1jz coils on a 7m, here's the wiring diagram

[bigaaron]

Well, between us running our business, 3 project vehicles of my own, and 4 project vehicles for customers, I have not had time to get much more progress on the 1j coils. I have had a little miss at high boost with this setup (20psi, and it was hot out and I was running pump gas) so I ordered a dc to dc converter to raise the voltage to the coils. This is the only cost effective way to increase the spark voltage. Like I said in the beginning, I did not want to have anyone waste their time or money building this until it was fully tested. It works well, but I do not think it is quite as good in terms of performance as the stock 7m coilpack. The nice thing is getting rid of the ugly coilpack and the ease of spark plug changes. You could use this dual ignitor setup with a gm style coilpack with longer spark plug wires and locate it near the shock tower, that would be another cool option.

I drew up a basic diagram, you can check it out at www.driftmotion.com

So like I said I would, I posted the diagram, and you can take it for what it's worth. I have several of the ic's and I have several ignitors available. I also have several sets of ignitor connectors so you can make it plug-n-pray. I can get the 1j coil connectors as two new 7m coilpack harnesses, but they are a little pricey. I do not have an extra set of 1j coils available.

 

[GrimJack]

Cool! Thanks for the info, it's nice to have options.

 

[bigaaron]

All those people who said I was such a jerk because I didn't post a diagram, what happened to you? Grimjack is the only one who has anything to say? I guess that's forums for you.

 

[figgie]

Silky Johnson present....h8t h8t h8t h8t.....

bigaaron, somehow i missed this thread yeterday but thanks for posting the diags. Now I hope you put a disclaimer on their incase someone does something and the engine blows up and says....ahh boohoo. it is because of bigaaron diag that i blew my motor. You know the typical,

"you try this mod at your own risk, There are no warraties either expressed or implied. If you blow your engine up with this mod, do not blame me. yada yada. "

 

[lagged]

All those people who said I was such a jerk because I didn't post a diagram, what happened to you? Grimjack is the only one who has anything to say? I guess that's forums for you.

i said you were a jerk for that. here i am! its nice to see you contribute finally! before you were just leaching.

 

[GrimJack]

Hey, what I have to say is important enough that nobody else should matter!

<sigh>

Ok, back to reality for the rest of the weekend...

 

[limequat]

I don't get it. Is the source driver there just to ensure you have enough current to drive 2 ignitors?

 

[bigaaron]

The ecu can not handle the current draw of the two ignitors in parallel. The ecu's output voltage drops to below 4v, the car will missfire and not run. You also must use the pulldown resistors to give the buffer ic a good high/low voltage swing as the ecu's ignitor output is floating.

I figured this out myself with an oscilliscope and sourced out the correct non-inverting buffer ic with 500ma output capability, yet there were several people claiming this was so simple and you could just parallel the ignitors. I still don't know what those idiots were claiming they helped me with, it had nothing to do with the electronics involved. But hey, I guess it's all water under the bridge now...

 

[mkIIIman089]

So, I must have missed it somewhere. But what is the benefit of using these coils?

 

[supradan22]

Yes I would also like too know this

 

[GrimJack]

Just the fact that you get coil on plug with your 7M, no more messy engine bay.

 

[bigaaron]

Yup, just like Grimjack said, it looks cleaner and eases spark plug changes. I can't honestly say it performs better then the stock coilpack though.

 

[figgie]

love the 7m with out the stock ignition coils on top. Cleans up the bay so much it is quite unbelievable.

 

[supra90turbo]

nice work, aaron.
now i just have to learn how to read a wiring diagram... hmm...

 

[chevyeater]

Better late than never. It does look nice installed.

 

[cjsupra90]

Looks good and nice and clean. No its not going to be as good as the stock coil set up. The JZ COP coils are only intended to be fired once per cycle. As wired as is to work with the stock Ign. system it fires as a waste spark (twice per cycle). By doing so, you are cutting the coil sturation in half which cuts the spark energy being that the coil can not fully charge...

I am not in anyway down grading the swap or setup. I think that it could benefit greatly with the addition of a CDI ign. system. An MSD DIS4 or something of equivlent would make it a great setup.

 

[IHI-RHC7]

Just out of curiosity, what happens if you were to wire up this setup with one ignitor, and run coils 1 and 6, 2 and 5, and 3 and 4 in series with one another? it would seem that with and ignition amplifier, such as MSD DIS4, AEM CDI, or HKS DLI, there would be plenty of power to run the coils like that. they would still be waisted spark, but it would seem to be much more simple to wire than multiple ignitors, an IC and a voltage regulator.

It looks great though.
-Jake

 

[Idealsupra]

Just out of curiosity, what happens if you were to wire up this setup with one ignitor, and run coils 1 and 6, 2 and 5, and 3 and 4 in series with one another? it would seem that with and ignition amplifier, such as MSD DIS4, AEM CDI, or HKS DLI, there would be plenty of power to run the coils like that. they would still be waisted spark, but it would seem to be much more simple to wire than multiple ignitors, an IC and a voltage regulator.

It looks great though.
-Jake

i think his whole idea was to do it WITHOUT and of the things you mentioned....

 

[IHI-RHC7]

well, He mentioned that there was a lack of spark energy anyway, so I would think that they would both benefit equally from the addition of such an ignition amplifier.
But I hear you.

 

[bigaaron]

I have heard several people say that the 1j coils do not work well with waste spark, but I think that is just info regurgitated from some unknown source, I will be testing the secondary voltage of both setups to see if there is a big difference. The miss I was experiencing could be totally unrelated because I had a small idle issue before I installed the new ignition system. What would make you believe that the stock coilpack with dual secondaries would be able to handle any higher frequency then the 1j cols? We are only talking about 6500rpm here.
They are both made with a similar design and materials, the 1j coil is just mounted on the plug. I would think that the coil mounted on the plug would be able to handle higher rpm because there is no extra impedance added from spark plug cables. Also, what makes you think that on a stock 1jz ignition system the ignitor output is actually on for any longer on a 7m? I do need to check this, I better dust off the o-scope again... There is a certain rise time but after that the coils would just overheat and the spark would not get any hotter.

All that aside, I made this work with all parts I already had. If I was going to spend $500+ on it I would use the dis-4. Not that many people are running 20+psi, this system is more then sufficent for a bpu mk3, and if you have the parts it's very inexpensive. Also, your tach will work exactly the same without using the 3 tach adaptors you would need with the dis4.

If anyone can prove me wrong on any of this then please, let's hear it. This is a "open source project" now, right?