Twin / Dual Ignition Coil Mod ?

[nappyroots827]

hey guys, this may sound really stupid, but if it is, sorry, just wondering...Anywho, the other day i was thinking of how i could increase the voltage output of my ignition coil, and i was thinking, it would be impossible to run two coils in series to double the voltage because the positive terminal of the second coil couldn't accept however many volts the first coil puts out...But then i was thinking, that you could run one coil per cylinder...If you run a wire from the contact on the dist. cap to the positive terminal of the coil, then the lead wire to the correct spark plug, then you could have one coil per cylinder, and if anything, it sure as hell would look cool :deal:

[A20A1]

Interesting let us know what you find.

[NXRacer]

you'll burn up the coil if your run them in series. The coils are only made to take a small voltage in and product a large output voltage. You do some serious damage if you hook them up in series.

I dont think you could rig up separate coils either because of the way the ignition system is setup. I dont know that you cant do it for a fact, but i'd think not.

[HostileJava]

As far as running them in series, I'm not sure that would work, i would think that the second coil wouldn't be able to handle the voltage from the first one, but it makes no sense to run one to each plug, first you'd have to somehow match when they fire electronically to your rev's instead of using a cap and rotor, secondly you are using the full voltage/ampreage of the coil each time a plug lights because the cap and rotor are basically switching the full current/voltage flow from one sparkplug to the next.

http://hostilejava.com/caprotor.JPG

The numbers represent plugs, the square thing is the coil, and the thick black peice inside the cap is the rotor, it rotates in the red indicated pattern discharging electricity from the cap into the plugs one by one and is driven by the engine.

I'm pretty sure that's how it all works, somone correct me if I'm wrong.

[AccordEpicenter]

too much current and too much risetime... you need a ignition amplifier, like a crane hi6 or msd 6A or 6AL or SCI... ive heard of others like jacobs too

[nappyroots827]

yeah i dunno, me and my friend are gonna try the experiment outside of a car, we have 4 accel super stock coils lyin around, and i have four spark plugs, and ignition wires, hes bringing his extra car battery, and were gonna wire it all up and try it out, if it doesn't work, o well, we tried, haha

[nappyroots827]

i don't see how it wouldn't work...Lets just say, if you run a 12v power source to the rotor, it would distribute a 12v charge to each contact in the cap, and you would run a wire from each contact to the positive of the coil, and when that positive signal is sent is when the circuit completes and the high voltage is sent out the lead wire to the plug...Atleast i thought thats how it worked, im not a genius with this stuff, i just didn't see why this idea wouldn't work...The only thing i could think of is that the coil isn't getting a constant 12v power supply so it might have charging problems but then i realized coils are inductors, and don't need to charge, they just immediatly transform the power...so i dunno, someone get back to me on this with ideas

[HostileJava]

i don't see how it wouldn't work...Lets just say, if you run a 12v power source to the rotor, it would distribute a 12v charge to each contact in the cap, and you would run a wire from each contact to the positive of the coil, and when that positive signal is sent is when the circuit completes and the high voltage is sent out the lead wire to the plug...Atleast i thought thats how it worked, im not a genius with this stuff, i just didn't see why this idea wouldn't work...The only thing i could think of is that the coil isn't getting a constant 12v power supply so it might have charging problems but then i realized coils are inductors, and don't need to charge, they just immediatly transform the power...so i dunno, someone get back to me on this with ideas

That might work, although I think the timing would be slightly off. But why do that? You are already getting the full voltage/current from the coil supplied to the plug, what difference will it make to have four supplying that same voltage current? Maybe I'm missing the advantage of doing this, can you elaborate on it? The only thing I see is more things to go wrong, more weight, and less space in the engine bay. When working on cars I think it's always best to live by KISS.

[night]

this really isnt worth the trouble unless you're just bored off your ass.
there are lots and lots of very high whp honda's running to 9000+ rpm on a single internal coil.

[NXRacer]

the rotor distributes the 20,000+volts that comes out of the coil and sends it to the spark plugs. the only way you could rig this up is to get the distributor to send the small voltage signal (like what comes INTO the coil) and then send it out to the separate coils that then go into each spark plug. Im not sure if a distributor will accurately control such a small voltage though.

[A20A1]

Coils have a charge time... elliminatig the charge time I guess helps get max out of each coil as RPMs increase?

I use the Accel Super Coil
Listed in the link below... It works better then the blaster 2 or accel super stock IMO

http://www.3geez.com/showpost.php?p=453748&postcount=6


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[HostileJava]

Coils have a charge time... elliminatig the charge time I guess helps get max out of each coil as RPMs increase?

