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Thread: ESE's works engine tuner

  1. #37126
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    Quote Originally Posted by Hoebra View Post
    Next week I`m going to make some tests with Nitromethan as fuel. Its 50% Nitro Concentration.
    If I was thinking about running 50% Nitro-methane and a Carburetor on a two stroke. I would keep the carburetor as original, correctly jetted for petrol (or whatever fuel you have been using) and drop raw Nitro (100%) in through a solenoid power jet. Or better yet pump it into the inlet with a small peristaltic pump. We tried this on the dyno. Pumped raw nitro into the carb bell-mouth. Some changes to the ignition at peak torque required but it worked great. It means two tanks, one for petrol the other for nitro.

    This works because Nitro carries slightly more fuel than oxygen. Nitro by itself as a fuel, very rich mixtures are required for the small amount of surplus fuel in the Nitro to be at the correct air/fuel ratio with the inducted air other wise it runs lean. And you don't want to know Nitro when its lean.

    But if you already have a correct air/fuel ratio running the original carb on petrol (or whatever) then all the extra Nitro does, is add oxygen and its own fuel at the perfectly correct air/fuel ratio for itself with a little bit of its own fuel left over to add some enriching of the original base petrol air/fuel ratio.

  2. #37127
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    My suggestion is that Nitro is way, way more effective if used as am additive to a fuel system and engine tune that has been optimized for Methanol already.
    This primarily involves a big jump in compression and a pipe tuned to the much lower Exhaust gas temp/wave speed that will be created by a rich (+ 20 % over stochiometric ) fuel curve.
    The two are very much synergistic in action , whereas petrol/ Nitro is just a simplistic approach with nowhere near the possible capabilities.
    Its like sticking nitros in a stock Avenger Vs a stock Aventador.
    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.

  3. #37128
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    Quote Originally Posted by wobbly View Post
    Anyone got an RZ350 cylinder lying about I could use to do some measuring for a project.
    Got a 1UA, not the 31K, been heavily modified, though some still there. Should find relevant measures here; https://www.rd350lc.net/

  4. #37129
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    Quote Originally Posted by Hoebra View Post
    Ignition needs to be retarded, cause Nitromethan burns faster.
    I would say it´s the other way around, it burns REALLY slow, you need to advance a LOT.
    Nitro topfuel dragsters are having ignition point about 58-65degree before top dead center.
    And those are supercharged, hence a more compressed media, and a more compressed media burns faster than a less compressed media.
    Thus you need to advance ignition even more then they do.

    But!
    Consider they run ~97% nitro, so you might get away with ~25-35 degree before tdc.

    You might also want to try a surface discharge sparkplug(no groundstrap)

  5. #37130
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    20th January 2010 - 14:41
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    bell

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    http://3cyl.com/mraxl/manuals/bell/p...raham-bell.pdf
    i remembered after reading that that the top fuel dragsters used propylene oxide also to speed up combustion.
    its apparently banned now, Cancer causing i think.

    All this talk of methanol does raise a thought can you make the stinger bleed venturi considerably smaller when running methanol or ethanol?

    something old something well new to me....
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    https://www.thumpertalk.com/forums/t...-cylinderhead/
    Am i wrong or is this braided oil line?

    that said
    https://www.flexiducting.co.nz/produ...-exhaust-pipe/
    20mm up
    Quote Originally Posted by Katman View Post
    I reminder distinctly .




    Kinky is using a feather. Perverted is using the whole chicken

  6. #37131
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    Quote Originally Posted by husaberg View Post
    All this talk of methanol does raise a thought can you make the stinger bleed venturi considerably smaller when running methanol or ethanol?
    No. The restrictor diameter depends on the power produced by the engine, not on the type of fuel. But why do you ask Husa? I am curious about your line of thought.

  7. #37132
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    Quote Originally Posted by Frits Overmars View Post
    No. The restrictor diameter depends on the power produced by the engine, not on the type of fuel. But why do you ask Husa? I am curious about your line of thought.
    In the old days we were lead to believe the smaller the bleed the more hp, with a caveat of but go too small and you create too much heat.
    its likely a fallacy. I have always just run the recommended sizes. But never melted anything either
    Quote Originally Posted by Katman View Post
    I reminder distinctly .




    Kinky is using a feather. Perverted is using the whole chicken

  8. #37133
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    I believe the most highly developed nitro burning 2 strokes are model race engines. Today their popularity has declined against competition from industrial gasoline and electric power. To help preserve this history, I wrote a 6 part series. Readers will discover that I shamelessly stole material from members on this site as well as my friend, the late Jim Allen.

