coil on plug

[Guest]

http://www.autotap.com/techlibrary/understanding_multi-coil_ignition_systems.asp

anybody play around with this mod at all? I ran into a guy last summer had them on his kz1000. he liked them and claimed a performance increase.

[Brendan W]

Sounds interesting. Hotter spark has to be better. I am always a bit suspicious of reported improvements after any upgrade as generally you have no idea how bad the old stuff really was in the first place. Had he coils at plugs or some CNP system. How was he picking up firing signals? One pickup as a crank sensor and some ECU or still using two pickups and a wasted spark ? Somehow I don't see getting an ECU to handle it would be a simple affair and the real advantage would be just the hotter spark but probably in a wasted set up which would seem to undermine a lot of the reasons for COP in the first place. If you could rig an ecu with , MAF, knock and temperature sensors maybe you could exploit the full potential of COP although you would probably need fuel injection as well
Just talked myself out of it haven't I.

[fastbysuzuki]

quite a lot of modern cars use this, the coil is part of the plug cap I guess one benifit is if one goes down you would not have to by a complete coil pack on a car, as for our GS's if one went down it would only take one cylinder out as opposed to the standard setup where two cylinders go down.

[tkent02]

I'm thinking a set from a wrecking yard six cylinder car would give you four to use plus a couple spares. Can you just trigger them from the bike's normal ignition or is there more to it? Does it have to be computerized?

[barnbiketom]

Watch out, most are .5 ohms an will draw way too much current.you will have charging problems an possibly damage the ignitor.
There are some that are 1 ohm..i forget which ones but if you arrrange them in series... that is cylinders1/4..and 2/3 i think it would work

[tkent02]

Something that could be fixed with a big resistor?

[Weapon]

the ones I am considering are from a 03 and up honda 600 rr. if you want to look at the stats. and yes its using the existing coil wires with a wasted spark. I think the coil charge times are improved though. I doubt that cops made for bikes are gonna be a heavy draw item.
good point Brendan, but even if it is an improvement over old failing equipment its still an improvement, even if its a net gain of zero. no?

[60ratrod]

I think it would be possible with the existing ignition system. the only thing that I would see needing change with a COP or CNP system is splitting the signal wire coming from the ignitor to the respective cylinders, since you already have the signal generator running the ignitor. but this would still be a wasted spark system unless you managed an ecm of some sort. and if you are going to run an ecm, you may as well go a head and look into going into some sort of efi, be it either a TBI, MPFI, CPEFI system. I think those running the dyna 2000 systems could do it relatively easy since the 2000 kits already have a "brain" box

[posplayr]

I was hoping by now someone would have shown a picture for a COP for a motorcycle? Were you making a special mounting bracket to support the coil? Also not sure what the advantage is unless you're talking about low ohm coils. For a V-8 or V-6 getting rid of the distributor with cap, rotor and all those secondary ignition wires is a real benefit. Most COPs I have seen have a short secondary wire coming out of them to go over the plug and the coil is bolted to the valve cover. If the coil driver is not inside of the COP , then in theory the ignitor could drive the COP just like a normal coil (although you now need 4 coils??). So the trade is 2 coils(frame mounted) with four extended wires none of which is over 1 foot long or 4 coils(valve cover mounted) with 3" long plugs wires?

It would seem the only real benefit is if you can get a cheap high performance coil that is COP off of a car but then you would need a Dyna 2000 or something else that could drive a low impedance coil.

[Weapon]

apparently the ticket is to run them in series to double the resistance to within acceptable levels. because most of them are 1.5 .6 ohms and they need to be around 3 ohms. but yes connected to the coil wires and no bracket seems to be necessary. from what I remember on the kz they were a bit long but not floppy or anything. the ones for the 600rr just snap onto the plug like a plug boot. you need plugs that the cap unthreads though. this is what one of the guys on oldskoolsuzuki did on his gixxer.

picture courtesy of buddy on oldskoolsuzuki



when I do it I will be following this example

[60ratrod]

by looking at the diagram, how do the 2 coils talk to one another?

[posplayr]

by looking at the diagram, how do the 2 coils talk to one another?

They just fire 1-4 and 2-3. Assuming it works, then the coils secondary have to be grounded so that the wasted spark current path can be completed through the ground. This is a little different as I think the OEm coils secondaries are isolated from ground.

[barnbiketom]

Something that could be fixed with a big resistor?

That will work also, but the overall point of a higher volt spark would probably suffer.
I had COPs on a old honda chopper 2 years ago to experiment and it ran fine, but burned the points in 3 days lol.
I would think bike COPs have higher primary resistance than cars..since cars have a 100 amp alternator lol and even most new bikes not nearly as much!!
On the ones I used , the secondaries grounded thru another wire in the plug, not the mounting bolt.
further, a fourth wire was used (i think) for the PCM sense? I left it unhooked