Fireblade - Coil on Plug Conversion
gingerprince - 10/7/13 at 08:42 PM
So I've had an ongoing issue with my 918 'blade in my Indy, where it's been having dodgy tickover issues at idle when hot. Have been
ruling a few things out by trial and error, and next on the list was coil packs. I had already replaced HT leads, plug caps and plugs which
didn't fix the issue. So, I needed to get a replacement coil pack or 2, which are going for about 30 quid on ebay.
Bit more research, and I came across the concept of converting from traditional coil pack/HT leads. This would let me rule out coil packs, and
potentially cheap HT leads leaking, and give me a more modern ignition system - for about the same price as just ruling it out.
So I found a set of stick coils, complete with sub loom on ebay for 35 quid delivered, butchered the loom, et voila: -
Coil Pack Replacement
So in theory I should have fewer issues due to old coils/HT leads, and more reliable spark.
As it turns out, an extended blat this evening reveals it hasn't fixed the issue, but that's for another thread 
I have saved a net 200g in weight though 
ashg - 10/7/13 at 09:04 PM
how are you controlling the dwell on them it wont be the same as the previous coil packs and will eventually end in failure.
MikeRJ - 10/7/13 at 09:47 PM
quote:
Originally posted by ashg
how are you controlling the dwell on them it wont be the same as the previous coil packs and will eventually end in failure.
Not to mention each coil driver is now driving two coils in parallel.
gingerprince - 14/7/13 at 01:44 PM
quote:
Not to mention each coil driver is now driving two coils in parallel.
The coils are wired in series, so the resistance for each pair is the same, so I don't believe there's any risk to the ECU.
quote:
how are you controlling the dwell on them it wont be the same as the previous coil packs and will eventually end in failure.
I'll be honest, I don't really have a clue what that means I've pretty much just followed a couple of articles, such as the one
below, and an article in Practical Sportsbikes magazine.
http://www.rrzone.com/forums/showthread.php/5894-STICK-COIL-MOD
However having done a bit more reading on the subject now (gate, horse, bolted etc) I think I understand it a bit. I guess the issue is, if the new
coils charge quicker than the old coils, they may overheat and break down. Obviously quite a few people have done this mod, so it must work (and
seems fine so far), but thoughts as to why I think it's OK from what I've read are: -
* They're wired in series, so the resistance as the ECU sees it is the same - so shouldn't break that.
* The coils are designed for individual firing in their original installation, rather than wasted spark, so in theory they will only have at maximum
half the amount of time to build up charge in this installation, depending on how the ECU controls dwell time in the old ECU.
* Since they're wired in series, the potential is divided between them, which means they're charging with only 6v not 12v, which again
will reduce the spark.
Based on the above, I'm deducing that if anything I'm more likely to have issues with not enough dwell time at high RPM (due to firing twice
as often, and lower voltage) rather than running too hot and breaking down. Haven't felt any evidence of this though - not sure whether
it'd be obvious or subtle?
I won't be chucking the old coils away though - the modification hasn't fixed my idle, so I think my old setup was probably OK. What I may
do is make a mount so I can easily swap between two configurations by remounting where the original coils go, so I can do a side-by-side "seat of
the pants" dyno to see if I can feel any loss of power due to unsufficient spark at high RPMs.
Thanks for pointing this out - it's generated some more reading potential in any case!
mef - 26/7/13 at 09:46 AM
Running your coils in series and hence only 6v across each primary will seriously reduce the spark quality, ie 1/4 of the power of a coil run on 12V.
Not ideal when pulling high revs! You should ideally run a 4 channel amp module to drive them individually but fired in pairs. An amp such as the
Bosch 211 would be ideal for this application, wire the inputs in 2 pairs (this is assuming your ecu will drive an external amp) see
http://www.microsquirt.info/Bosch_211.htm
Martin
[Edited on 26/7/13 by mef]
BaileyPerformance - 26/7/13 at 10:26 AM
stick with coil pack, but use a gen1 Ford coilpack with car leads (you can make them up using an XR2i set)
A good coilpack is better then COP, we have proven this on a 2008 Hayabusa in a grass car, the stock bike COPs do not produce the same amount of
energy as a stock Ford coilpack plus over dwell is not so critical on the coilpack but is critical on COP due to there hot location. Therefore you can
run slightly more dwell to get a fatter spark on the coilpack.
www.baileyperformance.co.uk
olimarler - 26/7/13 at 10:31 AM
I've been thinking about doing this too.
The honda cbr forum a lot of them are doing this mod with very good success.
Oli
mef - 26/7/13 at 10:59 AM
quote:
Originally posted by BaileyPerformance
stick with coil pack, but use a gen1 Ford coilpack with car leads (you can make them up using an XR2i set)
A good coilpack is better then COP, we have proven this on a 2008 Hayabusa in a grass car, the stock bike COPs do not produce the same amount of
energy as a stock Ford coilpack plus over dwell is not so critical on the coilpack but is critical on COP due to there hot location. Therefore you can
run slightly more dwell to get a fatter spark on the coilpack.
www.baileyperformance.co.uk
Yes, you dont get anything for free, the quality of the spark is directly proportional to the amount of copper wire and magnetic core in the coil, in
this case bigger is definitely better! a puney cop just cant produce the fat spark of a proper coil!
Martin
Brackers - 13/9/15 at 04:11 PM
Hi, I think I might have a similar problem - 1997 fireblade in Indy, been off road for over a year, now running and started up first time.
Fine ticking over and starts to warm up - giving a bit of throttle and sounds really smooth. After about 3-4 mins with engine warming up, as soon as
you give any throttle at all, even slowly rolling it on, it wants to cut out.
Turn engine off and leave for a min, start back up with no probs, same again, runs for less time this time (obviously a temp issue) and again when you
give any throttle, wants to die.
Ive emptied the tank, changed full filter, cleaned carbs and jets because of fuel sitting there and still same issue.
Never checked the colds, but could it be this?