To what end though? Is there any application out there that would require what little difference this would make and make it worth the effort put into it?

[maka_RTH]

you're basically describing a DIS setup, except still using the distributor... DIS usually has two or four coils, and they have more charge time becuase they don't fire as often.

[HostileJava]

Well then why not just switch to DIS, wasn't Sean selling a kit for that or was that somthign else?

[NXRacer]

a DIS system was something sean was 'selling' although i dont think he ever made more then the ones he used.

[A20A1]

I really don't know hostile...

Having multiple coils might allow you to run higher output coils which may inherintly come with a slower recharge time that is needed to build that extra power.

Like to say that the recharge time is a limiting factor to the output of the coil when using 1 coil to power all 4, 6, or 8 plugs.

I've notticed that coils have max RPM's untill they start dropping in power
and when switching from V8's to 4 cylinders the max RPM's increases.

[NXRacer]

i believe the point of having separate coils is just because there is no distributor so there is no way to distribute the voltage from one coil like the dizzy does. The coil packs that are used on DIS systems are much smaller then aftermarket coils (and most OEM coils). You get about the same power out of DIS, you just dont have the dizzy thats part of the ignition system.

[AccordEpicenter]

this really isnt worth the trouble unless you're just bored off your ass.
:sadwave:
what you guys are forgetting is that the rotor does not actually touch the cap... There is a small gap that the spark has to jump from the rotor to the cap terminals

[nappyroots827]

ive never seen a thread replied to so much in such a short time, i just took a shower and there were like 10 new posts, haha, well anyways, its starting to look like less and less of a good idea, i mean i have all the parts and im gonna try it out, and if it doesn't work, its just back to the old way...theres no other way to figure stuff out unless u try it....

[NXRacer]

i have a good idea. sell me one of your accel coils !! :D

[nappyroots827]

after i try it out, u can have it

[keruhas184]

Yeah, I would think a larger benifit would be running a quality aftermarket coil with an upgraded ignition system instead of trying to slap 2 or more coils with stock ignition.

[AccordEpicenter]

i have a good idea. sell me one of your accel coils !!

Wanna buy my super coil? She looks nice but doesnt work... what can i say, the yellow is soo rice

[NXRacer]

i have a super coil that doesnt work either. guess i should slap that on. at least it would match my crane wires...... :rolleyes:

:D

[Civvy]

The mk1 Mazda RX7 uses twin coils. Check out those forums!! if there was any further mods to that! That used a 4bbl carb and a dizzy.

[Bryan]

It's not like a capacitor or a battery. Say bye bye to the coil.

[nappyroots827]

hey, while on the subject of ignition, you know what feels bad that i did yesterday!!!??? Go lean on your fender with your left arm and touch an ignition wire end while the car is running, that made my heart skip a few beats, i thought i was gonna die, haha :stupid:

[Civvy]

lol. havent done that 4 a while

[Immeraufdemhund]

ahh yes the good ol way of checking for spark....

as for the coil thing i remember in my Digital Something class that we had this device that was a counter. Or it was a tiemr or seomthing. The point of this is that you need to have the voltage on the right coil untill it is supposed to discharge. You'd have the dizzy as the button that add's one or the next button you could say. all you'd need is a simple 2 bit adder or counter since there are 4 possibilities with 2 bits. i wish i remembered more about it caues we had to make a schematic that simulated a traffic light... same theory. Car stops on big white line.. Green light in supposedly 15sec....hmm i still have my old book i should look into it.

[A20A1]

lol, I tired to plug in a loose wire while the motor was running... I never made it.

Watashi wa baka desu

[Civvy]

Mike! remember me asking u about the rx7 4bbl carb? that had twin coils, did u have any paperwork or finds on that car? must be a good reason they used twin coils.
I just cant figure how they had it rigged, i'll look when i go get that 4bbl next time i'm up north.

