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Thread: ESE's works engine tuner

  1. #33856
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    19th June 2011 - 00:29
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    new provisional design, all angles 14°
    I know there is still a curve in the horizontal plane in the header , but that is only after +/- 20cm straight. and all MX pipes need to make a turn like that.

    another thing I've been wondering : how to chose your angles and diameters in the cuts. I've drawn an example to show what I mean. above is a straight cone with angle and diameters.
    below is the same cone on the left and right angled at a straight section.
    If I keep the angle and end-diameter of the cone the same (on the left, 7.13 and 40), than the diameter of the next section becomes smaller (only 38.8)
    If - on the right- I connect the "outside-lines" of the cone to the 7° angled line at the 40mm diameter circle which seems the proper way to me, the end-diameter of the cone hardly changes (39.7), but the angle of the cone is different (7.36°)

    How do you guys do it ?
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  2. #33857
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    23rd March 2015 - 21:24
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    Recently stumbled above the same topic JanBros...

    In CAD you can sketch a circle with the desired dia on an angled plane and connect that to another circle on an offseted (length of cone) also angled plane. I double checked with ConeLayout (thats how I previously did developed shapes) and if you add an angle to the diameter in ConeLayout it cuts the cone at an angle leaving you with an elliptical shape instead of a circle.

    IMO the in-/outlet dia should be a circle with the desired dia to give the right hydraulic diameter, elliptical shapes or other projections will result in a different hydraulic diameter. This way you can also connect the cones to each other no matter which angle you asigned per cone or twist relative to each other you want to use.

  3. #33858
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    30th May 2020 - 23:45
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    Dear jan,

    Used your great Excel to calulate an exhaust for a 75 cc classic enduro named hrd with minarelli engine to run it in german championship fantastic job Jan!
    Thanks! !!!!!

    And we have same Problem as you when using Programm cone layout. ..

    Circumfence and diameter changes with angeling the cone ...found no solution too. ..but i think to use a more professional Tool will solf this... ... cone layout is free...not very advanced... craftsmenship is still necessary to make the cones fit

    Greets. ..grüße. ..wolfgang

  4. #33859
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    19th June 2011 - 00:29
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    I also use cone layout.
    previously I did it cone by cone, but then sometimes halfway the pipe I came to the conclusion it wasn't gonna work and needed to cut of several cones again, so this time I wanted to design the whole pipe first and stumbled on this problem.

  5. #33860
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    8th February 2007 - 20:42
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    Sorry , I wouldnt have thrown so much shit if I had realised you were polishing off the inside welds.
    Here is your cone , angle cut in 1/2 , in SolidWorks.
    First is a thin revolve 359.8*, then the cut keeping one 1/2 , then copy the part and keep the other 1/2.
    Then using the cut sketches , assemble the two.
    Then is SKUSA CR125 Pipe assembly using this technique.
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    Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.

  6. #33861
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    8th November 2015 - 17:28
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    Time for a quantum leap in pipe manufacture and design.
    During the all important blowdown phase exhaust leaves as a say 4 to 5mm high and 30 to 40mm wide flat jet.
    All these round pipe design is maybe not optimum.
    If it was of vital importance to me(it is not) to win bucket races, i would weld a straigth exhaust pipe of four strips,edge-welded going from rectangular at cylinder to square profile at exit.If I possesed a good straigth round pipe I would keep the same crosssection area as function of way from port and test both and compare.
    When that gives a 10% improvement to the four strip thing it will be mathematical interesting to plot the four strips cutting form for practical pipes going round corners.

  7. #33862
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    8th February 2007 - 20:42
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    I have dyno tested a header that matched the oval shape at the flange face on the cylinder , by simply crushing a round cone in the press.
    It matched perfectly at the cylinder and transitioned to round over 1/2 its length ( about 90mm ).
    This made between 1 to 1.5 Hp better thruout the used powerband - 10,000 to 15000.
    Then I tested thye oval to round transition within the length of the slip fit spigot only ( 28.5mm )
    This made near 1/2 Hp more everywhere.
    Jan had told me he had tested this idea on a header with the big Aux duct ears shape as used by Aprilia , with sucsess.
    EngMod agrees with the result , and now I need to revisit the idea with my even smaller 75% duct exit geometry ( including ears now ).
    Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.

