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Registered:
November 2004
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Location:
Brisbane
Registered:
February 2003
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Re: 4agze twin coil ----> individual coils over plugs
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Tue, 06 December 2005 15:23
 
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not likely, the ignitor wasn't designed to run two coils from one signal wire.
You'd probably end up with a weak spark as the dwell time provided by the ignitor is for that design of the waste-spark coil, not two coils running in parallel.
Also, the twin-point coil-packs need both towers connected to plugs to work correctly so you would need 4 new individual coil packs to attempt what you are proposing.
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Registered:
November 2004
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Location:
Brisbane
Registered:
February 2003
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Re: 4agze twin coil ----> individual coils over plugs
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Tue, 06 December 2005 15:34
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no, by splitting the output(s) from the igniter to two coils (instead of the one coilpack), each coil will get 50% of the current that the pack used to get for one spark event.
it might work - not knowing how over-designed the igniter might be - but my money is on it not working well at all.
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Registered:
November 2004
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I Supported Toymods
Location:
Nthn Beaches, Sydney
Registered:
October 2004
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Re: 4agze twin coil ----> individual coils over plugs
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Tue, 06 December 2005 23:58
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| TauhuTauhu wrote on Wed, 07 December 2005 02:38 |
does current affect the spark??
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yes
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Location:
Brisbane
Registered:
July 2005
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Re: 4agze twin coil ----> individual coils over plugs
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Wed, 07 December 2005 00:52
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Voltage = force
ie how far the spark will jump.
Current = coulombs sec-1. volume essentially.
ie how fat your spark is.
Compare skinny guy jumping the same distance as big fat guy.
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: 4agze twin coil ----> individual coils over plugs
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Wed, 07 December 2005 00:53
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You WILL need 4 igniters!
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Location:
Brisbane
Registered:
July 2005
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Re: 4agze twin coil ----> individual coils over plugs
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Wed, 07 December 2005 01:07
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chuckster,
i wana understand this "coil on spark" or waste spark set up that toyota uses coz i hadn seen it till i got my 1G.
I thought that each coil essentially fed the stepped up voltage to two spark plugs. Thus giving a simultaneous spark on two cylinders, one on compression stroke, one on exhaust stroke.
But if this is the right understanding, then i would think it wouldn matter if you split the signal before the coils. It would just be like re-arranging the order of a mathematical equation but still getting the same answer.
Each coil would only get half the current, but it would be stepping it up for half the load.
The question that springs to mind next, is how efficient is a coil in the first place? Meaning, what % of igniter signal actually gets converted to a spark and not lost to heat etc. Coz obviously having twice as many means double the loss due any slight in-efficiencies. And furthermore, how does different current levels effect the efficiency of the chosen coil.
As long as there is minimal difference in efficiency i THINK it should be fine...
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Registered:
November 2004
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Re: 4agze twin coil ----> individual coils over plugs
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Wed, 07 December 2005 03:13
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mic*,
Coil Over Plug ignition doesnt have wasted spark.
the ignition is fully sequential..
1 coil firing each time. they do not use crank anggle sensor but they use cam phase sensor instead, just like the distributor. so they know the exact location of the pistons and the engine cycle.
but in the twin coil system, crank angle sensor is used. so the ecu only knows the location of the pistons but not the cycle..
so each coil will receive 1 signal from the ignitor, then each fires 2 cylinders at once. 1 on compression stroke, 1 on exhaust stroke.
i still dun understand how it is going to affect the sprak by splitting the ignition signal wire into 2 and get them onto 1 coil each...
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Location:
Brisbane
Registered:
July 2005
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Re: 4agze twin coil ----> individual coils over plugs
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Wed, 07 December 2005 04:18
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OK so we're talkin bout two different systems here? Forget about mine - coil on spark... ?
But you have twin coil right?
Well if thats right, we both said one coil is firing two cylinders simultaneously.
A coil is jus a step up transformer.
If you use four coils that step up at the same ratio of primary to secondary windings as the original two, you would have no overall affect.
Its jus simply stepping up after the current split rather than before.
