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Project Fuel injected ZXR project (Where'd 2 months go?)

Discussion in 'Your 250cc Projects' started by DamnitLaverty, Nov 19, 2020.

  1. Mike Green

    Mike Green Active Member

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    I would make a jig to spin the trigger disc and monitor the output of the sensor using an osciloscope. I expect you will need good quality cable, at least, to maintain the trigger waveform at high speed. your ECU also needs to be able to monitor the frequency. From my own experience you really don't need so many teeth. Yamaha only had 4 teeth for the standard ignition triggering, and fuel injection is way less critical as far as timing goes.
     
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  2. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    The ECU spec should give guidance on signal timing - remember this is all about how much time to read the signals is required, assuming they are clear and distinct

    So at say 17K RPM is 283 Revs per second X 36 is 10.2KHz - that seems to be a lot, for humans anyway, easy for electronics, 10 degrees of resolution is great, but is it necessary.
     
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  3. Mike Green

    Mike Green Active Member

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    IF the crank rotated at a nice even rate there would only need to be one tooth. The software could easily calculate where the crankshaft was at any time between triggers. The problem is that crankshafts don't rotate at a nice even speed. Every single crank rotation has a range of rotational speeds caused by a piston coming up on compression versus a piston going down on the power stroke. This variation is the reason why there is a cush drive in the clutch. The variation is also the reason for 36-1 trigger wheels. The rate at which the trigger pulses are generated tells the ECU the instantaneous crank speed but probably more importantly also allows the ECU to determine the crank location more precisely at any point in time. Given that there are probably fairly consistent variations in crank speed and variation from the calculated located for a steady constant rotation rate, within each revolution, it's entirely possible to map the timing to compensate.
     
  4. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Excellent points, obviously the software is capable of interpolating between trigger signals.

    Thinking on it, if a 36-1 works, that's ideal - 10 degrees of resolution is excellent.

    However if it's unreliable or too much at high RPM, would you best require at least three which span the range of maximum advance down to minimum advance?

    That's at least a known range

    I've seen the ignition advance curve for the ZXR250 somewhere, doesn't seem to be in this thread.

    Here's some info @Frankster seems to be a font of knowledge on the TCI's and their ignition curves

    https://www.2fiftycc.com/index.php?threads/zx2r-1989-exhaust.10446/#post-122288

    So a range from 10 degrees to 38 degrees in that curve - gives 28 degree range, which is incredibly close to 13 tooth as
    13*28=364, but 13 isn't divisible by 4, so would you increase it to 16 or reduce it to 12
     
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  5. DamnitLaverty

    DamnitLaverty Doing things the hard way since '78! Premium Member

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    Damned fine question, dude. I think as long as its got a starting tooth, it can interpolate, no?
     
  6. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Yes absolutely, I'd say the where the signals are in relation to the advance is as important as the number - no proof of this, it's just logical, one at maximum advance would be mandatory because that's where it's likely slowing approaching TDC compression whilst at end the end of one combustion downstroke on an adjacent piston pair.

    I think there has to be an optimum number for accuracy.

    The ZXR curve has that spike at 8K RPM 37-38 degrees, but then drops back to 26 degrees, with static being 10 degrees
    I'd say 12 degrees between signals would be ideal which would be 30 teeth
    38 - 12 -> 26 -12 -> 14, so the lowest advance would need to be interpolated to give 10 degrees, but it doesn't stay there long which is good and you'd have on at 2 degrees BTDC

    We can know the curve, which on the FZR250 is based upon 4 signals, is it the same for the ZXR250?
    The fact that they've managed to program a curve strongly suggests they've got some fine calculations occurring which do interpolate the engine speed, and I suspect that they've also programmed the pulsing motion of the crank in the original TCI's - it's impressive
     
  7. Mike Green

    Mike Green Active Member

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    The trigger locations are not important as far as I know. The only thing Link suggested was not to have the cam trigger at the same time as a crank trigger. Everything else was programmable. Probably an idea to keep triggers away from ignition events as well if possible. That's a bit hard with the timing curve of course, especially if you have a high tooth count on the trigger disc.
     
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  8. Frankster

    Frankster "Play stupid games, win stupid prizes" Staff Member Premium Member Ride and Events Crew

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    So, when do you get back to the EFI & Turbo project?
     
  9. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Guys FWIW - I've been keeping myself occupied during lockdown seriously contemplating an EFI conversion, on a YZF600r to begin with...

    Anyway, on my travels through the internet, I've stumbled across the possibility to modify OEM ECU fuelling and advance maps, among other things.