[A20A1]

I dunno... what does the distributor run off of? maybe it ahs somehting to to with the fact they don't have cylinders... and what not

[Civvy]

True, i was aware that they're rotary and its fact i dont know shit bout rotary's.
I dont know i'll look nxt time i'm there or not??he,he

[Accordtheory]

I just don't understand the audacity of some people.. to think that they could actually improve the design of something when they don't even understand how it works in the first place. Fuck it, I guess I'l try to help with the understanding.. First, the coil is a negative trigger..that means that the + side has power whenever the ign is on, and the coil is triggered by the other side of the primary being connected and disconnected to ground, via the ignitor..the ignitor recieves it's trigger signal by a pickup in the distributor..so spark timing is not determined by the "contacts" in the dist cap, those aren't contacts at all, they are gaps between those conductors that the spark jumps on its way to the plugs, that is how the spark still goes if you change the timing electrically (basically analogous to changing the signal timing to the ignitor(MSD BTM,etc).. The only reason to have multiple coils is to eliminate the distributor completely..you can significantly increase the output from a stock coil by increasing the power to it with an ignition amplifier, this is totally different than what you would be doing by connecting 2 coils in series (An inductive transfer of power does not increase the power, it just changes the voltage/amperage ratio) whereas the ignition amplifier increases both..however I would never boost a stock coil, I would buy something like the crane hi-6 with the lx92 coil, that is more power than you will ever need, it should be able to fire much larger plug gaps with 20psi and h20 injection

[NXRacer]

i think the whole point was to discuss an idea that he had. IMO its good to bring up ideas and discuss them and if its something thats not good then we can (and did) describe why the idea wont work.

[nappyroots827]

yea, i wasn't saying this was gonna work off the bat, you gotta understand that we don't all know every little aspect of how a car works, thats the beauty of this forum, to learn about our cars and how they work so we don't have to pay a garage 400 dollars to change our oil...Its not supposed to be a place where people come out and insult people on their knowledge of cars...And i did learn something here, so lets keep learning and stop insulting

[Accordtheory]

I wasn't trying to be insulting. Obviously, people do come up with new ideas, all the time. However, the first step of trying to improve something is completely understanding how it works as it is. For those who think our cars today are complex, think about how complex automotive technology (or all technology for that matter) is going to be by the time we have grandkids...(im 23 now) then think about how many years they would have to go to school to learn enough to be able to come up with new innovations! Human lifespan will eventually get in the way of increasing knowledge, as you will only have so many years to learn...can you see a society so advanced that it would take 60 years of school to understand enough to be able to contribute anything?

[rjudgey]

if your really worried about ignition performance and want twin coils etc.etc. just stop beating about the bush and get Electromotive, crank fired and with a coil per pair of cylinders plus lots of additional extras p.s also so ECU setup for you FI boys where you can program your setup using a PDA!! How cool is that!! And they cater for Boys with NOS and Turbos with Retarding systems etc.etc.

[Civvy]

I just don't understand the audacity of some people.. to think that they could actually improve the design of something when they don't even understand how it works in the first place. Fuck it, I guess I'l try to help with the understanding.. First, the coil is a negative trigger..that means that the + side has power whenever the ign is on, and the coil is triggered by the other side of the primary being connected and disconnected to ground, via the ignitor..the ignitor recieves it's trigger signal by a pickup in the distributor..so spark timing is not determined by the "contacts" in the dist cap, those aren't contacts at all, they are gaps between those conductors that the spark jumps on its way to the plugs, that is how the spark still goes if you change the timing electrically (basically analogous to changing the signal timing to the ignitor(MSD BTM,etc).. The only reason to have multiple coils is to eliminate the distributor completely..you can significantly increase the output from a stock coil by increasing the power to it with an ignition amplifier, this is totally different than what you would be doing by connecting 2 coils in series (An inductive transfer of power does not increase the power, it just changes the voltage/amperage ratio) whereas the ignition amplifier increases both..however I would never boost a stock coil, I would buy something like the crane hi-6 with the lx92 coil, that is more power than you will ever need, it should be able to fire much larger plug gaps with 20psi and h20 injection

I dont think u understand either!!? Maserati,Mazda and many more used twin coils and they had distributors too!
I think the purpose of this thread was to find a cheaper method of increasing the performance of the stock ignition systems, which can be done and will be an advantage but, is out performed by todays aftermarket systems. :deal:

[FyreDaug]

So I ripped apart the parts car today because it finally ran outta gas. So I took the distributor off and swapped em (because I broke my vac advance, and zipties were holding it together) and took the ignition coil and wired it up in parallel to the input on the distributor. Better low end response was noticed right away. I re-gapped the plugs the ghetto way (they were dime size opening, now they are nickel) which I would say would be a 20 increase maybe.

Ive got a couple pics that ill upload and post in the next post, but it definately helped. Fires up right away too.