  8. #33863
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    25th March 2004 - 17:22
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    Sorry? From reading that it isn't clear if the just in the spigot was 2hp better than the original setup or 1hp worse than the 90mm transition in the header.
    Don't you look at my accountant.
    He's the only one I've got.

  9. #33864
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    19th June 2011 - 00:29
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    Quote Originally Posted by Wos View Post
    Dear jan,

    Used your great Excel to calulate an exhaust for a 75 cc classic enduro named hrd with minarelli engine to run it in german championship fantastic job Jan!
    Thanks! !!!!!
    Tnx, but don't forget to thank Frits and Wobbly. The last thing I want to do is take credit for all their hard work .

  10. #33865
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    23rd March 2015 - 21:24
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    So what you do Wob looks the same as Cone Layout, my issue was fitment cone to cone if you want to turn the next cone lets say 45° to the previous one. Always left gaps (especially in the header if you use the 7° angle). Troublesome for my sub par welding skills

    Other issues I found with Cone Layout was that the developed shapes always were longer than the ones out of CAD.

    d1 = 33,4 mm, Angle1 = 10°, d2 = 34,3 mm, Angle2 = -10°, l = 20 mm => Green Cone Layout Flat Pattern Export, Black CAD Development:
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    The bigger circumference will give a bigger diameter (think thats why a lot of people are using correction factors).

  11. #33866
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    19th June 2011 - 00:29
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    was about to say the same as you Koenich.

    cutting an excisting cone is not the problem, it arises when you want to angle 2 different cones. I don't think there is a solution for it. just don't angle 2 different cones ?


    I've exagerated everything in the drawing below : the dash-dotted lines show where it goes wrong : the angles change in this case
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  12. #33867
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    30th May 2020 - 23:45
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    Thanks to all !

    Quote Originally Posted by JanBros View Post
    Tnx, but don't forget to thank Frits and Wobbly. The last thing I want to do is take credit for all their hard work .
    Jan...i am fully aware that frits and Wobbly had taken part...jan thiel indirectly too ...isnt he thanks to all even the other members here!!

    Pleasure for me to listen and learn so much!

    Wolfgang

  13. #33868
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    30th May 2020 - 23:45
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    Hard for me to explain the issue in english...hope dont tell bullshit

    There is a missmatch if you want to fit a flat bottom cone to a cone with angled top...even when both cones have same general angle. ..solution...avoid that...angle top and bottom same way...then the elips should be the same Circumfence ...

  14. #33869
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    23rd March 2015 - 21:24
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    If you asign the same angle to the next cone it will have the same elliptical shape in Cone Layout, a perfect joint will be possible in 2 positions and the actual hydraulic dia will vary with the angle. The more you think about the cone stuff the more complicated it gets

    CAD with circles as in-/outlet should give a more repeatable solution IMO but as always - it's a 2stroke so who knows...

  15. #33870
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    3rd August 2012 - 02:39
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    Quote Originally Posted by koenich View Post
    So what you do Wob looks the same as Cone Layout, my issue was fitment cone to cone if you want to turn the next cone lets say 45° to the previous one. Always left gaps (especially in the header if you use the 7° angle). Troublesome for my sub par welding skills

    Other issues I found with Cone Layout was that the developed shapes always were longer than the ones out of CAD.

    d1 = 33,4 mm, Angle1 = 10°, d2 = 34,3 mm, Angle2 = -10°, l = 20 mm => Green Cone Layout Flat Pattern Export, Black CAD Development:
    Click image for larger version. 

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    The bigger circumference will give a bigger diameter (think thats why a lot of people are using correction factors).
    Difference
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