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Re: Coil Packs and Dwell Time


belize1334
well bread and nobly conceived
1334/2000


Galant VR-4 org Post #: 922698 posted 08/14/10 12:22 PM     Remind Me!  Send Private Message   Edit Post      
Are you saying that the MAS plug actually fits with the 7-pin '91 igniter or just that it's a source for a male/female pair that can be used to build a harness?

I'll have some free time tomorrow so I can see what kind of current draw we get on the signal side of the igniter. Then maybe I can get some word from the ECU buffs about what that side can support.



Roger B. Scott
'91 Belize Green

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toybreaker Galant VR4.org Moderator
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Galant VR-4 org Post #: 922716 posted 08/14/10 01:48 PM     Remind Me!  Send Private Message   Edit Post      
Quoting Prove It:



Has anyone figured out Toybreaker concerns about frying the ECU from increased loads?








We've already exceeded my meager understanding of things quite a few posts ago.

It is important to note the ecu doesn't "see" the coil load, it only "sees" one leg of the transistor in the ignitor module.

It's that transistor that is controlling the coil action. The coil current is switched and carried by that transistor in the ignitor case. That loading goes out to ground on the large black wire from terminal #3 of the ignitor.

We are potentially doubling the switching load at the ecu by doubling up the ignitors, but it may very well turn out to be a non issue. ( I just like to cover all the bases )




Another subject I know very little about is the dynamics of what occures when we charge the coils.

Inductive reactance, counter electro motive force and all those other big words Curtis would mis-spell have to enter into this equation somewhere.

The very act of trying to charge a coil creates some interesting anomolies.

As the coil voltage rises, a magnetic field begins to form.

that's our goal, a strong, stable, consitent field

But, as the field strength increases, it will begin to resist the incoming current.

How much "resistance" (for lack of the proper term) is felt by the charging device will vary on a million little details, but there's no way around the physics of the effect.

The effect of this is seen by watching the current draw and magnetic field during the coil charging cycle.

When the circuit is first turned on, large amounts of current begin to flow, as there's no field to work against. (the only thing resisting the flow of current is the raw resistance of the inductor (wire)

As the field begins to build, the current flow begines to taper off.
the very magnetic field we are trying to create begins to resist the additional current
The resistance of the circuit is now a mix of straight resistance in the inductor, and an ever increasing amount of inductive reactance.

As the field strength grows, the anount of resistance in the wire becomes trivial, and it's the inductive reactance side of things that will take over as the determining factor in the time/current equation.

This means that just measuring the resistance of a coil only tells a very small part of the story...

We could be talking about ten turns of fine wire, a hundred turns of medium size wire, or ahtousand turns of larger wire ...

The "resistance" would read the same on a meter ... but boy howdy ... will they have a different resistance to charge!

.... and different charge times to field saturation ...

That's the whole key to this operation.

Finding a coil with the right turns ratio to make a decent spark on the secondary side, without melting things down or failing to reach full saturation on the primary side.

The guy that figures that out will be able to make a bulletproof system.




caveat I know jack shit about the laboratory side of this stuff, I just have a little hands on from back in the day.

Swapping out points for an hei systems was a common mod back in the day.

Kenn Inn is probably the only other guy on this board that knows how sweet those days were.

I was hanging "late model" (80's ) Bosch guts into old school porsche distributors, fabbing up the harnesses, and making good money doing it.

Took a few false starts, and I burned up a few ignitors and coils along the way, I did ... , but the end results were worth it!

I hope you guys can achieve the same success!

(minus the burning shit up stage of the r & d proccess )


Edited by toybreaker (08/15/10 12:49 PM)

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toybreaker Galant VR4.org Moderator
it's peace of mind at 100 mph plus
1990/2000


Galant VR-4 org Post #: 922720 posted 08/14/10 02:08 PM     Remind Me!  Send Private Message   Edit Post      
Quoting broxma:

I am almost certain the coils are not directional. They work regardless of which wire is connected to pos/neg.