Couple things I will do next: Accel plug wires (+ 2 more for the coils) and thicker guage wire going into the coils (the factory one was split parallelely[sp]). But it does help :Owned2:

[FyreDaug]

pics:

Dual coils (http://www.cardomain.com/member_pages/show_image.pl?image=http://memimage.cardomain.net/member_images/4/web/808000-808999/808617_13_full.jpg)
2 in 1 (http://www.cardomain.com/member_pages/show_image.pl?image=http://memimage.cardomain.net/member_images/4/web/808000-808999/808617_14_full.jpg)
Ghetto engine bay (http://www.cardomain.com/member_pages/show_image.pl?image=http://memimage.cardomain.net/member_images/4/web/808000-808999/808617_15_full.jpg)

(if they arent up yet, just wait, CD is being slow)

Its all ghetto looking for now because this is my trial setups, seeing what works and what doesnt. But hey, you dont see it whats it matter for now anyways right?

[EricW]

intersting mod. What gave you the idea to do it?

[snoopyloopy]

so what exactly does it help and improve?

[gfrg88]

wouldnt it just be kind of the same as getting an aftermarket coil?

[AccordEpicenter]

im gonna guess youre gonna smoke an ignitor next, we will see, keep us posted

[w00tw00t111]

wouldnt it just be kind of the same as getting an aftermarket coil?
I was wondering the same thing. But what if you added two blaster2 coils? Would that honestly benefit you any?(if you don't really have any other mods)

[AccordEpicenter]

hmm.... well paralell they should get you more current for your spark (depending on the ignitor situation) which might help, and if you stacked them, say, coil output of one into the positive side of the other, thatd get you probably 50kv or so but i dont think the coils would last long, much less your distributor cap/rotor, but it would be cool to try.

[FyreDaug]

Well I'm all for theory and trying stuff. The rotor and cap were new <10000km ago (by me) and I dont think it would burn them out that fast. I'm sure it reduced life expectancy (as do most mods) but for a "free" mod I like it.

In comparison I guess I would say it was as effective as putting the intake on the car. It really only increases response and low end power (when it would normally bog), not really a power improvement, but a powerband smoother or something.

What inspired me? I donno, bored, and had a parts car lying around and by theory it would work. (And did)

EDIT: And by upping the power wire going to the coils I might see a little more improvement yet (since the factory one was... 14awg? I cant remember, which normally went to 1, now goes to 2. So thats tommorrows mod. 8awg.

[w00tw00t111]

Wow like a intake! Woo Hoo! I'm wanting to od that but, can't seem to find a civic air box.

With 2 Blaster coils do you think that it would be too much spark? Right now I just have one.

Also, you should right a how to with pics! I'm more of a picture person personally words are hard for me to follow. :)
I really wonder how much of an improvment that great of voltage would make.
Also, I have msd spark plug wires which are already really really thick 8.8mm I believe. So how would I join all those wires and get equivelent wires?

[FyreDaug]

Sure I'll do a quick how-to, I'll do it right now. The only pics I will have are those 3, but we'll see. Check the how-to later.

[FyreDaug]

I did this myself just from an idea and a theory I had. This would be cheaper than adding a high voltage coil (*EDIT* Stock appears to 45000V, so therefore you will run 90000V) And it was successful. I was asked to make this how-to, so here it is:

**NOTE: A few things that may be different with the way I installed mine and the way you will install yours are: My vacuum box is removed and I put an intake on. My car is 87 and the parts car was an 86.

Things you will need
10mm socket/wrench
Second factory ignition coil (I never tried this with aftermarket stuff so I dont know if they will be the same)
Soldering Iron
4 Spark plug wires (you should have all 4 already...)
2 Ignition coil wires (you should have 1)
Factory distributor
Distributor harness (that plugs into the coil, I cut it from the other distributor)
Electrical tape
Wire cutters/strippers
*butt connector or splice connector helps*

I dont have the best pics, but this is very straight forward.

Instructions
Step 1:
Disconnect negative battery terminal and decide where you will mount the secondary coil (I had my vacuum box removed on my car, and placed it beside the primary coil, towards the firewall. Only used 1 bolt to secure it (the one furthest back from the primary coil that it uses to mount it) It doesnt matter where you mount it, just make sure all the wires can reach
Step 2:
Disconnect all harnesses and the ignition coil to dist plug
Step 3:
Strip back ALL the wires on the harnesses already on the factory coil somewhere about an inch away from the harness clip.
Make sure you get some bare wire showing (about 3/4cm) so you can wrap the other wires from the secondary harness into it.
**Or if you have a splice/butt connector, I would suggest using that, as its much easier**
Step 4:
Shorten the secondary harness enough so you can plug it in to wherever you decide to mount the secondary coil and still be able to tap into the lines you have stripped back

