2JZ COP's on 7M-GTE

[MWebber]

I figured I'd post this up even though I'm not quite done with it.

I got the idea from one of the guys on sf.com (I think) printed up the wiring diagram (http://www.driftmotion.com/driftmotionignition.bmp) and soldered it together a few weeks ago.

Here's some preliminary pics. the second is the COP's finished, all that's left is to incorporate the new wires into the original harness and wire into the ignitors.

http://www.masupras.com/mike/06_mods005.jpg

http://www.masupras.com/mike/06_mods006.jpg

Mike

[BillyM]

Will still be fired in a waste-spark orientation?

You doin the whole stocker dual-ignitor gig?

What's the dwell-time on those suckers?

Different coils on different ignitors do one of two things, dont fully charge, or overcharge. If you so happen to find one of each from two different cars that works dead-on, go play the lottery right then. You really need to run something like that on a bench setup with an oscilloscope to make sure the dwell period is similar to stock.

...blame the megasquirt community for making me ornery about ignitors vs coils.

--BillyM

[MWebber]

Will still be fired in a waste-spark orientation?

You doin the whole stocker dual-ignitor gig?

What's the dwell-time on those suckers?

Different coils on different ignitors do one of two things, dont fully charge, or overcharge. If you so happen to find one of each from two different cars that works dead-on, go play the lottery right then.

--BillyM

in order...

yup

yup

dunno yet

that's what the line driver is for.

[BillyM]

Line driver will not change dwell time as needed for different specification coils.

...all it does is buffer between the ignitors and the ECU, so it wont have twice the load.

--BillyM

[MWebber]

Line driver will not change dwell time as needed for different specification coils.

...all it does is buffer between the ignitors and the ECU, so it wont have twice the load.



uhh... ok, if you say so.

just color me stupid then, when this was used with a single ignitor and no line driver there was not enough dwell time to charge the coil properly and would start breaking up ~2500-3000 rpm.

I've researched this for 3 months Billy, don't start the "I know more than you do" shit with me just because I haven't put out all the info I have about it. I don't strap shit to my car on someone else's say-so and hope for the best.

Mike

[BillyM]

Now now, I'm not playing any schlong-swinging "I'm right you're wrong" games. If you've researched this for 3 months, it should be very easy to explain to me how the dwell window is changed from stock coil needs to the cop charge-time needs. I don't know it all, and I've not looked into this further than 15-20min of searching so its very possible that there is some correction in there I'm not seeing, or you aren't telling us.

That drop-out was a function of the ECU not being able to switch the load of TWO ignitors correctly. With this buffer between the two ignitors and ecu, it will operate them to stock specification dwell timing. This may not be optimal for coils that are designed to fire half as often.

If you are going by "someone on a mk3 forum did it and it works, and I trust that" say so. ...but if you dont care to short-spark yourself, or want to burn up coils early, you might want to look into the things I'm mentioning. Honestly, your car, I could give two damns less if you have to replace your coils yearly or lose 30% of spark potential at the top-end due to incompatible dwell timing, but being a member of our community, and wanting only the best for us, I tend to ask those questions that require thought, work, and research beyond the norm.

...do with it what you will, just know I'm not here tot bust balls (like I usually am) but rather honestly curious to know more indepth information of the upsides and downsides of this setup. My first reaction was "damn those look hot... I want those on that 7m project car I've got in my bay" so don't think I'm not interested.

--BillyM

[MightyAl]

In support of Mr. Webber this has been argued to death on supramania.com. There was a thread on SF.com but the bulk of the discussion was done on SM.com. The system in this configuration has been running on a car for the past 6 months or so with no problems so far. If the life of the coils is decreased then it hasnt been realized yet. Considering the robustness of the coils I dont think there will be any reliability issues with this set up. I would like to do this but at the moment do not have the time or a reliably running car to test it on. I kindly donated a few parts to the cause on this car and am glad to see it coming together. I was wondering when you were going to post progress Mike.

[CarFreek]

Mike-Thats Damn Sexy-Ive seen Kawasaki COPs on top of a couple 7ms before-Any rough cost estimates/part # lists/Come over to my house and do this for free/ type stuff yet?-Again-Schweet job

[BillyM]

Al... that's great. ...it really is. But that doesn't change a thing.

My question, very simply put, IS THERE ANY MEASUREMENT OF THE NECESSARY DWELL TIME OF THE COP VS THE STOCK COILS?

I dont want "well it worked for so and so" ..that is not an acceptable answer for me. If noone has that, feel free to drop a "screw you billy, we dont know and dont care, so shut-it" ...or a "I'm not sure, what can I measure to get that information"

There are three things that can happen.

