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Pinned Coil On Plug conversions - COP

Discussion in 'Tech Tips' started by Linkin, Aug 24, 2017.

  1. ShaneP

    ShaneP Well-Known Member

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    The coil does not need "energising" in preparation for a spark, in fact, the speed of change increases the voltage.

    Also, Linkin said 2-3kV on an empty chamber; the spark for ignition has to be greater.
     
  2. Frankster

    Frankster Grey Pride...Adventure before Dementia Staff Member Premium Member Ride and Events Crew

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    Yes, I misread @Linkin 's post. Sorry bout that.
     
  3. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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    Dont worry Frank .... my electrical understanding brain capacity ends here ... :D

    series parallel.jpg
     
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  4. Frankster

    Frankster Grey Pride...Adventure before Dementia Staff Member Premium Member Ride and Events Crew

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    @GreyImport these are for coils off late model Suzukis...GSXR I think. I've been looking for something to use on the VT250F COP Conversion and thought you might like to add these to the list. An auto electrician got these for me. Not sure of the Denso code for each, but I guess we can find them as we go.

    Model: 2001-2003 750 Suzuki
    Primary Resistance: 1.3ohms
    Secondary Resistance 11.5k ohms
    Length: 130mm

    Model: 1997-2000 600 Suzuki
    Primary Resistance: 0.4ohms
    Secondary Resistance: 5.55k ohms
    Length: 120mm

    Model: 1997-1999 750 Suzuki
    Primary Resistance: 0.3ohms
    Secondary Resistance 5.6k ohms
    Length: 118mm
     
  5. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Guys there's one possibility - replace the transistors for one with higher working current and get the coils with higher resistance to bring it into range - definitely doable on the Fzr - unsure about others

    Standard coil primary resistance
    https://2fiftycc.com/index.php?threads/resistance-values.5711/

    2.8 OHM

    From this page - got the transistor type 2SD2141
    https://2fiftycc.com/index.php?threads/looking-inside-fzr-250-cdi-unit.1998/
    Specs are 6A current (10A pulse)
    https://alltransistors.com/pdfview.php?doc=2sd2141.pdf&dire=_sanken-ele

    This one is a very good possible alternative
    15A current (30A pulse)
    https://www.st.com/en/power-transistors/bu941zt.html
    https://www.st.com/resource/en/datasheet/bu941zt.pdf


    These coils should be spot on with the higher power transistors installed and can be wired in parallel
    https://www.2fiftycc.com/index.php?threads/coil-on-plug-conversions.9631/#post-105103

    129700-3881,
    2.5-3.1 Ohm primary, 11.8K to 15 K Ohm secondary,
    Charge time ~ 3.1 ms (from internet search)
    length 139,7mm,
    actual coil without rubber insulator/seaL fitted 120.65mm, the silicon/rubber cap adds another 19mm length but slide's over the spark plug porcelain
    Used on the 1999, 2000 CBR600FX CBR600FY, (01 02) CBR600 FS1 CBR600 FS2
    2001, 2002 CBR600FR1 CBR600FR2, 2001-2006 CBR600 F1 CBR600 F6
    and the 2000-2003 CBR900 RRY, CBR900RR3

    I'm liking the look of this, it's be nice to tidy and update that ignition system
     
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  6. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    I am thinking of using the Ignitech CDI (real one not TCI) with COP. Seems like a good combination to me.
     
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  7. Frankster

    Frankster Grey Pride...Adventure before Dementia Staff Member Premium Member Ride and Events Crew

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    Why is it doable on the FZR and maybe not the others? They're all TCI units as standard, or does the FZR have a CDI? @maelstrom I think the Ignitech unit is also a TCI (from a conversation I had with @my67xr)
     
  8. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Yeah the FZR250's use's a TCI, the Ignitech Sparker Ignition's are also TCI's,
    but
    there is an Ignitech CDI available @Frankster , there's a basic non progammable unit ($74 US) and i think 4 other programmable one's ($110 US - $130 US)

    What are you trying to gain from running the coil's in parrallel @ruckusman ?
    Pretty sure there'd be an easier way of doing it if there was an advantage
     
    Last edited: Oct 27, 2018
  9. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    If you can open any of the other TCI's and give me the transistor codes I can check for an equivalent with a higher current capacity, if available - at that point it becomes doable.

    Ignitech make both TCI and CDI units - They basically wire in the same way and use coils with different resistance/inductance for the two systems.

    I just browsed some Ignitech docs on the FZR400 - wiring is simple enough, if someone out there has done it for say a ZXR400 then it would be simple enough to hopefully translate it to the ZXR250 for the wiring - then you'd need to create a spark map.

    It sounds simple enough in theory, but may be a little more complex in practice.
     
  10. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Realistically - just trying to ensure that both coils are getting full juice - given that it only involves replacing two transistors in the TCI which I have already opened and wiring parallel it's simple enough.

    Whether or not it yields benefits is another question entirely, so it may be effort for noguht.
     