/brox




The coils may be non-directional, but the current required to fire the plug backwards from the center electrode to the ground strap is most definately orders of magnitude higher to jump from the center electrode to the ground strap.

... learned this one the hard way ...



the bitterness of low quality remains long after the temporary joy of a low price has faded

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broxma
retard monkey strength
379/1000


Galant VR-4 org Post #: 922721 posted 08/14/10 02:13 PM     Remind Me!  Send Private Message   Edit Post      
Quoting belize1334:

Are you saying that the MAS plug actually fits with the 7-pin '91 igniter or just that it's a source for a male/female pair that can be used to build a harness?




I am. It is the exact same harness plug with a wire in a different position. If we could remove the pin and relocate it, everything would hook right up.

I have run into a problem with my car not at all related to the ignition system. Basically I had a bad break in due to not enough hone on the cylinders during the rebuild. I am in the process of remedying this now but in the meantime...

I pulled the plugs out the other day when I was diagnosing my lack of compression and found I had been running spark gaps in the range of 27 or so. I know that factory spec has a value listed around this however this is way to high for a high boost application. At spark gaps from 27-30 or so, the car still has intermittent skip of the ignition firing. The general response to this is drop the gap to reduce the resistance between the poles on the plug. Over at EvoM, there have been many discussions about spark gap using different ignitions and I had generally settled on a gap of about 22 for my Evo which runs like a clock at 25+ PSI. Consequently, I dropped the gap down to 22 and magically all issues are gone. Once I have the rebuild done, I will do some testing with in car video for different levels at a steady PSI.

I am also going to do some power tests to the dual ignitor system to see what type of output I am getting from the ignitors to the coils.

/brox



I am big into recycling though and if your not into sacrifice or burnt offerings, you may want to stick with 93 octane.

/brox

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broxma
retard monkey strength
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Galant VR-4 org Post #: 922742 posted 08/14/10 04:40 PM     Remind Me!  Send Private Message   Edit Post      
Under what guideline could we assume a coil to be better than another? Would a simple check for resistance across the main plug pins be able to categorically say one coil has more winding, more resistance and should perform better? Is a higher resistance in this case better?

The Chrysler coils show about .7 by my RMS meter. I found a coil off a Camry today which relative in size is much larger than the Chrysler coils, has essentially the same mounting profile and measures 1.4 across the pins. I assume this means more coil. I assume this means better coil. I can take a picture and show you the exact coils I picked up but they came off an early 2000 Toyota V6, I believe a Camry.

/brox



I am big into recycling though and if your not into sacrifice or burnt offerings, you may want to stick with 93 octane.

/brox

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SouthCaliVR4
Gas Analyzer
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Galant VR-4 org Post #: 922746 posted 08/14/10 04:57 PM     Remind Me!  Send Private Message   Edit Post      
If so that would rock, I have a set of toyota v6 coils sitting on my box. I was debating building a plate & giving them a try.



How do you make a small fortune racing? Start with a very large one!!!

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Justin
Unregistered


Galant VR-4 org Post #: 922822 posted 08/15/10 03:33 AM     Remind Me!  Send Private Message   Edit Post      
I don't know if it means anything, but I sold parts for about 3 years. The parts store I worked at moved over $35k in parts PER DAY. I sold hundreds of F-150 5.4 coils, a few chrysler coils, but I never sold a toyota COP coil. Ever. That tells me that they don't fail. I think it would be worth a try.

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broxma
retard monkey strength
379/1000


Galant VR-4 org Post #: 922825 posted 08/15/10 04:11 AM     Remind Me!  Send Private Message   Edit Post      
The funny thing about the Toyota coils is the top is just a clear silicone plug material. You can see the coil through it.

/brox



I am big into recycling though and if your not into sacrifice or burnt offerings, you may want to stick with 93 octane.

