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Thread: ESE's works engine tuner

  1. #27046
    Join Date
    2nd March 2013 - 15:04
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    CBX125F NS50F NS90F NS-1
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    Quote Originally Posted by TZ350 View Post
    Great effort, very impressed with the RV conversion. My favorite RV timing on the 125 is, inlet opens 145 BTDC and closes 85 ATDC. Opening is 145 std Suzuki timing for a GP125 and 135 for a GP100.
    Thanks for that Rob, much more development to do though. Wow, that stock GP125 opening is really early, but I guess they don't rev much.

    I suspect that with your EFI you can get away with ealier opening than suggested for a carburetted engine as the reduced intake air velocity would not have the repercussions for fuel flow that you get with a carb.
    I'm only guessing really. Dyno will tell you.

  2. #27047
    Join Date
    14th April 2011 - 23:44
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    2008 Yamaha fino
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    Bangkok
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    Quote Originally Posted by Lightbulb View Post
    I think the only pumping losses are those pumping money into the project are realising losses.

    I am seriously thinking that if they really did have anything really substantial, it would be out by now and
    be blistering track records everywhere. But that has not happened, sadly. We get strung along all the time
    with little miss leading things, time and time again. We are suckers for new tech and most here have a true desire
    to learn more about a very simple in principle engine. Crowd development may be the way to go. They got a patent
    application in place, but still don't share anything. They set a track record against 4s renta karts and we are supposed to be impressed.
    I have seen a one time picture from a tacho at like 28100 rpm. Then told it has passed 30 k more than once. But like any monsta
    story, no video, or audio for that matter. 1900 rpm is a lot at that level. Look at a 6.5 cc methanol engine. Very difficult to go from 34k to 35k
    rpm, and they want us to believe it can easily do 30k with a 125. Like some have said, very doubtful for any length of time, without super materials that
    would put the engine price above 30k to get made.
    Those 'pumping in the money' must really be worried now.....
    No races won, no engines sold, how will this end?
    In a very bad way I think!

  3. #27048
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    5th April 2013 - 13:09
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    zuma50
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    illinois
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    TZ350, we rev 250 4 strokes to 15,000rpm all day with a single injector in the throttle body. I'm comparing apples to oranges I know, but still... was shocked to think you need 3 injectors for 13k.

    I'm also very interested to hear more of your findings in your NSR250 porting. You actually lost power by opening up the ears of the exhaust port? You're either transfer limited, or major short circuit going on A transfers to ex port. You may find it beneficial to "bowl" out ex port right after window.

  4. #27049
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    5th January 2007 - 14:58
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    motocompo
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    Quote Originally Posted by jonny quest View Post
    TZ350, we rev 250 4 strokes to 15,000rpm all day with a single injector in the throttle body. I'm comparing apples to oranges I know, but still... was shocked to think you need 3 injectors for 13k.
    .
    Applying some quite basic arithmetic, 13,000 rpm on a two stroke, equals roughly 26,000 rpm on a 4 stroke as regards injector cycles.
    Maybe that goes some way to help explaining the anomaly.

  5. #27050
    Join Date
    18th May 2007 - 20:23
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    RG50 and 76 Suzuki GP125 Buckets
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    Auckland
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    Quote Originally Posted by sidecar bob View Post
    Applying some quite basic arithmetic, 13,000 rpm on a two stroke, equals roughly 26,000 rpm on a 4 stroke as regards injector cycles. Maybe that goes some way to help explaining the anomaly.
    Absolutely

    Quote Originally Posted by jonny quest View Post
    I'm also very interested to hear more of your findings in your NSR250 porting. You actually lost power by opening up the ears of the exhaust port? You're either transfer limited, or major short circuit going on A transfers to ex port. You may find it beneficial to "bowl" out ex port right after window.
    Yes my first effort at porting the NSR cylinder lost power. And I think you are right about the reasons. I tried leveling the top of the exhaust port off by eye but totally stuffed up the exhaust port timing, got something like Ex opens 74 ATDC and to get the timing anywhere sensible I trimmed 2mm of the bottom of the barrel. The Ex was then 78.5 atdc and trans 122. To get the trans back to 113 I angled the A's up at 25 deg and the B's at 15 but the whole thing was a shambles.