**NOTE** On the coil, there is a little square box with 2 small gauge wires going into it, you do not need that for the secondary coil (I dont even know what it does, but its unneeded if you already have one)

Step 5:
Wrap the proper wires from the secondary onto the primary coil (Making sure the wires from 1 harness go into the wires of the same harness on the other coil, there are some wires the same color on both harnesses, DO NOT get these mixxed up)
Make sure the connection is really tight around them
Step 6: Solder the connections well and wrap them in electrical tape

You are done this part

**Making the 2 coil-to-dist wires merge together is a little harder. I used a variety of tools to get it to work, but in the end I decided that some side cutting wire cutters where the best bet**

Step 1: The 2 ends that would normally plug into the distributor will have to be modified. You will need to cut the "weather material" entirely off (the rubber piece that sticks around the end of the wires to secure it into place on the distributor) so it will look like just a straight wire.

Step 2: Cut back about 1cm on HALF the wire where the clip does not touch see pic (http://www.cardomain.com/member_pages/show_image.pl?image=http://memimage.cardomain.net/member_images/4/web/808000-808999/808617_16_full.jpg). You will need to do that twice. Make sure you save one of the clamps from the ends you are cutting, you will re-use it again, so be careful.

Step 3: Once you have them both cut back with both clips being able to touch in the center, then face outwards away from each other on opposite ends, tape the wire about an inch or so back to keep them in this position so you can put the clamp back on it.

Step 4: Carefully put the clamp back on the ends, making sure that both "clip" wire pieces are being held securely by the clamp. And clamp the crap outta that thing and make sure its tight. Then tape it up, leaving about 40-50% of the clamp showing (tape the rest really tight). You need to leave some showing to make a good connection inside the distributor.

Step 5:DOUBLE CHECK YOUR WORK, make sure both harnesses are tapped into the proper harnesses on the primary before you go any further. If not, GO BACK and do it again. Plug all the harnesses back in and connect the negative of the battery.

Step 6: Try 1 coil at a time to make sure it will run off of either one. Do this by having all the harnesses plugged in and having 1 of the 2 coil wires unplugged from its respective coil. Make sure to have the unplugged one away from any grounds or any eletrical equipment as it will become a live wire once you start the car. If the car runs with 1 coil connected, turn the car off, unplug that one and plug the other one in. (this will test both coils, and the connection you made inside the distributor with the 2in1) If the car starts with either of them. Turn the car off and plug them both in.

Step 7: Now that the car runs you can open the gap in the spark plugs a little, this will help them from over heating as much since they will run hotter with twice the power, with twice the power you can open the gap a little more and get a little more efficient burning spark. This step is not neccesary after I did the dual coil I didnt change the gap until later. I didnt notice any difference with the re-gap. But its probably a good idea.

A couple recommendations that will make this even better:
New cap/rotor
New performance wires for the plugs (not needed for the coil to dist, since you just made your own, but it may help and it will give you another chance if you screwed up the 2in1) **note you will need an extra coil wire, as Im sure the kits only come with 1**
New plugs, I'm sure this would be a good chance to splurge on some iridium ones, but its unneccesary. I have NGK platinums but I hear the copper cheaper ones are better anyways.

**And for you advanced performance people**
Run a relay off somewhere in the fuse box that is only on when the car is on and re-do the power wires going to the ignition coils with thicker guage wires. I think its 12-14 gauge stock, so 8awg wouldnt be a bad idea.
I havent done this yet, but I will be shortly, you will need to find which of the 2 thick wires in either harness is the hot wire going to it and redo the wire directly into the harness with the thicker wire. Or if you wanted to go the cheaper route which could potentially be the same do this:

Where the 2 wires are spliced together for the hot, cut them both free, and solder them together with the 8awg wire. Because you have 2 coils running off the same wire which was only meant for one. You are drawing twice the power, so a thicker cable going to where they split cant do any harm.

This last step I have not done so I wouldnt suggest it unless you know what you are doing.

How I rate this mod:
You wont see a whole lot of increase in this, but it was free for me (off my parts car) and I'm sure itll cost maybe 10 bucks for you at a wrecker, so in my books, its worth it.

Low end response was greatly improved, especially low rpms 1000-1500 range where I would normally bog doesnt bog (or not as much)
Throttle response all throughout was increased and the engine seems to rev a little quicker, but I cant say for sure
Depending on the engine (Im a20a1) you might get more increase with an FI car, but I wouldnt say it makes much more power, it will feel like it, and the spark will obviously be hotter so your mixture is burning better. You should see some more effciency out of your gas milage though.
The car fires over quicker when its cold, and takes 1 quick flick of the wrist when its warm to start.