I read up. Transformers are highly efficient to the point where loss is basically irrelevant. Therefore,
Power in = power out
P = V X A
The ratio of V:A changes and splits in two, but the order that you do it in doesnt matter.
Which makes me ask why would you do this? Oh and i doubt that SR20 coils would have the same ratio of windings.
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Location:
Montrose, VIC
Registered:
May 2002
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Re: 4agze twin coil ----> individual coils over plugs
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Wed, 07 December 2005 04:46
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Is you ignition inadequate and causing problems at the moment? Are you likely to gain anything by changing it?
Having said that, JZ coils fit into a 4AG head fairly easily...
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Location:
Rocky Mountains, Canada
Registered:
May 2002
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I Supported Toymods
Location:
south Melbourne/KL
Registered:
June 2004
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Re: 4agze twin coil ----> individual coils over plugs
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Wed, 07 December 2005 05:54
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tahu tahu are u frm ZTH forum?
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Registered:
November 2004
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Re: 4agze twin coil ----> individual coils over plugs
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Wed, 07 December 2005 06:11
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yes i am. i recognise ur car. haha
u're frm there also rite? 
i'm actually using 20valves silverhead with blacktop ecu running map sensor.
not long ago, i changed my ignition system to dli type from 4agze. using VR4's coil packs
but i dont use the crank sensor to give ignition signal, i still use the signal frm the distributor to the 4agze ecu.
changing the ignition system to dli using 4agze's ecu gives some performance. then, changing the twin coil packs frm 4agze's to mitsubishi VR4's giv more performance again.
so, i think it's the coils tht is giving stronger spark?
but the different ignition map frm the 4agze ecu may olso be the factor of the power increment.
tht's y i'm thinkin abt using individual coils now.
coz if i sell my current coil packs and plug cables, i can get 4 individual coils. it's worth to have a change rite if it gives more power?
so which 1 will likely be the problem to the individual coils setup?
burnt ignitor?
weaker spark?
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I Supported Toymods
Location:
south Melbourne/KL
Registered:
June 2004
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Re: 4agze twin coil ----> individual coils over plugs
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Wed, 07 December 2005 06:47
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im goin kl on 12th dec. need any luggage size parts from melbourne?
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Location:
Brisbane
Registered:
July 2005
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Re: 4agze twin coil ----> individual coils over plugs
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Wed, 07 December 2005 08:15
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If its gonna blow your igniter id like to know why? If plug resistance does not change, how will the igniter get over amped and blow?
The coil you use will just trade off amps for volts one way or another. Power of the spark is the same.
Im not sure exactly whats best for causing ignition. Perhaps once you have the volts to jump your gap, increasing voltage further (reducing amps) is gonna get deminished results.
Whats gonna make a better fire? Throwing a few electrons accross a fixed gap really hard, or throw more electrons over the same gap not so hard.
Anyone ever got that far???
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Location:
Brisbane
Registered:
February 2003
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Re: 4agze twin coil ----> individual coils over plugs
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Wed, 07 December 2005 12:55
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| mic* wrote on Wed, 07 December 2005 11:07 |
i wana understand this "coil on spark" or waste spark set up that toyota uses coz i hadn seen it till i got my 1G.
I thought that each coil essentially fed the stepped up voltage to two spark plugs. Thus giving a simultaneous spark on two cylinders, one on compression stroke, one on exhaust stroke.
Each coil would only get half the current, but it would be stepping it up for half the load.
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yup, the 1ggze uses waste-spark - different from coil-on-plug or individual coils for each plug.
When a waste-spark fires, the spark plug in a fuel-laden atmosphere will produce a significant spark (e.g. 10s of thousands of volts) and at the same time, the 2nd plus will be in a post-combustion atmosphere and will produce a weak spark of several hundred volts.
The sparks have different characteristics (current/voltage requirements) so they're not just two same-sized sparks from the one coil.
Each igniter (sorry for dodgy spelling earlier) only drives the low-voltage side of one coil, driving two coils will pull too much current thru the device and it will pop/fail.