    So I started again.

    Click image for larger version. 

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    Quote Originally Posted by jonny quest View Post
    TZ350, we rev 250 4 strokes to 15,000rpm all day with a single injector in the throttle body. I'm comparing apples to oranges I know, but still... was shocked to think you need 3 injectors for 13k.
    Yes, three physical injectors but there are actually only two "logical" injectors, one big one small. The two "physical" injectors in the B ports are there for symmetry of fuel distribution and are fired together as one Logical injector. I use three physical 124g/min injectors but the EFI CPU sees only two logical injectors, a 124g/min slow speed injector and one 248g/min high speed injector.

    But it is not about injector size but time available to get the injecting done. If you only have half the time, then you need an injector twice the size to get the job done. And you need a small one for tune-ability when there is plenty of time like <9k 2T rpm (equivalent to 18k 4T rpm) and a much bigger one to deliver much the same amount of fuel when time is getting short like above 10k.

    The reason you can't use the big injector for slow running is because an injector must be turned on for a minimum amount of time to get it completely open and controllable. And a big injector just spills to much uncontrolled fuel while it is opening for idling speeds and small throttle opening.

    15,000 4T maxed out rpm "Time" for an injection cycle is just about where my 2T is starting to come on the pipe and get going. A 4T has twice as much time to get things done so only needs an injector half the size of a 2T, ie something about the size of my slow running injector.

    It is "Time" not injector size that is the real issue with EFI.

    Quote Originally Posted by jonny quest View Post
    ... a single injector in the throttle body.
    Another issue with 2T EFI and throttle body injection is that unlike a carburetor which adds fuel to the air stream all the time, regardless of whether the air is being sucked in or blown back out of the crankcase ie fuel standoff.

    A fuel injector squirts fuel in discreet blobs. And is just as likely to add all the fuel to the air stream as its blown back out as it is to the air stream being sucked in. So there could easily be rpm patches where you could wind up with little fuel at all in the crankcase.

    This is less of a problem with transfer port injection. Where the bulk of the fuel is concentrated in the transfer duct and not the inlet tract where it can be more easily ejected. And will be one of the reasons why 2T EFI can show improved fuel efficiency over a carburetor.

    And another reason for injecting into the B transfers is that the bulk of charge short circuiting happens from the A ports and if there is little fuel in the short circuiting air then the motor is cleaner and more fuel efficient. Another win over the carburetor which would have loaded all the crankcase air with fuel.

    With a carburetor all blow back and short circuiting air loses fuel and pollutes the environment, with 2T EFI not so much as the air lost has little fuel in it.

  6. #27051
    Join Date
    20th January 2010 - 14:41
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    husaberg
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    Quote Originally Posted by jonny quest View Post
    TZ350, we rev 250 4 strokes to 15,000rpm all day with a single injector in the throttle body. I'm comparing apples to oranges I know, but still... was shocked to think you need 3 injectors for 13k.

    I'm also very interested to hear more of your findings in your NSR250 porting. You actually lost power by opening up the ears of the exhaust port? You're either transfer limited, or major short circuit going on A transfers to ex port. You may find it beneficial to "bowl" out ex port right after window.
    AS well as what Bob and Rob have mentioned
    Four stroke 4 cylinder maps have pretty basic requiements four stroke twins are a lot more fussy two stroke are a less forgiving again
    Quote Originally Posted by Katman View Post
    I reminder distinctly .




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

  7. #27052
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    28th November 2013 - 21:58
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    Dawes Jaguar
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    UK
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    Hope this link works, as it's from an email subscription, but it should go to a page from Dirt Rider magazine reviewing the EFI strokers from Husky and KTM.
    http://links.mkt3362.com/servlet/Mai...NgS2&mt=1&rt=0

  8. #27053
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    16th January 2016 - 04:20
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    Quote Originally Posted by Lightbulb View Post
    I have seen a one time picture from a tacho at like 28100 rpm. Then told it has passed 30 k more than once. But like any monsta
    story, no video, or audio for that matter.
    Maybe they had the tacho in 4 stroke mode and they are too deep into the rabbit hole to admit it now