/brox

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curtis Galant VR4.org Moderator
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Galant VR-4 org Post #: 922924 posted 08/15/10 10:16 PM     Remind Me!  Send Private Message   Edit Post      
Well ford coils are junk shit for sure don't even think about those or those damn pencil bike coils some use. Alot you see for sale used on ebay are there because there shit and have broken down internally and been replaced under recall from the bike dealers. I have a set of mitsubishi coils from a Grand Vitara. Yea I know but there mitsubishi coils. But the windings are smaller on those sexy little units but just don't have the punch I would bet. As for non directional and directional the 300m intrepid coils can be charged in either direction.

Here's the napkin drawing that I've used for 30 plus plates I've built that we/me came up with years ago when I did the thread on all of this. You can feed 1 then 4 or 4 then 1 or the same with 2 and 3 but wired up any other way want run. I showed this to some of my professors at school and they couldn't figure out what was going on and said it shouldn't run but it being a wasted spark makes it work I guess. If the 1 and 4 are tied straight together I think its the charge time that keeps it from going but back when I did this I think I wired them up with every possible way and this was the only way they would run. My buddy tried his evo and we never got it to work and then after he bought a CDi box would dedicate a day to waste on getting it going. Now with a cdi box I'm sure each coil could be ran from its own circuit and would be fine. I have 2 old school HKS boxes here for when the car goes back together but haven't found any instructions on how to wire them up.




As for what you guys are doing bravo, I'm not a spark chasing type but I really think the whole twin transistor steps will work if paired up correctly with the correct wiring and heat sinks. As for that try a computer repair shop I'm sure they have some large heat sinks with big fans laying around for cheap. Most computer fans are 12 volt dc as well so your set and the fancy heat sink greases are any where from 3 to 9 bucks at radio shack for a microscopic tube. There's different grades. I bought the cheaper white stuff for my plasma cutter this spring during its rebuild because thats what was there already.


Another thing to do is mod the springs in the boots to lower the resistivity of the transfer of current. I always cut the boots down in lenght then solder a piece of copper braid into the spring. The resistivity drops to nothing point nothing.


If you guys need any help with this yell and I'll try to be of assistance. Have a mill and may have some heat sink ideas for you.



92 GVR4 0475/1000
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belize1334
well bread and nobly conceived
1334/2000


Galant VR-4 org Post #: 923041 posted 08/16/10 01:25 PM     Remind Me!  Send Private Message   Edit Post      
In order to qualify directly whether a coil is "better" than the OEM coil, you need for it to satisfy two conditions. It needs to store more energy at full charge and it needs to achieve full charge as fast or faster than the OEM coils in order to respond in the time allowed. Now, the current achieved over infinite charge time is just I=V/R. And the energy stored by that current is E=(1/2)L I^2 = (1/2) L (V/R) ^2 = (1/2) V ^2 * (L / R^2)... that is, the energy rises with L but falls off with R^2. Now, to ensure that the charge time be similar to the OEM coils, we have to define T = L/R. That is the characteristic time for a RL circuit to rise to 70% of it's max possible current. So, keeping R/L roughly the same as stock, I can explore what happens of their either BOTH bigger than stock or BOTH smaller. Rewrite the energy to keep T = L/R fixed and we have, E = (1/2) V^2 T/R. That is, keeping T fixed the energy still depends on 1/R. So, if you want to store MORE energy and keep the same charging time, you should DECREASE the resistance AND the inductance while keeping the ratio of R/L approximately fixed.

SO, the stock coils have R=0.8 Ohm and L=3.9mH which puts T=5ms. If you want to replace them with BETTER coils then you'll want to look for coils which have BOTH R and L smaller than these values while maintaining T = L/R ~ 5 ms. The intrepid coils, unfortunately, do not do this. They come in at R=0.8Ohm and L=2.9mH when wired in series. That makes the value of T slightly shorter (which is ok) but also lowers the stored energy (which is less awesome). Hense the doubling of the igniters which should lower the system resistance and bring T back into line as well as raising the stored energy.