    Lohring Miller

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  9. #37134
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  10. #37135
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    Quote Originally Posted by Condyn View Post
    Attachment 351321

    Prepared and ready to test a batch of pipes I built at an eddy current engine dyno. All four sets of pipes have the same tuned length from piston to end of convergent cone and share the same dwell and convergent cones, thus all four also carry 66 % end of diffuser and 77 % end of dwell. Two sets have 33.5 % headers and two sets have 31.5 % headers. Two sets have two stage diffusers and two sets have three stage diffusers. I have added provisions for tophat nozzles to Optimize the bleed orfice. In hind sight there are things I would have done differently for this test, but I believe I will take home a lot of usable data.
    Now I just hope the 75 % exhaust chordal width keeps the ring in. I have had great results with such wide ports in the past, however this was the last time I will ever send a cylinder to millennium. Royal disaster of a chamfer job, completely changing the geometry, even after I left them several notes with my instructions.
    Well the eddy current engine dyno day went very well in my opinion. An honest 10% increase in power from last year. The engine is maxed out on every facet besides lowering the intake port another 2 degrees. The (considered to be unsafe) 75.5% exhaust port held the ring without incident, and the ring end gap that rides right on the chamfer of the B ports survived. (Maybe it was a blessing that millenium chamfered my transfers after all)

    Best of all, Engmod2t and my dyno results are all within .75 Hp for most of the curve with very small discrepancies that are probably a byproduct of small modeling errors. I had to do some tweaking to the temperature files from the default values, but after the first pipe was ran in the sim, the other 3 followed the trend and were an accurate representation of the dyno testing.

    We did multiple dyno runs on each pipe to verify consistency. Since this is for short duration drag racing each pipe also received what we called a cold test and a hot test. We placed a K type thermocouple in the center section of each pipe so we could heat the pipes to a consistent starting temperature before the controlled auto-run was started.

    Something that I noticed that I do not fully understand. The pipes made more hp throughout the graph on the cold start test, however the entire curve shifted to the right when performing a hot test pipe. The hot start pipes also smoothed out the curve much better.

    Here is my question. And I ask this cautiously because I now know that I am out to lunch on my pipe designs from where the end power goal is. The peak rpm is 3-400 rpm lower than expected, and what the engine wants.
    -I have been been under the impression for a while now that the hotter a pipe is the shorter it thinks it is, makes sense the power moved to the right on the hot start pipes. Why is power down with the hot pipe then? Confused I am.

  11. #37136
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    Quote Originally Posted by Condyn View Post
    Here is my question. And I ask this cautiously because I now know that I am out to lunch on my pipe designs from where the end power goal is. The peak rpm is 3-400 rpm lower than expected, and what the engine wants.
    -I have been been under the impression for a while now that the hotter a pipe is the shorter it thinks it is, makes sense the power moved to the right on the hot start pipes. Why is power down with the hot pipe then? Confused I am.
    Very often it is not the hotter pipe but the hotter exhaust port wall that heats up the short circuited / over scavenged gas that is plugged back into the cylinder by the plugging pulse, this has a lower density and thus less mass in the cylinder at export closure.

  12. #37137
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    Thank you, that is enough to put my wandering mind at ease.

  13. #37138
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    Quote Originally Posted by Condyn View Post
    -I have been been under the impression for a while now that the hotter a pipe is the shorter it thinks it is, makes sense the power moved to the right on the hot start pipes. Why is power down with the hot pipe then? Confused I am.
    To verify if your engine is running out of breath at higher rpm or if you are seeing the effect of the then fully warmed up engine, you can build a shorter version of that same pipe and do another cold and hot dyno pull. You should be able to model the temperature effect in EngMod, too if you play around with the temperatures a bit. On air cooled engines, the temperature and thus power differences between a cold and a hot engine are much bigger than on watercooled engines. Do you happen to have a thermocouple or an infrared gauge to measure the crankcase temperature?

  14. #37139
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    Quote Originally Posted by Haufen View Post
    To verify if your engine is running out of breath at higher rpm or if you are seeing the effect of the then fully warmed up engine, you can build a shorter version of that same pipe and do another cold and hot dyno pull. You should be able to model the temperature effect in EngMod, too if you play around with the temperatures a bit. On air cooled engines, the temperature and thus power differences between a cold and a hot engine are much bigger than on watercooled engines. Do you happen to have a thermocouple or an infrared gauge to measure the crankcase temperature?
    Thank you for the reply. I do not believe the engine is running out of breath just based on comparable setups that I am familiar with. I do not currently have any crankcase temperature monitoring, but I do have a spare thermocouple that I could fix to the case.

  15. #37140
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    Frits is right again. The nozzle size is dependent on the engine power , with one caveat.
    A bigger nozzle reduces the pipe pressure and thus the operating efficiency.
    This works in your favor lower in the powerband , as the return wave coming back too early has a reduced amplitude , thus it doesn't fuckup the power so badly.
    But of course no free lunch , in that what you gain down low you loose up top.

    Re the pipe temp and power loss - if the hotter pipe moves the power to the right ( as it should ) but you are seeing a loss at the higher rpm, then that means one of two things.
    There is an element of the tune that is not suited to the higher rpm , or the pipe is wrong for the new higher rpm ( or both ).
    EngMod is superb at sorting this stuff out.

    Maybe you need to settle on a strict test procedure that will then be taken to the strip , such that the beginning pipe/case temp is always the same.
    I did this years ago when designing pipes for Yamaha KT100 , the case temp was always started at the same level , and the final egt was always adjusted to match after every dyno run.
    Case and head temp are critical on an aircooled and can really lead you off on useless tangents if the process of testing isnt rigorous.
    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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