1.) 49% probability, coil will be undercharged, not get as much spark as it is capable of.
2.) 49% probability, coil will be overcharged, heats them suckers up, shortened lifespan
3.) 02% probability, coil will be perfectly matched (or very very close) in time needed to saturate, will work good with stock ignitors

...not trying to bust balls here guys, just want the low-down.

*edit*
I just read through every post BigAaron made on the topic. He refused to accept there are dwell-need differences between the two coils. I've come to the conclusion that he honestly does not grasp the theory of dwell at all and if you follow in his footsteps without question, you follow in the footsteps of ignorance.

http://www.tonyfoale.com/Articles/Ignition/Ignition_files/image009.jpg
Dwell IS real!

this is all I have to say on it until I hear further. If you have any desire to test to see that those coils are getting a full charge, let me know and I'll jump back into the conversation....
*/edit*

--billyM

[MightyAl]

If you are so hot about this then why dont you just do it yourself instead of demanding everyone else to answer your questions. Dwell doesnt mean anything...just get a little hotter spark in there and everything will be just fine. So are you going to keep posting time after time about dwell or are you going to check it out for yourself?


Al... that's great. ...it really is. But that doesn't change a thing.

My question, very simply put, IS THERE ANY MEASUREMENT OF THE NECESSARY DWELL TIME OF THE COP VS THE STOCK COILS?

I dont want "well it worked for so and so" ..that is not an acceptable answer for me. If noone has that, feel free to drop a "screw you billy, we dont know and dont care, so shut-it" ...or a "I'm not sure, what can I measure to get that information"

There are three things that can happen.

1.) 49% probability, coil will be undercharged, not get as much spark as it is capable of.
2.) 49% probability, coil will be overcharged, heats them suckers up, shortened lifespan
3.) 02% probability, coil will be perfectly matched (or very very close) in time needed to saturate, will work good with stock ignitors

...not trying to bust balls here guys, just want the low-down.

*edit*
I just read through every post BigAaron made on the topic. He refused to accept there are dwell-need differences between the two coils. I've come to the conclusion that he honestly does not grasp the theory of dwell at all and if you follow in his footsteps without question, you follow in the footsteps of ignorance.

http://www.tonyfoale.com/Articles/Ignition/Ignition_files/image009.jpg
Dwell IS real!

this is all I have to say on it until I hear further. If you have any desire to test to see that those coils are getting a full charge, let me know and I'll jump back into the conversation....
*/edit*

--billyM

[skeen550]

I saw this setup on the other mentioned forums as well and would like to do it myself given I have a FF intake manifold there is even less clutter on my valve covers and this COP setup would look very nice.

The thing is I dont want to loose performance or reliability of the stock system for looks alone.

I dont think the performance is degraded by the way BigAaron says his car runs but that of course does not give a solid answer to either question.

I applaud all those who attempt things of this nature and post the results for the community to reap the benfits from this venture.

But I do think Billy is asking ever so nicely (for him at least :) ) the right questions, I too would like to see the results of some dwell testing to set my mind at ease.

SCott

[lechner]

:stupid: "I applaud all those who attempt things of this nature and post the results for the community to reap the benfits from this venture." I also applaud those who ask the tough questions, point out stuff that doesn't quite sound right to them, and ultimately add to the overall knowledge base of this forum. Yeah, sometimes telling people that their months of research and hard work isn't quite complete cause they didn't know about Step X is seldom met with kind acceptance. But it should be.

Wouldn't you hate it if somebody suspected there was a better way to do something than how you are doing it, but they were afraid to say something because they feared you would get mad or tell them to go check it out for themselves if they want to know? Be careful of creating that type of environment here.

[MightyAl]

There is nothing wrong with asking the tough questions. But did anybody ask if the guy if he had a scope to check the dwell. So unless anyone wants to buck up I think you are all SOL. Like I keep saying, if you want to know the answers do it yourself. Don't look to others to come up with answers to your questions just because you want them to. I understand where you guys are coming from but the questions have been asked and it looks like they are not going to be answered. I am going to say it in the nicest way possible "get off you butt and do it yourself". I would never expect someone else to do my work for me. I was going to do this but since I am going standalone I can control the dwell so it doesnt matter for me. I offer the parts free of charge to build the buffer and no one has taken me up on it.

[BillyM]

...since people are showing intrest in the technical aspect of this and the technical reasoning these "drawbacks" that may or may not be present., I'm going to attach a PM I sent to al, which has a bit of data in there. M-Web, let me know if I need to cut it out brother, but know I'm just informing those others watching this thread, not trying to shoot anything down, infact I'm absolutely hopeful it will work out so I can do it too!