And remember, resistance and inductance BOTH add normally in series and reciprocally when in parallel. So, if you're looking at a set of four coils you have to figure out whether to put them in series or parallel in order to get them to duplicate the values of the two OEM coils.



As for the question of the spark going the wrong way over the plug. Unless you're dealing with an inherently directional material, such as a diode or a pnp junction, all of electricity, including currents, fields, potentials, plasma currents, etc, is invariant under interchange of sign. There is NO reason to expect that it should be harder to ionize the spark gap from the ground strap to the electrode than from the electrode to the ground strap.

To see that this MUST be the case, inspect the diagram for the OEM coils. Each coil only has ONE secondary coil and it connects to both spark plugs (one on each end). When it discharges the current flows down through on plug and up through the other to complete the path. The plugs themselves couldn't care less which direction the charge is flowing. In fact, I suspect that the discharge current is actually A/C and not D/C given that the oscillating field necessary to induce the breakdown voltage would have to be EXTREMELY FAST in order to build up to the necessary strength. That means that in the time it takes to discharge the spark the current over a single plug is likely switching direction over and over, making polarity an inapplicable concept.

If you say that you had issues with wiring one of the coils backwards then I SUSPECT that it was a wiring problem. Notice that the Intrepid coils on have three available terminals. For simplicity lets call them T1, T2 and SP. Normally you hook power to T1, ground to T2, and the spark plug to SP. When the secondary fires T2 is disconnected so the current must be across T1 and SP. That means that T2->SP must be an impossible path or else we'd have had a short over T1/T2 during the charge cycle. Now, if you wire the coil backwards then it charges fine (in reverse) but the discharge goes wrong. That's because you're switching T1 to open at the point of discharge. But SP is attempting to pull current from T1 which is not connected to anything and thus kills the discharge event.

For my proposed variation to the wiring, the above problem is solved by hooking T1 from two different coils together. The first coil in the series charges backwards and the second coil charges normally. Then, at discharge, the T2 of coil two is not an open channel since it goes to the igniter ground which is open at this point. And the T2 from coil 1 is also not in the current loop since there is no SP -> T2 connection in the coils. The first coil tries to push from SP to T1 and the second coil pulls from T1 to SP. It's like a snake eating it's own tail and it makes a local current loop, feeding down over the first plug, through the head, up the second plug, through coil 2, across the connected T1 ports, and down coil 1 into the first plug again...

Now this is all speculation and I haven't wired it up yet. When I do, I suspect that I won't notice any difference. The proof, if there is any, will be that it works just as well as the other way and the benefit will be unnoticeable. But it will, in principle, reduce the current demand of the ignition circuit just a little and that'll please my sensibility.



Roger B. Scott
'91 Belize Green

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broxma
retard monkey strength
379/1000


Galant VR-4 org Post #: 923195 posted 08/17/10 12:26 AM     Remind Me!  Send Private Message   Edit Post      
How did you determine L? In simple terms please. My Electronics Principles class was 15 years ago.

This post seems to have disappeared or at least got lost. I am posting so I can find it again.

And I'll be testing the Toyota coils shortly.

Edit - NM. Sticky. Got it.

/brox



I am big into recycling though and if your not into sacrifice or burnt offerings, you may want to stick with 93 octane.

/brox


Edited by broxma (08/17/10 12:31 AM)

Posts: 911 | From: San Antonio Tx | Member Since: 11/16/09 | IP: (99.52.72.193) | Report this post to a Moderator

belize1334
well bread and nobly conceived
1334/2000


Galant VR-4 org Post #: 923305 posted 08/17/10 12:05 PM     Remind Me!  Send Private Message   Edit Post      
To get L you need either an impedance (z) meter or else an oscilloscope. A standard multimeter can't get it for you. The z-meter works much the way an oscilloscope would by measuring the time-constant and comparing against a peak current value. First it applies a voltage and measures the current as it ramps up. After about a second the current has achieved 99.9999999% of the ultimate current value and that is used to determine the total resistance of the system. Then you measure the time it takes to reach ~70% of that value. That time is T=L/R. You already know R from step one so you just plug it in and solve for L.