I would rate this mod for gains as much as I would with adding my intake, the intake makes more power, but the ignition smooths out the power band and like I said, more low end response definately.

So the final step is take a drive!

pic 1 (http://www.cardomain.com/member_pages/show_image.pl?image=http://memimage.cardomain.net/member_images/4/web/808000-808999/808617_13_full.jpg)
pic 2 (http://www.cardomain.com/member_pages/show_image.pl?image=http://memimage.cardomain.net/member_images/4/web/808000-808999/808617_14_full.jpg)
pic 3 (http://www.cardomain.com/member_pages/show_image.pl?image=http://memimage.cardomain.net/member_images/4/web/808000-808999/808617_15_full.jpg)
pic 4 (http://www.cardomain.com/member_pages/show_image.pl?image=http://memimage.cardomain.net/member_images/4/web/808000-808999/808617_16_full.jpg)

EDIT: And one more thing I forgot to mention, if you regap your plugs I would advance the timing a couple degrees. I went up by 3-4 degrees and it helped on top of the ignition

EDIT2: It appears (according to my cheap ass multimeter) that each stock coil is 45000V (not 30000 as Ive been told, and as some upgraded ignition modules say) So therefore you will be running 90000V this way. Advancing ignition timing is a good idea, it made quite the difference aswell. I can spin all through first on pavement now. And squak second no problem. (I checked each one individually with 1 connected so the engien ran, got 45000 each) I'm not quite sure how to check the output properly, unless I jam something in the coil-to-dist somewhere to check it. But I will try again later tonight. Break is over at work. But it definately helps, whether or not its at a true 90000 I will find out later.

[POS carb]

:bong:

[A20A1]

Can you check the output by removing a spark plug wire and pluggin the meter into one of the 4 wire ports and grounding the other end? can the meter handle that much input?

[FyreDaug]

Thats a good idea, I'll give it a shot before I go to work tonight. But each one (by itself) was infact 45000V

[FyreDaug]

Well after electricuting myself 4 times I decided I cant properly test the total output, its an old needle style multimeter and normally it stops at 45000 for each one, every time before I ended up dropping the meter from electricity I saw it go past 45000. I dont know how else to test it, but obviously it would be double.

[mouchyn]

lol.

dude, spend the $15 and take it to a shop. they can hook it up to an ignition diagnostic machine and tell you spark voltage, duration, quality, temperature, everything.

or, you can wear rubber dish gloves and borrow a better meter.

whateva.

[mouchyn]

the ignition coils for the 3G prelude look very similar to the accord coils. hmmmm. i have a box full of prelude ignition parts. i wonder if i could rig up a couple prelude coils like you did.

i'll have to check that out.

poor mans ignition upgrade. i love it!

[Mike's89AccordLX]

Hmm I do have 2 accel super stock coils lying around maybe I will do this...

[Civvy]

Dont mean to dis the idea cos i love it, but, altho a powerfull whack is good for performance and economy ....when u need it.
Conversely.....when u dont need it and are just crusing, the too-hot spark will surely cause engine knock and thus bad economy.

[FyreDaug]

I havent had any engine knocking and Ive ran a full tank through it.

I was beating on it a little harder because I liked the power increase and I still got the same milage (500km) as I normally do when I drive it nicer. This tank I'll be nice and see how much I can get out of it. Normally when I beat on it I fill up at 480, so maybe another 20km outta the tank.

[FyreDaug]

Should this be moved to the how to section?

[mouchyn]

it's not exactly a "how-to" yet...

[FyreDaug]

How isnt it? Its complete directions on how to do it.

[modu03]

those coils shouldn't be able to produce more than 30,000 volts a piece, so your lookin at about a maximum output of 60,000 volts....

but you have to consider the fact that with two coils, you are also doubling the resistance, which means that there will be a drop in amperage... high electricity is good, but you want good amperage too...

why not just spend $40 on a blaster ss coil... puts out 40,000 volt and has extremely low resistance for better initial spark plug gap jumping... i had this on my car, you can feel the difference in power...