  11. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    With my set up, the coil's wired up in series so 1&4, 2&3, mine has the same voltage going into both coils on each circuit


    If you are going to fit some higher amp transistor's into you TCI then i'm pretty sure the main power transistor will need to be uprated too
    Also the higher current running through the circuit's may require a few more uprated component's and possibly the track's on the circuit board
    The power wire's for the TCI will need to be upgraded from 14AWG (2.1mm core) to 10AWG (5.3mm core) as well as the cable's from the TCI to the ignition coil's
     
    Last edited: Oct 27, 2018
  12. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    All good points, if changing from series to parallel does have benefits then it's worth it - that is the part which is speculation.

    I'll check the connections into the coil charging transistors to see where they derive their power from, if it's direct from the loom or a common VCC trace that would need beefing up, if it's from a power transistor then it may need uprating also - could get tricky

    I do have an oscilloscope to look at the waveforms, not a bike which currently runs unfortunately.

    This is an interesting discussion about the COP conversion for bikes of similar vintage

    https://www.vmaxforum.net/showthread.php?t=13605

    They've done some good research, including the coil charging duration, charge current and energy dissipation.

    I need to research the effect of the inductance and take measurements of the OEM coils for comparison
     
  13. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    There's a main transistor in the middle of the TCI, i reckon that power's the other 2 transistor's
    B1015 in the middle here


    [​IMG][​IMG] [​IMG]
     
  14. ShaneP

    ShaneP Well-Known Member

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    I looked at ignitech website and thought about making an EFI zxr250.... Might be $1000 to do it, though. Might be just as well to get a 600 EFI, and turn down the fuel pressure - speed limiter kicks in about 14k rpm, though. I have too many projects before thinking about this one.
     
  15. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Looking at the traces on that board - the collector on the power transistors connects directly to the loom, I suspect the coils, the transistor base looks to connect to two signal transistors and to the EPROM - cannot discern where the transistor emitter line connects - there may be a power diode or something which protects the electrical system from noise and voltage spikes - that component if present might need uprating

    The 2SB1015 is only rated to 3 amps which using V=IR wouldn't be sufficient of running the coils which should hypothetically draw ~4.5 - 5 amps for coils with 2.8 ohm resistance

    It would be great to find the spec sheet for that EPROM, but I remember all of my searches years ago were fruitless unfortuately
     
  16. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    To save all the mucking around inside the TCI i'm pretty sure you could use something like the Bosch module # 0227 100 211
    and run it off the negative switching from the TCI
    Or another style ignition module

    eg

    134479d1501884623-cosworth-managment-coil-on-plug-4channel.jpg
     
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  17. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    That looks to be a pair of NPN power transistors in an easy to wire up package, I think that if you took the Base input to the TCI transistors you'd get your signal line for triggering.

    You'd still have to de-solder the rest of the power transistors, which is the same as replacing them.

    Thinking on it, I wouldn't be surprised if the TCI power transistors are connected to a relay, I'll have a look at mine tomorrow and try and trace the wring loom.

    We don't have a legible FZR250 schematic anywhere do we?
     
  18. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    I would leave the original transistor's in the TCI and just use them to trigger the Bosch Igniter
    The 2x 2SD2141 transistor's in the TCI would have a much easier life only having to switch 1/4 or the power.
     
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  19. Frankster

    Frankster Grey Pride...Adventure before Dementia Staff Member Premium Member Ride and Events Crew

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    So, that diagram you posted is if we want to run the COP setup in a parallel configuration, yes?

    What happens to the primary and secondary resistance ranges used in the current series setup? e.g. if, with a waste spark configuration, the manual says Primary is 2.5-3.2ohms and the Secondary is 15-18k, do we halve those values when selecting the Coils? E.g. a COP Coil with 1.2-1.5ohms Primary and 8-9k Secondary?
     
  20. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    To run the coils in series you can halve the coil primary resistance as they are added to give to total resistance - total resistance RT = R1 + R2

    To run coils in parallel you require coils with as close to similar resistance as the original single coil and uprate the power transistors to sustain the additional current because parallel coils will effectively halve the resistance.

    1/RT = 1/R1 + 1/R2

    I would think that secondary resistance for each coil close to the original resistance will work, but I don't know enough about inductance to justify that statement with mathematics.

    There may be no advantage to running them in parallel and I am thinking of a way to test it that doesn't involve a dyno or something to measure spark power at high RPM

    If I can put the oscilloscope on the coil to measure dwell time at different RPM it may give a clue if dwell time diminishes at higher RPM.

    This is a good read on dwell time - more is not necessarily better - so matching the coil resistance to the OEM would be advised.

    Interesting to see it is 2ms for the RVF/VFR400 which means that even at say ~18K RPM with a wasted spark system the 3ms revolution time between pistons 1&4 & 2&3 there is sufficient dwell time if it is similar to the FZR & ZXR ignition systems

    http://www.400greybike.com/forum/viewtopic.php?t=36399
     
    Last edited: Oct 29, 2018

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