the gas level is up into the filler tube, and then close the cap. Ride and do not park the bike in the heat. :rofl With this approach I several times was able to get 6.1 gallons into the tank without having run it dry.

    Oh, and the 950S held up perfectly with no mechanical issues. This is clearly the best bike I have ever owned or ridden.

    Doug
    #27
  8. Shamal

    Shamal Adventurer

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    I was wondering why I hadn't seen you on 101 recently!
    #28
  9. TymeRider

    TymeRider Been here awhile

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    Hey there. Been meaning to get in touch with you. We should get together for lunch someday. I convinced another guy here at work to buy a 950. He flew back to Chicago, bought a used one and rode it back here about 2 weeks ago. Gonna start our own company KTM club. :rofl But maybe we'll make it the WarmSprings KTM club and let you join.:D
    #29
  10. KTMax

    KTMax Ninth of the Nazgul

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    Only that?... Should be easy... :D

    Be prepared to get offered a very well paid job at Akrapovic or another exhaust manufacturer. :freaky

    It's let's say, 'extremely likely' that it ends up in an either/or situation. IMO you'll be very lucky if a DYI 2-1 gives a wider spread of torque extended to the lower end of the rev range alone. Gaining top end power at the same time would make this system a masterpiece to say the least. The chance of creating some nasty dips and holes in the power & torque curves is much more likely.

    Every exhaust is a compromise between all the variables at play. Power & torque at various points along the power curves, weight, looks, noise, available space etc. etc. (Re)Calculating an exhaust is insanely complicated and even after that it takes a lot of experience to make a good exhaust from the numbers. Just the theory won't cut it. Improving on a well developed exhaust (like the 950 system) without this knowledge and experience is about as likely as spotting a UFO this afternoon.

    But a 2-into-1 will give the space for auxilary fuel tanks, save weight and allow the relocation of the oiltank under the seat. I'm pretty sure this are the very reasons the Factory rally bikes have one too.

    Pls, keep us posted on the developments! :thumb
    #30
  11. gato88

    gato88 Adventurer

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    AFTER SEEING A GHOST,MOTOGP CARMEL VALLEY ROAD,

    i WAS INTERESTED IN PLUMBING OF EXHAUST PER SAY OF A 990 super duke,interesting I'm told that twin akros , after pitching a ,shall we say microwave of exhaust,produced 130hp down and dirty,with mapped fi
    to a gnats eyelash,ahhhhhhhhhh something about a new r1 that thought he was somebody on laureles canyon road

    what more can i say
    nada
    #31
  12. craigincali

    craigincali I'll try it.

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    Tom Crawford from TC Exhaust did a bitchin' RC51 2 into 1. I am sure he can do it for a 950 also. Someone would have to "donate" their bike for the project. He works fast IMO and is a stand up guy, great prices.

    He had a link to his webiste in the vendor forum......
    #32
  13. neduro

    neduro Addict

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    Anyone notice that the new 950 Supermoto uses downpipes?
    #33
  14. KATO

    KATO Supa grannie glide

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    Hey guys, have been running a 2 into one for about a month now. Seat of the pants feelin is that it has certainly has lost a little above 7500 BUT smoother off idle, pulls stronger till 5000 no more roughness between 5000-6000. Constructed the collector out of 50mm 304 stainless steel, internally and externally tig welded. Running a 60mm core stainless muffler, 450 long and have to use a bung as it is way loud without it.
    #34
  15. PeeBee

    PeeBee Giant leap for me!

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    How could you? Post this without pics? So...please?
    #35
  16. K2m

    K2m ....58....

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    Did you make your own headers or modify the stock. If you made your own what ID did you use. Also the approximate length of each header. It sounds like you have been successful at maintaining power, if not increasing its more usable range. This information is important for our database of what works and what does not for the future pipe builders amongst us. Thank you for your contribution and a BIG WELCOME to the list.

    Don't miss our carburetor tuning discussion here:-) http://http://www.advrider.com/forums/showthread.php?t=79837&page=1&pp=15

    There is nothing like sitting on the LC8 when the cam timing, Trumpet length, header length, ignition timing and corrected air fuel ratio come together..... the front pops up without trying.
    #36
  17. KATO

    KATO Supa grannie glide

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    Well i would but dont seem to be able!

    "you may NOT post attachments"
    #37
  18. K2m

    K2m ....58....

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    You need a free photobucket account. You upload your image to photobucket then link it through "Insert image" above. Use "IMG" link :thumb

    http://photobucket.com/
    #38
  19. K2m

    K2m ....58....

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    KATO sent me these photos BigMac.

    This would be a soluton for you. It apears that he uses the original header pipes. Then the new 2 inch collector then one muffler 1.5 foot long with a 2.25 inch core.

    [​IMG][/img]

    A single muffler coming out on the right side.

    [​IMG][/img]

    A single 10lt tank on on the left side yould improve the range nicely.

    Nice idea to keep the original headers...... they work so well :D

    KATO is a fellow Aussi. Last seen heading of to ride his LC8 in the snow. When he returns I will find out who fabricated the collector, and if it is avalable to buy. Many 2 inch slip on mufflers would fit (something on special) even s/s car mufflers of the "resonator > plate > resonator" variety which can generaly be made to speck for $150-180 AUD, and are reasonably quiet, more not-to noisy.
    #39
  20. K2m

    K2m ....58....

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    Or imagine running a single muffler off here:nod You don't have to tell me that I am mad:nod :nod :nod [​IMG][/img]
    #40