[A20A1]

Coil Turns Ratio / Voltage & Current
By winding more turns of wire on the secondary coil than on the primary coil, a voltage step-up can be produced.
The degree of voltage step that can be induced in the ignition coil is generally proportional to turns ratio.
Example: 100 secondary turns for every 1 primary turn is a 100:1 turn ratio
250 volts "in" will produce 25,000 volts "out" given a 100:1 turns ratio.
Increase voltage step by increasing the turn ratio
Too high a tun ratio and secondary voltage can drop.
As voltage output is increased, the current output is decreased.
As turn ratio is increased, other electronic properties are affected, such as resistance, reactance, and impedance.
The best high performance coil is not usually one with just a high turn ratio.
And more voltage isn't always better if you lose amps/current. Have a sufficeint amount of Voltage to bridge the gap under the conditions the motor will be running, such as High comp, Nitrous, turbo. And if applicable, a quick enough charge/rise time to handle high rpms.

Coil Resistance and Resistored Plugs / Spark Duration
Primary and secondary resistance seems to affect SPARK DURATION
Spark duration is good for Low RPM, just as the resistor in the spark plugs also aides in increasing SPARK DURATION

There are Resistorless spark plugs are for high rpm cars (4,000 -10,000+ RPM) where long spark duration is not required. For motors below 3,600 rpm the added duration from the resistor in the plug allows the coil to bleed the power more slowly increasing the spark durration, however the spark is weaker. The volatage required to bridge the spark gap is the same between resistorless and resistor plugs, assuming the materials are the same. The resistor comes into play after the plug fires.

High rpm coils I've seen have turn ratios of close to 130:1 , while most other coils use 100:1 or 80:1 You can see how the higher Primary and secondary resistance increases spark duration by looking at the Mallory High RPM Coil Specs compared with MSD specs.
Mallory High RPM Promaster Coil
129:1
67,000v
Primary Resistance: 0.500 ohms / Secondary Resistance: 12.5K ohms
Spark Duration: 450 uS


Other things I'd like to note
I've found it better running with a
Super coil
70:1
45,000v
Primary resistance: 0.700k ohms / Secondary resistance: 11.8k ohms
Spark Duration: Accel says it's supposed to be longer

then with a

Accel Super Stock
95:1
42,000v
Primary resistance: 1.400k ohms / Secondary resistance: 9.2k ohms
Spark Duration: ???

or

Blaster 2
100:1
45,000v
Primary resistance: 0.700k ohms / Secondary resistance: 4.70k ohms
Spark Duration: 350 uS

Surprisingly the Super stock kept up with the RPM's... however the coil was ment for a V8 with twice as many cylinders then our motor so technically we have double the usable RPM of the coil.

My second choice in a coil would have been the
Blaster SS
70:1
40,000v
Primary resistance: 0.355k ohms / Secondary resistance: 4.40k ohms
Spark Duration: 220 uS

I'm also assuming lower turn ratio migh have helped in running with the added resistance of my platinum +4's, but I dunno for sure, especially since the coil still puts out high voltage with less turns then other coils... but it's twice the size... hmm.

[A20A1]

Do you think that the coil manufactures are balancing low rpm power with the added resistance for increased duration with the higher turn ratio for higher operating rpms and voltage? Sound like this is the case looking over all the info I collected.

Still that Mallory coil seems a bit much. Id rather have presumably a higher current with my Accel super coil then pile on more voltage with the Mallory that I don't think I'd need.

Is this the correct resistance for our stock coil?
Accord Stock Coil
?:1 ratio
30,000v ?
Primary resistance: 1.2k -1.5k ohms / Secodary Resistance: 9.0k -13.6k ohms

It looks very simmilar to the Accel Super Stock Coil specs. As people have mentioned before it's not much better then stock, but its worth it if you're in need of a replacement coil.

[kcaudill]

Testing ignition coils is tricky. There are many varibles that can change the amount of output a coil can produce. Testing a coil without a spark plug and the compression of the engine will definatly produce a high coil output. I have tested automotive coil in exsess of 70kv in the unloaded state (no plug or engine compression). This in turn over heated the coil very quickly and burn the secondary side of the coil resulting in an inoperable coil. However when the coil was loaded (with plug and engine compression) the same coil only produced around 35~37kv. This is sort of a capacitive effect. If you truely want to find the true output of an ignition coil you must use an oslliscope and a 1000:1 high voltage probe.

A20A1
The resistance usually on the coils are :
Primary (low voltage incoming to the coil) Around 2ohms and under. The primary is just a thick gauge wire, maybe 14~16 awg wraped around a bobin many times.
The secondary resistance is usaully 8~20 kohms this wire is around .05mm thick wire wraped around a bobin where the primary bobin is placed into, then the whole assembly usually has a iron core to make the characteristis of the coil.