If you want Coil-on-plug (for a 4cyl), then you should get an aftermarket ECU that has at least 4 ingiter channels.
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Registered:
November 2004
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Re: 4agze twin coil ----> individual coils over plugs
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Wed, 07 December 2005 13:12
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| Quote: |
Each igniter (sorry for dodgy spelling earlier) only drives the low-voltage side of one coil, driving two coils will pull too much current thru the device and it will pop/fail.
If you want Coil-on-plug (for a 4cyl), then you should get an aftermarket ECU that has at least 4 ingiter channels.
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does that mean an oem 4agze has 2 ignitors signalling the 2 coils?
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im goin kl on 12th dec. need any luggage size parts from melbourne?
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too bad, i'm in Sarawak
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Location:
Brisbane
Registered:
February 2003
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Re: 4agze twin coil ----> individual coils over plugs
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Wed, 07 December 2005 13:37
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| TauhuTauhu wrote on Wed, 07 December 2005 23:12 |
| Quote: |
Each igniter (sorry for dodgy spelling earlier) only drives the low-voltage side of one coil, driving two coils will pull too much current thru the device and it will pop/fail.
If you want Coil-on-plug (for a 4cyl), then you should get an aftermarket ECU that has at least 4 ingiter channels.
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does that mean an oem 4agze has 2 ignitors signalling the 2 coils?
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yes.
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Location:
Brisbane
Registered:
July 2005
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Re: 4agze twin coil ----> individual coils over plugs
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Wed, 07 December 2005 22:54
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chuckster,
So what i am understanding is basically the electrical properties of the two signals will be the same. But in a fuel/air mixed environment, the conductivity of this gaseous state is much greater than in an exhaust gas environment, thus lower resistance, and exponetially more current flows through the plug in the air fuel mix than the plug in the exhaust mix.
Is that right?
I understand that the igniter supplies a signal to the low voltage windings of any coil.
V = I x R
A transformer or coil has negligable resistance, it does exactly what the name suggests, transforms the releationship of current to voltage.
The resistance in the circuit determines current draw. In our case this is the spark plug.
If we split the signal from the igniter then transform it in two coils, the coil delivering to the exhaust stroke plug would still have much too high a resistance (the same as it always was) to draw much current.
Basically im sayin that the plug resistance determines current draw as far as my understanding goes, and if it doesnt change, then current draw wouldnt either.
Can you point if there is anything wrong with the above, and also, how does "coil on spark" differ?
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Location:
Rosanna, Melb
Registered:
June 2002
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Re: 4agze twin coil ----> individual coils over plugs
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Thu, 08 December 2005 03:01
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Mic, I don't think it is that simple.
An igniter controls the coil. It lets current run through the low voltage side of the coil, setting up a magnetic field through the entire coil. It then stops the current flow and so the magnetic field collapses, causing a brief, huge voltage spike to be produced in the high voltage side of the coil. This spike is what makes the spark plugs spark.
I think what the guys above have been trying to say is that a 4AGZE igniter can easily run one coil. That is, it can safely flow enough current to run one coil well. If you split it and run two coils off the one igniter, then it will need to flow twice as much current to saturate both coils. And this extra current will cause the problems.
Hen
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Registered:
November 2004
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Re: 4agze twin coil ----> individual coils over plugs
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Thu, 08 December 2005 04:40
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y is tht the spark on the exhaust stroke is weaker?
the waste spark ignition system cant possibly do tht because the ecu doesnt kknow which cylinder is running the intake/exhaust stroke.
the ecu gets the signal frm the crank angle sensor, knowing only the position of the pistons, not the engine cycle. ie: which 2 pistons are reaching the TDC, but not which piston is on the compression stroke and which is on the exhaust stroke. so 1 of 2 coils will spark both the cylinders with the same spark.
mic, do u mean coil on plug system?
if u're asking abt tht, it's different with waste spark system.
for COP, there will be a cam phase sensor which can tell the ecu the location of the pistons and the cycle of the engine.
let's say pistons 1 and 4 r reaching the TDC, the cam phase sensor is able to determine which of them is on compression and which of them is on exhaust stroke.
so, the ecu will only send signal to the coil working on the compression stroke.