  9. #27054
    Join Date
    18th May 2016 - 19:19
    Bike
    Aprilia rs 125 2000
    Location
    France
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    Quote Originally Posted by jamathi View Post
    RSW and RSA ducts were the same.
    Roof angles did not change since 1995
    The RSA cylinder had improved cooling.
    Hello mr jan, you say that the transfer times have been unchanged so that means that it was the right compromise debit, pressure, opening time? How to find this flow balance, pressure? Is what the transfer flow corresponds to The intake capacity? is what the port transfers match the pipe pulses? thank you

  10. #27055
    Join Date
    8th February 2007 - 20:42
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    TZ400
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    tAURANGA
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    If you look at the STA numbers of an Aprilia cylinder it appears that the transfers are way ahead of the Exhaust as far as power making capability.
    But if you look at the reality of the Exhaust Cd, with its huge radius on the top edge, that effectively begins to open above 200* duration with the port
    roof itself down at 196* then it becomes clear that all the work done by hand in the R&D dept to match the Blowdown flow numbers with the transfers
    gave a highly synergistic scenario.
    Raising the transfers lost power - as did lowering them.
    And the scavenging pattern along with the timings had been optimized quite early on.
    The same with the Aux ports - any higher or wider lost power.
    All dimensions being tested on the dyno and the best results kept in production - a slow to achieve, but highly accurate method for gaining GP winning power.
    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.

  11. #27056
    Join Date
    14th April 2011 - 23:44
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    2008 Yamaha fino
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    Bangkok
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    Quote Originally Posted by jellert View Post
    Maybe they had the tacho in 4 stroke mode and they are too deep into the rabbit hole to admit it now
    HAHA, probably....

  12. #27057
    Join Date
    10th February 2005 - 20:25
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    1944 RE 1
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    Auckland, New Zealand.
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    Quote Originally Posted by guyhockley View Post
    ....... a page from Dirt Rider magazine reviewing the EFI strokers from Husky and KTM.
    Guy, our Neil (Flettner) has had a Kawasaki Bighorn operating successfully on fuel injection for yonks, we are proud of him for his perseverance in achieving that!

    update:- also TZ is into it big time as well! - very forward thinking.... us Kiwis!
    Strokers Galore!

  13. #27058
    Join Date
    18th May 2007 - 20:23
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    RG50 and 76 Suzuki GP125 Buckets
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    Click image for larger version. 

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    Cylinder and under piston injector slot done.

    So if I can get the engine back together during the week it is looking hopeful for a dyno run next weekend.

  14. #27059
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    18th May 2007 - 20:23
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    Because someone asked.

    There are three physical injectors but there are actually only two "logical" injectors, one big one small.

    The two "physical" injectors in the B ports are there for symmetry of fuel distribution and are fired together as one Logical injector.

    I use three physical 124g/min injectors but the EFI CPU sees only two logical injectors, a 124g/min slow speed injector and one 248g/min high speed injector.

    In broad terms, because there is much the same amount of air consumed per revolution. Both 124 and 248 injectors deliver the same amount of fuel per revolution.

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    Both 124 and 248 injectors deliver much the same amount of fuel per revolution.

    Because the lower speed 124g/min injector has 10ms to do the job.

    And because the higher speed 248g/min injector only has 5ms to do the job it needs to be twice as big.

    Time available dictates the injector sizes.

  15. #27060
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    20th April 2011 - 08:45
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    Quote Originally Posted by TZ350 View Post
    If the standoff was reduced and as jetting is not a problem with EFI would it be a benefit to opening a RV inlet much earlier, or even before BDC like a 4T or is there some other limit? Interested because with my bike running EFI for jetting and using the variable inlet area system that I have for suppressing the standoff I would be very interested in how much earlier people think the RV inlet opening timing could be usefully advanced too.
    If a clear suction signal to the carburetter is no longer needed, you could start opening the RV at about 20° after BDC at max.torque rpm, assuming sufficient transfer angle.area, and even earlier at lower rpm's.
    Opening the RV as soon as the crankcase pressure has dropped to the same value as the pressure upstream of the RV, will prevent the case pressure from dropping much further, which would slow down and eventually reverse the transfer flow.

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