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Thread: ESE's works engine tuner

  1. #36166
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    8th February 2007 - 20:42
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    Simple answer is 15* at peak power , if the com and squish are done correctly for the fuel,.
    You can flat line the bottom end @ 28* to where the PV starts to open or where the engine obviously starts to come onto the pipe.
    Advance past peak power depends on how much overev to max useable rpm there is , usually anothe 5* , then flat line at 10*.
    If you have too much overev retard , the egt will keep climbing in top gear against the aero load .
    Then you have to use extra fuel to cool the top end egt , not make Hp
    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. #36167
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    15th May 2017 - 14:26
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    Quote Originally Posted by wobbly View Post
    Simple answer is 15* at peak power , if the com and squish are done correctly for the fuel,.
    You can flat line the bottom end @ 28* to where the PV starts to open or where the engine obviously starts to come onto the pipe.
    Advance past peak power depends on how much overev to max useable rpm there is , usually anothe 5* , then flat line at 10*.
    If you have too much overev retard , the egt will keep climbing in top gear against the aero load .
    Then you have to use extra fuel to cool the top end egt , not make Hp
    Currently running 15.1:1 compression with a reasonable squish. Have another insert which would increase it a little more. So I should be bringing the final timing back and building in the over rev. My EGT is still too low I think. Its in the mid 400. Have a new sensor coming with an open tip. 150mm from the piston face. Is that close enough?


    Sent from my iPhone using Tapatalk

  3. #36168
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    8th February 2007 - 20:42
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    What is the fuel and what power is it making ( what engine bore/stroke , whats peak power rpm to see what the bmep is ).
    As with a low bmep ( low dynamic com ) you can run more static com.
    What do you mean " reasonable " squish. You should be running the minimum allowable squish height short of clipping the head with an overev , and shoot for 38M/s squish
    velocity in most cases - generally around 50% area , and in a 50cc probably 0.55 squish.
    MSV is just a guide as if its done right , there is virtually no squish clearance above peak power.
    EGT tip should be on the header centerline about 3X Bore from the piston.
    400* isnt even warm , all race engines run between 600 - 700 *C depending upon the fuel and application.
    Here is an example with peak power at 13,000 , overev to 15000.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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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.

  4. #36169
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    20th April 2011 - 08:45
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    Quote Originally Posted by jfn2 View Post
    Hello Frits... In your concept drawing your example shows a leading directional angle of 30* for the "A" port and it shows it intersecting the bore center line +/- 3/4 of the way down the bore center line from the exhaust port side of the cylinder....
    Is the angle more important or is the placement of the intersection point with the bore center line more important?
    Also could you explain a little more about the 'sum' of the axial scavenging direction degrees and how that is measured?
    The placement of the intersection point with the bore center line was not mentioned at all in my scavenging concept. I hope this answers your first question.
    Your second question is one of those seemingly simple questions for which there is no simple answer.
    In my "Leaning tower of Pisa" treatise I did my best to describe the fluid dynamics of scavenging without formulas. The formula for the axial scavenging angles was unavoidable, but it caused an avalanche of 'what is an arctangent?'-questions. But I do not intend to start a trigonometry course here...

    Calculating the axial component of the combined scavenging flows is not simple, and neither is measuring it. It can be done if you are a millionaire (which I am not).
    Google 'COMSOL Multiphysics' and you will see what I'm on about.

  5. #36170
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    8th November 2015 - 17:28
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    Deleted as nonsense

  6. #36171
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    8th February 2007 - 20:42
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    The crossing point of the A port front wall with the centerline is dependant upon the bmep , and that is largely set by the pipe efficiency.
    A fatter pipe with steep diffusser angles needs the crossing point close to 1/3 from the boost port to the bore center.
    Lesser pipes ( thus lesser bmep ) are around 1/2 way from the boost to bore center.
    Thats just my observation no science involved at all.
    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.

  7. #36172
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    18th March 2012 - 08:35
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    Quote Originally Posted by wobbly View Post
    400* isnt even warm , all race engines run between 600 - 700 *C depending upon the fuel and application.
    This is quite interesting.
    As i have noticed alcohol fuel as methanol makes the best power at ~450 degrees with probes as you mention(and e85 has similar levels).
    But!
    I have also noticed that Pipetemp is affecting powerband the most, power secondary.
    I can get almost the same power at different rpms depending on temp.

    This is very useful in dragracing, at the launch the torque is at a lower rpm level and running down the strip the temp gets higher and moves the powerband upwards, allowing for more topspeed.

    And as a little bonus for those who are interested, ive made a dynorecord again with my tzr250 engine running on E85
    90.7hp at ~11000rpm(quite low rpm, and what made me post this entire post), exhausttemp starting at 430 degrees and climbing to 460 degrees at the end of the pull.(pipes are tuned to get peak power at ~11800rpm at ~600 degrees, my pulls in my dyno is quite short so the temp doesnt rise as it should)

    How did i get this huge gain?
    Well, ive been careful with ignition as this engine seems to like very high values (22 degrees at peak power, had 20 before)
    And as i am planning for new pistons and new plated bores i said to my self, to heck with caution, lets send it =)
    I raised the curve even more at the left side of the peak, but cant remember how much.

    It instantly gave me ~7hp.
    Im sorry to say i dont have any movie of the pulls, but i got a screenshot of the curve(compared to old record)
    Almost no weathercorrection also, it means that the engine actually really produces that number.

    Click image for larger version. 

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