If you look at a coil with a o-scope, you will see a +10kv rise in voltage then a sharp -20kv drop in voltage then back to a "coil ringing" to 0 vdc. This is a normal coil characteristic.

Other contributing factors is the duty cycle (spark duration) and amount of volatage of the input to the coil. You can almost figure what the output is by measureing the input and multpliy by 1000 . This only works if the coil has an external igntion modual. Older GM cars with the HEI igntion has this, the HEI is inside the distributer, flat, half round, with four conections. This module takes in info for timeing and battery voltage to output around 50vdc with a duty cycle of less than 1% giving the coil a pluse. This pluse triggers the coil to produce an output around 37kv.

Hope this does not muddy the water any.

[A20A1]

More info the better. :)

[kcaudill]

Sorry if to winded, I am a Electronic Engineer at a facility that manufactures ignition coils and spark plugs for Chystler, Honda, Toyota, GM.

[FyreDaug]

I was getting between 4 and 5 (x10000) for the output of voltage.

Since they are both wired into 1, the resistance should drop will it not? Wired in parallel?

[kcaudill]

Yes the resistance will drop, however the current drawn through the wiring will also double on the primary side! ie. two coils with a resistance of 10 kohms and a current drawn of 1 amp each, when wired in parallel there combined resistance will be 5kohms and an amperage draw of 2 amps. These are using hypothetical numbers.

[FyreDaug]

All I know is it made a difference when it was wired up...

[FyreDaug]

I will probably try it this summer with 2 accel coils or something. Just to be different and to try the risks I wanna do it.

[Accordtheory]

How do you isolate the second coil's secondary winding from ground to connect the 2 coil's secondaries in series? If you haven't done that, you've connected them in parallel, which will Not produce a higher output voltage. I=V/R, if you want more amperage, you must either upgrade your coil to one with a higher voltage output, or lower the resistance of your plug wires, or both.

[FyreDaug]

If its wired in parallel it should get double the output right? It did make a low end difference...

EDIT: And keep in mind each one measured 45000V, not sure how if stock is 30000 apparently, but the meter read in between 4 and 5 (x10000)

[kcaudill]

If using a higher performance coil with a longer spark duration will achive the same results in using 2 coils without the hastle. I use a Jacobs Igntion module with an external igniter. Very easy to use, plug your exsisting coil wire from the dist. to the input to the Jacobs, then the output of the Jacobs to the dist. The performance gain that I did see is in the low to mid-range hp and torque.
FryeDaug:
did you measure on an unloaded coil?

[Accordtheory]

If its wired in parallel it should get double the output right? It did make a low end difference...
Connecting 2 batteries in parallel doubles the available amperage, not the voltage. Amperage flow through is circuit is Voltage divided by resistance. So if you double the available amperage, you won't have double the flow, but you might have more actual power flowing through the circuit due to reduced voltage drop under load. (like swapping a 200 amp battery that drops to 10 volts when you're trying to start the car with an 800 amp battery that only drops to like 12.2) But I think a far more effective way to achieve a more powerful spark would be to use plug wires with a much lower resistance.

[kcaudill]

Connecting 2 batteries in parallel doubles the available amperage, not the voltage. Amperage flow through is circuit is Voltage divided by resistance. So if you double the available amperage, you won't have double the flow, but you might have more actual power flowing through the circuit due to reduced voltage drop under load. (like swapping a 200 amp battery that drops to 10 volts when you're trying to start the car with an 800 amp battery that only drops to like 12.2) But I think a far more effective way to achieve a more powerful spark would be to use plug wires with a much lower resistance.

Correct, never claimed that the addtion of a second coil adds voltage to the system, just more amperage to jump the air gap of the spark plug. To double the voltage you would have to run the coils in series, then the problems of containing the voltage will become the main problem.

[FyreDaug]

Hmm. Yes I did measure an unloaded coil, I pulled 1 coil to dist wire while the car was running (so it would run off the other one) and measured the one disconnected, showing 45000V.

So if this isnt doubling the current going to it, what is it doing and why did it help low end? Thats kind of what baffles me, I also regapped the plugs larger with no losses. I love the way this car pulls.

[FyreDaug]

How come I get better low end response? If this is technically not doing anything I would like an explanation as to why I got low end response.

[Civvy]

Anyone seen this b4?
http://www.performancedistributors.com/batteries.htm

[kcaudill]

You are getting a hotter spark, higher amps, this will ignite the air/fuel mixture better, this in turn will burn more of the air/fuel mixture in the cylinder and in theory lower your cat temps also. I would compare it to using a high octane fuel