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Thread: ESE's works engine tuner

  1. #38386
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    8th February 2007 - 20:42
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    Without making a comment on the actual effect of changes , what's going on with the weather correction for this software.
    You have the difference between 19 to 25*C air temp and 0 to 60% humidity.
    0 cant be correct , but is the air being corrected properly ?
    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.

  2. #38387
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    28th October 2018 - 06:30
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    Uh, I think I forgot to input weather data (correction factor) for red curve
    Can't do it now, only when measuring. It is cheap software.

  3. #38388
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    8th February 2007 - 20:42
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    Do you have a choice of Correction.
    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.

  4. #38389
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    21st March 2014 - 22:00
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    Spark plug distance to piston

    @Wob: you mentioned some when that the distance of the spark plug tip to the piston shall be approx. 6 mm as shown in my sketch... is that valid for flat pistons as well for domed once or a setup with a straight angle/ flat dome?
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  5. #38390
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    8th February 2007 - 20:42
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    For a flat top I have been as close as 3.5mm , but only because the chamber was very small for Methanol.
    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. #38391
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    2nd March 2013 - 15:04
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    Quote Originally Posted by wobbly View Post
    For a flat top I have been as close as 3.5mm , but only because the chamber was very small for Methanol.
    I always try to position the plug gap at the point where straight lines from the squish band meet.
    Is that wrong?

  7. #38392
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    8th February 2007 - 20:42
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    That works just fine for a dome , but of course cant be done with a flat top.
    In that case its just a matter of juggling the toroid chamber shape and the spark gap position.
    I dont know how much is too much as Ive never had a chance to test it properly , but I believe you can get the toroid roof too high , ie the plug boss down very low, and that this geometry may
    affect the scavenging loop arriving from near the rear wall and travelling across the chamber.
    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. #38393
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    28th October 2018 - 06:30
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    Quote Originally Posted by wobbly View Post
    Do you have a choice of Correction.
    No, I can't even export it in excel or something else.
    If we use only corrected blue and black curve, there is still missing complete power top on blue curve with new insert.

  9. #38394
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    2nd August 2011 - 11:11
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    Spark plug to piston distance

    Looking for a bit of help, please. Is there a standard or a formula for calculating the needed distance from the piston crown to the spark plug? This is for a square bore/stroke 85cc motor.

  10. #38395
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    28th October 2018 - 06:30
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    Quote Originally Posted by dtenney View Post
    Looking for a bit of help, please. Is there a standard or a formula for calculating the needed distance from the piston crown to the spark plug? This is for a square bore/stroke 85cc motor.
    I doubt you will find a formula for that. I had a gap lower than 1,5mm on 90cc (18hp) "square" aircooled engine. I was experimenting with head inserts and needed to put a 1,5mm shim under sparkplug in one instance to get more clearance. When I forgot to install a shim once, piston tuched the plug and engine didn't start. It was working fine with about 1,5mm gap, the only difference I saw was clear spot at the center of piston dome, but no detonations visible.

  11. #38396
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    5th April 2013 - 13:09
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    Quote Originally Posted by husaberg View Post

    Good catch Husa! No one had any information back then either!

  12. #38397
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    8th February 2007 - 20:42
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    Peljhan , the factors in play to kill top end are MSV , that obviously has changed dramatically with the closing up of the clearance, compression , that should be the same cc
    or finally maybe the head was deforming previously - as you said the new one was alot stronger.
    In any case the instant result of any factor like this is a big drop in EGT - so you need to start logging this , as to get a real correlation between any two setups you should
    be adjusting the jetting to hit a target egt number..
    The fix is a reduction in ignition timing , past the point where the power graphs cross.

    Re the plug position , the pointers for this exist in Jan finding that a flat roof " bathtub " chamber gave better power over a simple part spherical shape, that pulls the plug gap down closer to the piston.
    Then we have the toroidal shape , that pulls the plug down even further , and testing I did showed this was absolutely the best for a flat top piston.
    The only other factor as mentioned before was my feeling that having a very deep toroid roof , with a large plug boss intruding into the combustion space , may ideologically seem good for flame front positioning
    but could in fact start to disrupt the scavenging loop flow.
    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.

  13. #38398
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    21st March 2014 - 22:00
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    Spark plug to piston distance

    Thank's a lot for all the feedback!

  14. #38399
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    30th May 2020 - 23:45
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    Very very interesting Diskussion... answers about head, flat top, domed, distance plug...squish and the special influences😎 wow...😲

    My next question

    the angle of squish band to the head shape ending to ...for example " bathtube"...


    Which is optimum " crossing" angle of both geometric " flow directions"?

    Crossing 90 degree?... thats what i do🤔

    or with flow from head in direction of squish?...angainst it🤔✋

    Thanks for continuing exiting answers✌🥰

    Wolfgang

  15. #38400
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    8th February 2007 - 20:42
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    In my dyno testing of heads for a flat top piston I tried three geometries of chamber outer wall with the toroidal shape.
    Each was optimized for ignition timing and best power egt.
    First was a wall at the bowl edge of 90* that then formed a radius into the toroid roof shape.
    This needed less ignition and a bigger jet , compared to the original flat roof semi tophat shape - background detonation level was considerably less , and power was up the front side nearly 0.5 Hp and around 1.5 Hp in overev.

    Next was a radius all the way to the bowl edge that was 30* from vertical at the intersection.
    This needed the same setup as above but made around 0.3 to 0.5 Hp more everywhere.

    Last was a straight wall @ 60* up from horizontal , then forming the toroid roof radius - so the radiused roof was higher to achieve the same cc
    This needed more ignition , and a smaller jet , but the power was much the same as the tophat example.

    Squish and cc were all identical and had no radius on the squish/bowl edge , just the sharp corner broken with wet and dry.
    I wish i now had the opportunity to try chamber shapes with the latest piston , having a conical squish , transitioning into a flat top with 50% bore area.
    This is the shape I used in the BSL 500 , but only with a bathtub , as that is what Jan had found worked best at the time.
    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.

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