There's another, more complicated way to do it, which will be POSSIBLE with just a multimeter and a variable frequency voltage source. You have to set up an RLC circuit with know R and C. You put the multimeter across the inductor and measure AC voltage. Then you tune the voltage source frequency until the voltage over the inductor is maxed out. That frequency corresponds to the resonant frequency and is given by 1/SQRT(LC). But again, you need at least one expensive piece of equipment... the AC power supply.

If you have access to or know somebody in a Physics or Electrical Engineering program at a college or university then it's a simple thing to measure the value and they'll know what equipment to use and what it all means.



Roger B. Scott
'91 Belize Green

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broxma
retard monkey strength
379/1000


Galant VR-4 org Post #: 923382 posted 08/17/10 03:59 PM     Remind Me!  Send Private Message   Edit Post      
Would you happen to be someone with access to physics or electronic test equipment who could test such things? I can mail you a coil so we can find out. I'll send all 4 if you want to do some comparison testing or something. I can get more for nothing so it's not a thing.

/brox



I am big into recycling though and if your not into sacrifice or burnt offerings, you may want to stick with 93 octane.

/brox

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prove_it
my racist jokes aren't actually funny
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Galant VR-4 org Post #: 923717 posted 08/18/10 12:44 PM     Remind Me!  Send Private Message   Edit Post      
Quick question, on your guys chrysler coils, whats the length of the spring between the coil and plug? Or does it matter?



#1284/2K NB, Totaled
#715/1K KG, Rebuilding
02 Acura TL daily duty unit

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broxma
retard monkey strength
379/1000


Galant VR-4 org Post #: 923760 posted 08/18/10 03:40 PM     Remind Me!  Send Private Message   Edit Post      
It does. Once you cut the boot to sit on the plug, the spring is then too long and will prevent you from putting it on fully. I chopped a bit off both ends until I ended up with a good length I liked. I did this off the car with just a plug and the coil pack. Alternatively, if you cut it too short, you can deform the spring and open it up a bit to make contact. More bizarre is the contact in the bottom of the coil, is just a screw, and is often rusty.

/brox



I am big into recycling though and if your not into sacrifice or burnt offerings, you may want to stick with 93 octane.

/brox

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belize1334
well bread and nobly conceived
1334/2000


Galant VR-4 org Post #: 923766 posted 08/18/10 03:57 PM     Remind Me!  Send Private Message   Edit Post      
Yes, if somebody sent me a coil I could test the inductance of the primary. I did this on my OEM and Intrepid coils and that's how I got the numbers I posted earlier in the thread. For some reason I wasn't able to test the inductance of the secondary... not sure why.

The spring length only matters to the extent that it makes a good connection. It's not tightly wound enough to affect the inductance of the system and it's not got enough resistance to affect the overall impedance. For our purposes it's just a wire.



Roger B. Scott
'91 Belize Green

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belize1334
well bread and nobly conceived
1334/2000


Galant VR-4 org Post #: 932353 posted 09/17/10 09:51 PM     Remind Me!  Send Private Message   Edit Post      
This is a brief update to describe the expansion harness which I just built. I haven't installed it yet so no test report... just a description of the construction.

I began with an extra j722t igniter with associated harness and a j22 igniter, also with associated harness. Now recall, the idea is to splice into the existing system so that two igniters can be run in parallel with common shared terminals. I'm using a j22 ('90) in parallel with a j722t ('91+) simply because it doesn't have the tacho module which makes it in some ways simpler. You could easily just use two j722t igniters and leave the tacho from one of them disconnected.