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Location:
Brisbane
Registered:
February 2003
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Re: 4agze twin coil ----> individual coils over plugs
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Thu, 08 December 2005 05:36
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| TauhuTauhu wrote on Thu, 08 December 2005 14:40 |
y is tht the spark on the exhaust stroke is weaker?
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A spark event will occur post-combustion - a weak one yes, but a spark none the less. From memory, that spark is in the hundreds-of-volts range.
the reason it's weak is the atmosphere in the cylinder head. Combustion gasses are not condusive to sustaining a high-voltage arc.
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... so 1 of 2 coils will spark both the cylinders with the same spark.
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yes, but one cyl gets a much weaker than the other (see above).
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Location:
Brisbane
Registered:
July 2005
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Re: 4agze twin coil ----> individual coils over plugs
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Thu, 08 December 2005 07:42
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ok. Forget about coil on spark. I have caused this confusion coz i am not familliar with waste spark, but have had a waste spark system - mine - being called coil on spark to me by ppl who should know better.
I agree with chuck. Conductivity in different gaseous environments will causes different sparks.
Should they be free air, they would produce the same spark simultaneously.
Henn,
I appreciate your logic, but i feel that your understanding of how transformers / coils work is a little bit different to mine.
My understanding is transformers or coils dont consume power they transform it hence the name. This is done by two sets of coils. The primary coil (from igniter) creates an electromagnetic field which induces a current into the secondary coil (to the plug). The ratio of primary to secondary windings = the Vin to Vout ratio;
Power in = Power out
P = V x I therefore, letting the = sign be the transformer
V x I = V x I
hypothetically (made up figures), you might transform;
12V @ 10amps =(into)= 12,000V @ 0.01amps
But the point is current draw is determined by the components in the circuit which have resistance. The vlotage supplied by the igniter is set, but how many amps get sucked is set by the resistance. And as far as i can see, with either one or two coils coming from an igniter, the resistance still = one plug in a compressed air/fuel mix, and one plug in a atmospheric exhaust gas mix.
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Location:
Rocky Mountains, Canada
Registered:
May 2002
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Location:
Brisbane
Registered:
July 2005
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Re: 4agze twin coil ----> individual coils over plugs
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Fri, 09 December 2005 02:04
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MWP,
Thanx. Thats what i said at the start. Its about the efficiency of the coils. And i didn think they were inefficient, you're saying they are.
Ive found out that its not really about the efficiency of the coil at all. Its the fact that the coil is being made to work differently to a typical transformer. Henn pretty well said most of it...
A coil does NOT consume power, it transforms AC power. If you pass DC through the primary windings all you have is an electromagnet which sucks power & makes heat coz it essentially a short circuit. No current will be induced in the secondary windings. Its a change in a magnetic field that induces a current - DC fields do not change. The igniter creates a changing field by passing DC current through the coil for a set time (dwell time) to build up a field before the ECU opens the circuit. The field change is only a change back to zero, but its enough to produce a spark when the coil ratio steps the voltage up to thousands of volts.
Its the dwell time that sucks the power, and if you dwell two coils in paralell off one igniter, you will double the current draw and blow the igniter. I stand corrected/educated.
However, the resistance of a coil is nearly zero ohms, so if you wired two in series, you will have next to no effect on the operating amps of the igniter circuit when it dwells. Can anyone see a reason why this wouldd not work?
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Location:
Rocky Mountains, Canada
Registered:
May 2002
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Re: 4agze twin coil ----> individual coils over plugs
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Fri, 09 December 2005 23:19
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| mic* wrote on Fri, 09 December 2005 12:34 |
However, the resistance of a coil is nearly zero ohms, so if you wired two in series, you will have next to no effect on the operating amps of the igniter circuit when it dwells. Can anyone see a reason why this wouldd not work?
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But series means each then gets 1/2 of the power = no improvment.
The answer is to simply run a second ignitor.
Running a second coil will only improve your spark if its not having time to charge at high RPMs.
At all other RPMs, running a second coil will have no effect.
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