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Thread: ESE's works engine tuner

  1. #33526
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    28th August 2015 - 00:01
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    We can only effectively supercharge a cylinder via the last opening that closes before compression begins. In a four-stroke that is the inlet port, in a conventional two-stroke it is the exhaust port.
    However, you can seriously supercharge a conventional two stroke if you raise the exhaust back pressure along with the intake pressure. Turbochargers do this, but Ricardo tested his sleeve valve two strokes by simply restricting the exhaust. During one test he got a BMEP of 321 psi (22 bar) with 36 psi (2 1/2 bar) intake pressure and 12 (.8 bar) psi exhaust pressure. You could run a really effective catalytic muffler with that back pressure. The mechanical supercharger would take some power to run, so a turbo is probably a better and proven solution.

    You knew all that, though.

    Lohring Miller

  2. #33527
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    Quote Originally Posted by Frits Overmars View Post

    We can only effectively supercharge a cylinder via the last opening that closes before compression begins. In a four-stroke that is the inlet port, in a conventional two-stroke it is the exhaust port.


    Dear Lord, I hope that you are well, like everyone else.
    Excuse me, but I can't help it, such is my admiration for what you say, that I can't hold back from letting you know.
    His words to me are sacred and in them I always see the truth and maximum efficiency in engineering

  3. #33528
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    10th February 2005 - 20:25
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    Quote Originally Posted by ceci View Post
    "His words to me are sacred and in them I always see the truth and maximum efficiency in engineering"
    CECI Sorry, but not sure who you are discussing here - is it Lohring or Frits?

    Then of course I may not be quite 'up there' in my ability to understand things !
    Strokers Galore!

  4. #33529
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    12th March 2010 - 16:56
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    He who hoards the most stuff wins.
    Certainly makes you think how to use the stuff you have, because you can't just go out and buy what you want. Lucky I have an extensive scrap heap and a spare one just down the road to wade through ( within my bubble ).

  5. #33530
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    Quote Originally Posted by WilDun View Post
    CECI Sorry, but not sure who you are discussing here - is it Lohring or Frits?

    Then of course I may not be quite 'up there' in my ability to understand things !


    With all my respects to everyone.
    There are people here who do many great things and prove to be very talented.
    But Mr. Frits, from my little knowledge, is the person with the most experience and wisdom.
    I don't know where I'm wrong, but I enjoy reading everything he writes

  6. #33531
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    13th June 2010 - 17:47
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    Quote Originally Posted by Flettner View Post
    He who hoards the most stuff wins.
    Certainly makes you think how to use the stuff you have, because you can't just go out and buy what you want. Lucky I have an extensive scrap heap and a spare one just down the road to wade through ( within my bubble ).
    Very true. I'm a little envious of your scrap heap. Mine is smaller. By the end of the lockdown we'll all be MacGyvers - able to make something out of whatever's lying around.

  7. #33532
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    22nd November 2013 - 16:32
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    Neels, yeah aware of the Suzuki and others, particularly the vertical shaft marine 2 strokes. I think it was Mercury who connected the lowest main bearing drain to the top of the uppermost main, allowing the oil to seep thru the intermediate labyrinth inter chamber seals.

    Dave, just a product of being old, really old, and waking up in the middle of the nights and the brain going crazy. Probably C19 socially deprived, dementia or some other serious mental disorder. You'll get your turn in 100 years or so.
    "Success is the ability to go from one failure to another with no loss of enthusiasm.”

  8. #33533
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    Jesus Ken , did you use a wood lathe to machine that piston crown.
    I have been practicing making semi flat top TM pistons , so I know it aint easy.
    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.

  9. #33534
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    22nd November 2013 - 16:32
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    Quote Originally Posted by wobbly View Post
    Jesus Ken , did you use a wood lathe to machine that piston crown.
    I have been practicing making semi flat top TM pistons , so I know it aint easy.
    Ha, ha....nope, it was just a rough as guts set-up piston to understand timings. Should be able to do a little better next time, there's a cool place pretty close that should be able to help.

    PS, thanks for the tip though..

    Wood file....turns out there's two types of people in the world....woodies and metalies….I'm a metalie.
    "Success is the ability to go from one failure to another with no loss of enthusiasm.”

  10. #33535
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    28th August 2015 - 00:01
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    Snowmobiles have run turbochargers for a long time. Now there is a factory version. I think this is the future of small two strokes.
    https://www.youtube.com/watch?v=UxZY...ature=youtu.be

    Lohring Miller

  11. #33536
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    10th February 2005 - 20:25
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    Quote Originally Posted by lohring View Post
    Snowmobiles have run turbochargers for a long time. Now there is a factory version. I think this is the future of small two strokes.
    https://www.youtube.com/watch?v=UxZY...ature=youtu.be

    Lohring Miller
    Lohring, - Yes, I agree that at least, its a big step towards the future of small two strokes - I think they are now definite leaders in two stroke development, using turbos with electronics controlling things! Guess the prices of electronics does tend to decrease dramatically later on.
    How are they doing with fuel injection etc? - are they using direct cylinder injection? and I assume that exhaust piping has changed dramatically - I need to check it all out .... somewhere?? - anyway I'll have a browse on the subject.
    Strokers Galore!

  12. #33537
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    12th March 2010 - 16:56
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    Not so fast, dont need no turbos or direct injection, Uniflow, throw the exhaust down the other end of the cylinder.

    Pictured here, piece of Champion grader tool bar, cast iron tool holder out of a old turret lathe and a welded up bearing housing I built years ago for some other un related project, waste not want not.

    And thankyou Frits, your advice is as always very welcome, Im copying the above photo.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  13. #33538
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    21st June 2012 - 14:20
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    Sorry Will,Looks like Rotax is still using a stupid expansion chamber with their Turbo engine!!WTF??

  14. #33539
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    10th February 2005 - 20:25
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    FW190,
    Didn't even know that Rotax had a turbo (you're talking snowmobile engines?) - if so, I haven't studied them as yet - but will have a look soon no doubt! - why the hell would you need an expansion chamber AND a turbo?

    Flettner,
    Yes I reckon! - but the exhaust would still need to close a little earlier (preferably as the fresh charge just gets to it) either by asymmetric port timing or a shutoff valve of some sort! ( a rotating sleeve? ) - just a suggestion inspired by a hunch based on a dream I had a while ago
    Strokers Galore!

  15. #33540
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    4th December 2011 - 22:52
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    Quote Originally Posted by WilDun View Post
    - why the hell would you need an expansion chamber AND a turbo?
    The best way to look at a turbo is to consider it a device that increases atmospheric pressure. Then all the requirements at 1 atmosphere are still there at higher atmospheres.

    It stays a 2T so you still need blowdown, and a plugging pulse. Because of the extra power you can go for a milder tune if power spread is required but the snowmobile drag sleds use very high levels of tune.

    If you do not want to use a tuned pipe you have to go for a Uniflow engine.

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