...and Al, yes, I did ask if he had access to a scope. In addition, I'm seeing what I can do to get a USB-based portable two-channel scope, if and when it comes through (those suckers are f'n pricey) I would gladly ship it out to Mike as soon as he's got it running.

---------------------------------------------------------------------
To: Al

You want to know why I don't blindly hop into a modification designed and made popular by someone who obviously does not even fully grasp the workings of an ignition system (talking about the guy on supramania/forums who designed that 'circut')? ...because I can not afford to. The only 7m car I work on is NOT my personal ride. I can not simply say "oh things aren't coming together correctly, you are going to have to pay for a $400 ignition amplifier, sorry." I don't have the option of installing a sub-optimal system in this car... Now, personal reasoning aside, lets get technical, ignore anything you already know, I'm not trying to talk down to anyone...

Firstly, I am no dummy. I don't think anyone in that conversation is, but I do think you guys are shielding your eyes to the blatant design character differences that SCREAM sub-optimal at first glance.

Ignition systems, open the flow through the coil's primary windings for a certain ammount of time where the voltage ramps up quickly as the magnetic field builds. When the pre-set ammount of time goes by, the circut is cut by the ignitor and flow stops, the magnetic field collapses and dissipates into the surrounding coil, where it grounds through the sparkplug gap. That ammount of time is the dwell.

Now... on the waste-spark 7m setup, the coils fire once every rotation. At 10krpm that is once every 0.006seconds. The engineers design the coil to charge, fire, and cool the coil all within that time period.

Now... on a coil-on-plug 1jz setup, the coils fire once every other rotation. At 10krpm that is once every 0.012seconds. The coil still sparks and cools as quickly as any other, but the engineers utilize the rest of the time increase in making the coils smaller. They are more dense and generally take longer to charge, but that's a liberty they can take, since they have twice as much time to work with.

...now, if you install those 1jz coils behind the 7m ignitors, the 7m ignitors are still only giving that flow/charge window needed by the stock coils (which logically speaking can be half as long as the 1jz coils need) The stock coils are good to 700-800odd horsepower. ...as are the 1jz coils, if you are only not charging these fully, you may well not notice any breaking up until 350-400hp. ...regardless, it can be sub-optimal, and a downgrade.

The other thing that can happen, but I doubt in this setup, is overcharging the coils, as was shown by the picture I linked in that thread, first one was WAY overcharged, 2/3rds of the amperage was passing off as heat into the coil itself, but that usually only happens when going the opposite direction of this modification.

------------------------------------------------------------------

...also, another chip you might want to check out is the 74HCT125. It is a line-driver/buffer chip made exactly for isolation and shit. It has a stronger non-inverted output with a pretty damn low propgation delay. Its not as suspectible to static charge or interference on the back-side as most chips either.

--BillyM

[MightyAl]

I am propbably going to use COP when I do my MS. I will scope it and see what the optimal dwell is when I get it up and running but that won't be for a few more months. Hopefully it will at least answer some of these questions.

[BillyM]

...and what do you do when you find out that the dwell isn't optimal? Do we have any EE's in the joint that can suggest how we'd go about implimenting some sorta timer circut or capacitive retainer that we can keep the circut open longer with (I think will be the necessary case) to extend the dwell period?

--BillyM

[MightyAl]

...and what do you do when you find out that the dwell isn't optimal? Do we have any EE's in the joint that can suggest how we'd go about implimenting some sorta timer circut or capacitive retainer that we can keep the circut open longer with (I think will be the necessary case) to extend the dwell period?

--BillyM

The dwell can be changed in MS or am I missing something here. If you are talking about the stock ecu then I would say everyone is hosed if the dwell isnt optimal which I can guarantee right now that it is not.

[BillyM]

Read straight over you having a MS... nevah-mind.

<--wee-todd-did

[canadian_psyko]

Endless reading various places, stumbled across:

Toyota Coil on Plug (Denso) 90919-02239 (COP).2.1mS
Toyota Dual Tower (Denso) 90919-02172.........2.8mS

From:
http://www.motec.com/tipsfixs/coilspec.txt

I'm pretty sure those are not the right part numbers (one looks to be a ?1g? and one a v6 maybe?), not a whole lot on google etc. But maybe give a rough idea on Toyota COP vs wasted spark dwell timings.