1) I began by cracking open the j722t igniter. This is going to be the first piece of the plug-n-play harness and will plug into the factory harness and provide pin-outs that I can use to attach the rest of the harness. As you can see in the first image I used my dremel to bore away some of the plastic so that I could get a screw-driver under the metal backing plate. I then pried up the backing plate and pulled it out. The circuit board is glued to this plate and has leads which are soldered to the pins so you'll want to carefully sort of twist it away, ripping the soldered leads off, but preserving the pins which will be your solder points. I then beat on the circuit board a bit with a hammer until it was cracked enough that I could easily chip it off of the backing plate which I'll be reusing. I also enlarged the hole made by the dremel so that there'd be room to pass the new wires through the back (there will be 12 of them). Note the image was taken after I was done soldering but it demonstrates how I made my grinds. Also, be prepared to get some goop on your hands. The igniter is packed with some kind of gel to protect against moisture (I presume) and you're gonna get it on you...



2) I began comparing the diagrams of the two systems and then checking the pin numbers against wire color. BEHOLD... both igniter harnesses use the EXACT same color scheme for the wires. The '90 harness is missing the white and white/black wires for the tacho but otherwise it matches up across the board. That means you don't have to know what the wires do... just pair up according to color. For reference, the '91+ colors are ordered yb yr b w bw y yg from 1-8 respectively. If you look at the above diagram you can figure out the functions and note that the '90 harness has a different order but uses the same color - function mapping. I routed both sets of wires through a common loom, twisted pairs together and then clipped them to the appropriate lengths. You'll have to decide how best to do this.

3) I then had an idea to make things easy on myself. Noting that I was just extending the harness at this point, I took another spare '91+ harness and plugged it into my now gutted igniter. Then I just soldered the wires so that the colors lined up straight across from the same colors on the spare harness. You could also remember the color order and make a diagram or whatever suits your fancy... this just made it easier for me since it simulates the arrangement once it's all installed.



Soldering this was a bit of a pain but if you're careful it shouldn't be an issue. I then went through and tested continuity as well as wiggling the wires around to make sure nothing would come loose. Here's another picture of the (almost) final product. I still have to glue the backing plate on and then install it. It should plug directly into the loom via the gutted igniter and then support the installation of two more igniters (a '90 and a '91+) which will operate in parallel as we've discussed.



A few final notes. If I were to do it again I'd just use two '91 igniters and leave the tacho of one disconnected. This would make the wiring a little more intuitive and also mean that both igniters were identical so if either burnt out I could replace with the same replacement part. Regardless, I expect this to work fine... barring my having f'ed something up. I'll update after I've installed it and have something to report.

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solidviper89
Patty Purex
0425/2000


Galant VR-4 org Post #: 933125 posted 09/20/10 10:11 PM     Remind Me!  Send Private Message   Edit Post      
Quoting broxma:

Quoting belize1334:

Are you saying that the MAS plug actually fits with the 7-pin '91 igniter or just that it's a source for a male/female pair that can be used to build a harness?




I am. It is the exact same harness plug with a wire in a different position. If we could remove the pin and relocate it, everything would hook right up.

I have run into a problem with my car not at all related to the ignition system. Basically I had a bad break in due to not enough hone on the cylinders during the rebuild. I am in the process of remedying this now but in the meantime...

I pulled the plugs out the other day when I was diagnosing my lack of compression and found I had been running spark gaps in the range of 27 or so. I know that factory spec has a value listed around this however this is way to high for a high boost application. At spark gaps from 27-30 or so, the car still has intermittent skip of the ignition firing. The general response to this is drop the gap to reduce the resistance between the poles on the plug. Over at EvoM, there have been many discussions about spark gap using different ignitions and I had generally settled on a gap of about 22 for my Evo which runs like a clock at 25+ PSI. Consequently, I dropped the gap down to 22 and magically all issues are gone. Once I have the rebuild done, I will do some testing with in car video for different levels at a steady PSI.

I am also going to do some power tests to the dual ignitor system to see what type of output I am getting from the ignitors to the coils.

/brox




I agree with this, I got my 2g mas harness from the 1g igniter harness.



Motivational Poster poster.