    Where this gets interesting is that, one of the best developed ECU's is for the Suzuki Hayabusa - Now those guys are bonkers, nuts in a good way, they're doing nitrous, they're doing turbo, they're doing both at the same time.

    What it does potentially, is to remove the biggest barrier to entry for EFI and the rest, because you can get, if fortunate enough, the entire loom an EFI system from a wrecked bike, it doesn't have to be a Busa 2002 -> onwards, GSXRs - 600, 750 & 1000 of the correct age - roughly 2007 - 2011 and Busa firmware can go onto these ECU's, and for less $$ than a high spec ECU

    The various ignition and fueling maps go to 16000 RPM - that range can be modified with correct program, which I am researching

    You can likely get the whole shebang, loom, ECU, sensors, coils, etc for less than the cost of just a good spec standalone ECU

    One special element is that these ECU's run 4 separate ignition channels, AND 8 separate injector channels, from what I have read, they do BOTH sequential AND staged injection, from the primary at low revs UP TO the secondary spray injector at high RPM

    Anyway checkout "Ecu editor" - it's free and comes with the various ECU binary files of the above models in built into the software itself to see what's what http://ecueditor.com/

    You may gain some insight just by looking that the included tables regarding boost fueling tables, nitrous ignition retard settings etc etc

    It can log a running engine, do fuel table modification from logged fuel tables etc, and the cable hardware to connect from somewhere like https://boostbysmith.com/ is very reasonably priced for those avoiding doing their own cabling

    https://www.hayabusa.org/ and http://suzukihayabusa.org/ both have good info

    Have fun and don't blame me if this becomes a rabbit hole, down which you disappear - you have been warned...
     
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  10. DamnitLaverty

    DamnitLaverty Doing things the hard way since '78! Premium Member

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    The truth of it is that the last few months have done a number on me. I'm taking a couple months away from serious wrenching. I might get out and drain the VP108 out of the tank and put some 92 back in, rejet to stock, and put an airbox on- only because both my bikes are down right now and I'd like to ride one.

    I think I'm taking a at least 2 month break from all my projects. I spent the last year and a half hiding from life in my garage and I need to really refocus on me instead of burying myself in projects. The Falcon and the ZXR are gonna have to just build up some dust for a bit I think while I straighten myself out.


    See now, this is really really compelling. Shame I'm so far down my current path, this has some real potential!
     
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  11. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Yeah I know the feeling, I actually haven't had a rideable bike since I got knocked off of my Gixxer 750 and it got written off, that will soon change

    It all gets in the way, things get in the way of other things which get in the way of other things, do what you need to do for you - that is important!

    You know what, there's no harm in grabbing just the free software and taking a peek - it's a $0 upfront cost and is perfect for those times when TV just ain't cutting it, that was what I did...
     
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  12. Frankster

    Frankster "Play stupid games, win stupid prizes" Staff Member Premium Member Ride and Events Crew

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    The truth of it is that the last few months have done a number on me. I'm taking a couple months away from serious wrenching.

    That's a good call. Enjoy your break.
     
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  13. Frankster

    Frankster "Play stupid games, win stupid prizes" Staff Member Premium Member Ride and Events Crew

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  14. Mike Green

    Mike Green Active Member

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    . It's ready to race, I've joined the AMCC and will be taking it to the next meeting after lockdown. No turbo yet
     
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  15. Mike Green

    Mike Green Active Member

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    Originally I installed an Ecotrons kit for a GPz250. The throttle body pushes straight in. You would need 2 throttle bodies on a FZR but I have seen a really cool way of connecting them together. The Ecotron system is very reasonably priced. Despite their assurance just prior to me purchasing I doubt they will handle the revs. You certainly can't map above about 14,000rpm I think it was. I had a few niggly problems which they were helping with initially but after a while the lack of support became too much and I bought a Link G4+ Atom. This is a great bit of gear and the support is outstanding. Configuring the Ecotrons for anything odd is very difficult. The documentation is not well written with english obviously not their primary language and the software is not versatile. They have minimal onboard RAM and don't log run data which can be very useful if you are chasing issues. I'd say they would be good if you have the type of bike they support, simply plug and play.
     
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  16. DamnitLaverty

    DamnitLaverty Doing things the hard way since '78! Premium Member

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    So, I’m not ready to do anything with it yet, but I’m real excited it’s here!!

    MCM commissioned a tiny BOV for their postie bike, GFB ran a few extra off. DHL just got it here from yall’s neck of the woods.

    Much like the ZXR- it’s like a real one but smaller.

    Solves a lot of packaging issues, tell ya what!
    4B8C3EC4-D1AA-434F-B28E-3643C3C44F9B.jpeg
     
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