[BillyM]

Ok guys, I've been putting some time in on the circuit design, and behind that buffer chip, I am fairly certain I can design a flip-flop and clock combination as an adjustable "sustain" that will keep the circuit open longer after the ignitor signal from the ECU clicks off to allow for the longer charge period of the COP's (hopefully it will need a longer dwell, else we're boned). I am going to pick up Multisim from a buddy and in the next few weeks (finals) I will spend the time to build up and test the circuit, and once we get some measurements on those coils I can put together a writeup for this exact application on parts (looking at $5-10 for everything) and assembly instruction to match the dwells.

...and yes, I know that someone out there can probably do circuit design in their heads, but I'm electretarded, so this is big-stuff to me, hahaha.

Mike, do you have the part numbers for the ignitors, stock coilpacks, and the cop's you are using? I want to dig a little more and see if anyone has any dwell numbers out there, otherwise, I'll see about scoping the GTE coils and try to find someone who will let me borrow one of those COP's.

--BillyM

[MightyAl]

Billy,
All you gotta do is ask. I can get you a coil np. Shoot me your address and I can get it mailed out to you but it probably won't be until next week.

Below is a snippet from a thread over at msefi.com. This guy has gotten 4 or 5 7m's running on MS so I am assuming his dwell time of 2.6ms is accurate. Seems right in line for the stock coil packs. These are the settings to run the stock wasted spark coil packs on the 7m-gte.


Hi Rotarytoy

I run mine from VB921's

VB921 with 330 ohm resistors on pin 1 of the VB's[/b].
Straight to resistors R25, R26 & R28 on the side facing the CPU.
Dwell for the toyota coils MUST Be set to dwell control with
6.0 ms for cranking
2.6ms for running
Min discharge I play with 0.1

Trigger angle must be 86 degrees
+22.5 addition

Trigger A = 10
Trigg return = 0
Trigger B = 2
Trigg return = 0
Trigger C = 6
Trigg return = 0

This must be the sequence for wheel decoder otherwise strange dwell condition arises causing the VB' to seriously Overheat!!!

Earthing of the VB921's is connected directly a good earth on the Board itself something like the mounting holes in each corner of the board.
But remember to have sufficient earthing from the board to the Battery and the Motor.

Never ever popped a VB, Touch Wood!

Best Of Luck
Gordon.

[jtamulis]

Ok, I have a serious question for those who I will admit are WAY smarter than
I am on this topic. I read as much as I could, and I'll admit I'm COMPLETELY
lost.

BUT, I have the following parts in my spare parts bin, and I would LOVE to put
them all on my car, I'll be honest _I_ don't have ANY idea how to do it yet.
I know I could start playing and learning and such, but if someone here knows
how to do this, would you please PM or email me and tell me what I need to
do:

I have:
1x MSD Digital DIS-4 Brand new in the box with the 7M-GTE wiring harness
2x MSD Tach adapters (supposedly require for installation)
6x 1JZ-GTE COP off my 1JZ motor

Is this possible to make a MSD COP setup for my car, and if so does anyone
have the knowlege to do it. I'd be willing to pay for a wiring harness
plug and play, etc. I don't know how to make the MSD work on my car yet
but I also haven't played with it. I wanna really clean up my engine bay. I
don't NEED the COP, I just think it would look cool, I'd rather just use the DIS-4
if the COP is too difficult.

[MightyAl]

The only way to do it would be to put the coils in parallel. With the added energy from the MSD it should work ok. But then Billy will then yell at you because dwell will not be optimized for the COP's (much love billy). This is how a lot of MS users have done it in the past and many believe would work to bump the spark energy of the stock system to be able to run this way. It in no way would be optimal but definitely possible.




Ok, I have a serious question for those who I will admit are WAY smarter than
I am on this topic. I read as much as I could, and I'll admit I'm COMPLETELY
lost.

BUT, I have the following parts in my spare parts bin, and I would LOVE to put
them all on my car, I'll be honest _I_ don't have ANY idea how to do it yet.
I know I could start playing and learning and such, but if someone here knows
how to do this, would you please PM or email me and tell me what I need to
do:

I have:
1x MSD Digital DIS-4 Brand new in the box with the 7M-GTE wiring harness
2x MSD Tach adapters (supposedly require for installation)
6x 1JZ-GTE COP off my 1JZ motor

Is this possible to make a MSD COP setup for my car, and if so does anyone
have the knowlege to do it. I'd be willing to pay for a wiring harness
plug and play, etc. I don't know how to make the MSD work on my car yet
but I also haven't played with it. I wanna really clean up my engine bay. I
don't NEED the COP, I just think it would look cool, I'd rather just use the DIS-4
if the COP is too difficult.

[jtamulis]

ahh, I'll just install the MSD system, get it tuned and enjoy that. If you put the
covers on the engine, it looks pretty good, especially if you have a FFIM.

Time to start saving.

Jeff