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prove_it
my racist jokes aren't actually funny
715/1000
1284/2000


Galant VR-4 org Post #: 1005668 posted 07/15/11 09:00 PM     Remind Me!  Send Private Message   Edit Post      
Bringing this thread back to life,

I was wondering if anyone has been running the dual igniter setup for a while now and could chime in about durability of this project.

Any input would be great



#1284/2K NB, Totaled
#715/1K KG, Rebuilding
02 Acura TL daily duty unit

12yr+ Vr4 owner.
Honda/Acura master tech.
Family Guy

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belize1334
well bread and nobly conceived
1334/2000


Galant VR-4 org Post #: 1006145 posted 07/18/11 12:04 PM     Remind Me!  Send Private Message   Edit Post      
I ran mine for about a week with the dual igniter and had no issues. Unfortunately, I wasn't on a big enough turbo to really test the limits either way so I went back to a single igniter which was sufficient for my needs. I've since gone back to a stock coil since I was able to find a JDM bracket to work with my cyclone manifold. Ultimately, I think that any issues would have to be a result of overtaxing the stock ignition circuit. If someone were to wire a dual igniter setup to draw from a dedicated power line I image that it would be very robust.

On a related note, I did eventually test my alternate coil wiring idea (i.e. charge first coil in reverse). It worked beautifully. The engine ran every bit as strong as the more common wiring with the slight advantage that my ignition key didn't seem to warm up as much after a long drive. I attribute this to the fact that with the first coil wired backwards the subsequent spark results in a closed circuit between the two coils and the head, as opposed to two parallel circuits both drawing power through the main ignition circuit. In addition, I predict a more even spark since the secondary of the second coil no longer draws power through the primary of the first coil when discharging. In pracitce however my setup just isn't extreme enough to test the limits of either design so I can only say that it seems to be "as good" as the more common method. That COP setup has now been sold since I went back to the stock coils... cash rules everything around me.



Roger B. Scott
'91 Belize Green

Posts: 3295 | From: Dundee, Scotland, UK | Member Since: 11/18/03 | IP: (153.90.194.143) | Report this post to a Moderator

prove_it
my racist jokes aren't actually funny
715/1000
1284/2000


Galant VR-4 org Post #: 1006161 posted 07/18/11 01:38 PM     Remind Me!  Send Private Message   Edit Post      
I think cash rules more than just you, I think it rules us all. Do you believe that it is better to run the first coil reveresed then?



#1284/2K NB, Totaled
#715/1K KG, Rebuilding
02 Acura TL daily duty unit

12yr+ Vr4 owner.
Honda/Acura master tech.
Family Guy

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belize1334
well bread and nobly conceived
1334/2000


Galant VR-4 org Post #: 1006188 posted 07/18/11 04:41 PM     Remind Me!  Send Private Message   Edit Post      
I do but I can't prove it from an experience perspective.



Roger B. Scott
'91 Belize Green

Posts: 3295 | From: Dundee, Scotland, UK | Member Since: 11/18/03 | IP: (153.90.194.143) | Report this post to a Moderator

broxma
retard monkey strength
379/1000


Galant VR-4 org Post #: 1006707 posted 07/21/11 09:10 AM     Remind Me!  Send Private Message   Edit Post      
My car has been running on the dual ignitor setup for some time now. I like Belize am switching to a different ignition but this is not due to lack of performance out of the current setup. I did not crack open the ignitors as shown, rather I simply connected the two together from the plug wires. I have both ignitors mounted to the back of the intake manifold and I have not had any ignition skips or problems what so ever.

I am switching out to a setup which uses higher voltage coils.

/brox



I am big into recycling though and if your not into sacrifice or burnt offerings, you may want to stick with 93 octane.

/brox

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TrevorS
Junior Member


Galant VR-4 org Post #: 1077868 posted 07/26/12 08:40 PM     Remind Me!  Send Private Message   Edit Post      
Just want to say thanks to Roger and Brox for the thought and effort they put into this. It's a shame that nobody else appears to have pursued it, but personally, I'm very interested (just found this thread today).

