scootz
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| posted on 6/6/12 at 09:09 PM |
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Changing COP to Wasted Spark
I'm looking to use an Omex 500 on the BMW bike engine (boxer-twin with 360 degree firing order). One of the things I'm going to have to
change is the current coil-on-plug ignition to a wasted spark set-up.
Can anyone recommend a suitable coil option for use with the engine / ECU combo?
Also, the ECU works semi-sequential injection... am I right in thinking that this will be fine on a flat twin with a 360 degree firing order?
Thanks in advance.
[Edited on 6/6/12 by scootz]
It's Evolution Baby!
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matt_gsxr
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| posted on 6/6/12 at 09:57 PM |
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Dynatek DC6-1 would work as a coil (2 outputs so good for wasted spark) and I have had good experience with dynatek (although I swapped to Ford
because I mistakenly thought the coil was at fault, which still annoys me).
Not sure what your ECU can drive though.
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ashg
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| posted on 6/6/12 at 10:03 PM |
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Why do you need get rid of the cop's you can fire them semi sequentially. if the omex only has support for wasted spark units all you need to
do is build a simple circuit with a couple of transistors so you can go from a 12v trigger signal to a 5volt signal. personally I would have thought
omex would support cop's even in wasted spark mode as they are easier to fire than a standard coil if they have built in ignitors
[Edited on 6/6/2012 by ashg]
Anything With Tits or Wheels Will cost you MONEY!!
Haynes Roadster (Finished)
Exocet (Finished & Sold)
New Project (Started)
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scootz
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| posted on 7/6/12 at 08:03 AM |
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Cheers fellas.
I'm only going by what the Omex guy has said to me Ash... "the 500 doesn't do COP - you will need to change to a wasted-spark
set-up".
It's Evolution Baby!
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lsdweb
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| posted on 7/6/12 at 12:03 PM |
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Scott
Be careful of using the existing COP setup with wasted spark as you'll be firing the COPs twice as quickly as they are designed for.
I did this with my R1 and Emerald a few years ago and always had concerns about fried coils.
Regards
Wyn
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scootz
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| posted on 7/6/12 at 12:09 PM |
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Thanks Wyn!
It's Evolution Baby!
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coyoteboy
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| posted on 7/6/12 at 03:59 PM |
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FWIW I run two bike engines on COP wasted spark (megasquirt) and as yet haven't fried a coil despite running them up to 15Krpm and up to 3ms
dwell - don't even get hot on the test bench. That said, that's not an "it'll work" answer, just "it'll
probably be fine".
[Edited on 7/6/12 by coyoteboy]
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scootz
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| posted on 7/6/12 at 04:11 PM |
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Cheers.
It's Evolution Baby!
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matt_gsxr
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| posted on 8/6/12 at 08:00 AM |
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quote:
Originally posted by scootz
Cheers fellas.
I'm only going by what the Omex guy has said to me Ash... "the 500 doesn't do COP - you will need to change to a wasted-spark
set-up".
I'd ask again. The 500 has only 2 drivers, so on a 4 cylinder engine it wouldn't be able to drive COP "properly" (i.e.
non-wasted spark). This might be what he meant.
I would have thought that with your set-up you should be laughing, as long as the COP can handle it.
By the way, what cam trigger do you have on the BMW? If you fitted a 36-1 wheel to the cam then you could drive the OMEX from that and not have to
run your COP wasted-spark (with the possible overheating, undersaturating concerns).
You would have to live/deal with the RPM being scaled by a factor of 2, but apart from that I would have thought it would work.
I don't know anything about OMEX 500 beyond what I just read in the manual ( http://www.omextechnology.co.uk/500v3.02.pdf )
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ashg
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| posted on 8/6/12 at 08:14 AM |
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i run my cop's in wasted for over a year before i went to sequential. woulnt yo be better off selling the 500 and getting a 700, to me it
seems strange that you would want to down grade from what was a sequential setup to wasted spark.
Anything With Tits or Wheels Will cost you MONEY!!
Haynes Roadster (Finished)
Exocet (Finished & Sold)
New Project (Started)
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scootz
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| posted on 8/6/12 at 12:31 PM |
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Thanks again guys... it's a 58-2 trigger wheel (which I'm told the Omex should be happy with).
I also had another wee chat with their technical guy Andy (top fella) and it would seem we got a bit conzussled... he thought it was a 4 cyl Boxer
engine... not a twin. So he's asked me to measure the primary resistance across the coil... I wish I had a digital meter as my B&Q one is
crap!
It's Evolution Baby!
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scootz
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| posted on 8/6/12 at 12:51 PM |
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My MM is telling me I have a primary resistance of 1.8 ohms across the +ve and -ve of the coil. Had a chat with Omex again and they confirm I will
indeed have to change to twin-unamplified wasted spark coils 
Guess Dynatek will be the guys to speak to now!
PS - Why am I using the 500? Because I only want my engine to suck, squeeze, bang and blow, and I got it at a price where it makes sense to try it!
It's Evolution Baby!
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matt_gsxr
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| posted on 8/6/12 at 01:00 PM |
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You could use stock Suzuki coils of the old-skool era. I.e. gsxr1100 1980-1997 or from a gsxr750.
But I know you like your bling, and the stock leads might not be long enough given the distance between the plugs on your engine.
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scootz
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| posted on 8/6/12 at 02:57 PM |
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Thanks Matt. I'll check it out.
In short, I need an un-amplified coil to fire 2 spark plugs simultaneously and be compatible with an ECU that typically deals with 0.5 - 1.0 Ohms as
it's primary resistance.
It's Evolution Baby!
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coyoteboy
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| posted on 8/6/12 at 03:09 PM |
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2007 CBR600RR coil on plug coils are 1.6ish ohms primary resistance, two pin, can be wired in parallel, still give you 0.8ohms primary and gives you
nice COPs. I've got a set of 4 that I was going to put on my Celica but haven't yet if you want measurements.
[Edited on 8/6/12 by coyoteboy]
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matt_gsxr
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| posted on 10/6/12 at 11:04 AM |
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quote:
Originally posted by scootz
Thanks Matt. I'll check it out.
In short, I need an un-amplified coil to fire 2 spark plugs simultaneously and be compatible with an ECU that typically deals with 0.5 - 1.0 Ohms as
it's primary resistance.
I can post you a standard gsxr coil FOC that does what you need and you could use for prototyping. Resistance is 1.9 Ohm.
Might save you buying something that you then have to sell on for less money.
I would have guessed that having more resistance is only going to make life easier for the ECU (more resistance=less current).
Dyna coils come in different resistance, http://www.dynaonline.com/skins/products/accessories/Dyna_Coils/
U2U me an address if you want one, I have a few and they are just wasting shed space.
Matt
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scootz
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| posted on 10/6/12 at 11:21 AM |
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Thanks for the kind offer Matt... I really appreciate it!
However, I've bought a DC11-2 from Dynatek (I should hopefully get the bulk of the cost back on the sale of the OE BMW coils).
Link To DC11-2 Spec
[Edited on 10/6/12 by scootz]
It's Evolution Baby!
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matt_gsxr
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| posted on 16/6/12 at 09:08 AM |
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no worries, I look forward to hearing how it goes.
Matt
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