I own a 1990 Eclipse GSX on which I've been making modest mods for about four years now. A fellow on a forum I follow recently built an Intrepid based COP on his '91 and tells me he has no misfires at all and that it runs super smooth with improved throttle response. I'm a fan of smooth and response and just today decided to take the plunge. However, in my efforts to learn as much as I could about the change, I concluded the Intrepid coils were performing to at least some degree less energetically than OE, and so, I'd started pondering changing the drive and perhaps going sequential. This thread has helped tremendously !

My plan now is to use Roger's alternative coil wiring (+12V to neg, plus to plus, neg to switch) and instead of replacing the power transistor pack with discrete components, go dual. I'll also be looking at possible use of a power relay for the coils and beefed up grounding. Congratulations on the one and only thread I've stumbled across that truly addresses this subject !


Edited by TrevorS (07/28/12 01:01 PM)

Posts: 49 | From: Newark, DE | Member Since: 07/26/12 | IP: (108.2.182.34) | Report this post to a Moderator

TrevorS
Junior Member


Galant VR-4 org Post #: 1078699 posted 08/01/12 03:23 PM     Remind Me!  Send Private Message   Edit Post   
Quoting belize1334:


If you say that you had issues with wiring one of the coils backwards then I SUSPECT that it was a wiring problem. Notice that the Intrepid coils on have three available terminals. For simplicity lets call them T1, T2 and SP. Normally you hook power to T1, ground to T2, and the spark plug to SP. When the secondary fires T2 is disconnected so the current must be across T1 and SP. That means that T2->SP must be an impossible path or else we'd have had a short over T1/T2 during the charge cycle. Now, if you wire the coil backwards then it charges fine (in reverse) but the discharge goes wrong. That's because you're switching T1 to open at the point of discharge. But SP is attempting to pull current from T1 which is not connected to anything and thus kills the discharge event.

For my proposed variation to the wiring, the above problem is solved by hooking T1 from two different coils together. The first coil in the series charges backwards and the second coil charges normally. Then, at discharge, the T2 of coil two is not an open channel since it goes to the igniter ground which is open at this point. And the T2 from coil 1 is also not in the current loop since there is no SP -> T2 connection in the coils. The first coil tries to push from SP to T1 and the second coil pulls from T1 to SP. It's like a snake eating it's own tail and it makes a local current loop, feeding down over the first plug, through the head, up the second plug, through coil 2, across the connected T1 ports, and down coil 1 into the first plug again...

Now this is all speculation and I haven't wired it up yet. When I do, I suspect that I won't notice any difference. The proof, if there is any, will be that it works just as well as the other way and the benefit will be unnoticeable. But it will, in principle, reduce the current demand of the ignition circuit just a little and that'll please my sensibility.



Greetings -- I've been trying to validate this hypothesis before finalizing my own COP wiring. If T1 is indeed part of the SP circuit, then the idea of directly connecting the two T1 terminals is truly elegant. However, I'm so far unable to identify continuity between the SP terminal and either T1 or T2. Without continuity, the remaining possibility is an SP ground path through the coil laminates, bolts, mounting plate, valve cover and head. So, if the primary and secondary circuits are not electrically connected, then T1 and the chassis wiring are not carrying SP current and there is no advantage to the proposed wiring mod.

So, how can we be sure T1 is part of the secondary circuit (I've downloaded a copy of the Intrepid service manual and neither description nor wiring indicates the SP ground circuit, nor do the Mitsubishi's, perhaps implying grounding through the engine?) My attempts at continuity measurement via a hand DVM came up with an open circuit, but perhaps you have better information available. Did you actually determine T1-SP continuity yourself, or did you find that information in some documentation? Please get back to me on this, I'm trying to do this right !


Edited by TrevorS (08/01/12 09:00 PM)

Posts: 49 | From: Newark, DE | Member Since: 07/26/12 | IP: (108.2.184.201) | Report this post to a Moderator


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