Lexus 1UZ 4.0l V8 with MJLJ and COP's

cribbj · Post by **cribbj** » Mon Dec 17, 2007 8:28 pm

dr.occa wrote: we read the same write up in regards to the bmw COPs setup cribbj!

i borrowed your diagram and altered it for an EDIS 4 application (my application) and applied the in-series configuration. i have another EDIS4 module i could always hook up in parallel but am hoping the single EDIS will suffice. i also wasn't sure about the secondary grnds on the COPs so i did not address them in the attached diagram. any insight would be greatly appreciated.

Hehe, it seems we surf the same sites

The fellow who ran the BMW coils in series was good enough to reply to an email I sent him and he confirmed the circuit worked fine, and he hadn't encountered any misfiring at higher RPM's. Conventional wisdom would lead you to think since you've doubled the resistance, and halved the current, that perhaps there wouldn't be enough dwell time at high RPM to fully charge the coils, but maybe this isn't the case, or perhaps he just wasn't stressing the ignition system.

You mentioned secondary grounds on the COP's - what are you referring to? Is it possible your COP's have integral ignitors?

dr.occa · Post by **dr.occa** » Mon Dec 17, 2007 9:21 pm

cribbj wrote:
dr.occa wrote: we read the same write up in regards to the bmw COPs setup cribbj!

i borrowed your diagram and altered it for an EDIS 4 application (my application) and applied the in-series configuration. i have another EDIS4 module i could always hook up in parallel but am hoping the single EDIS will suffice. i also wasn't sure about the secondary grnds on the COPs so i did not address them in the attached diagram. any insight would be greatly appreciated.
Hehe, it seems we surf the same sites

The fellow who ran the BMW coils in series was good enough to reply to an email I sent him and he confirmed the circuit worked fine, and he hadn't encountered any misfiring at higher RPM's. Conventional wisdom would lead you to think since you've doubled the resistance, and halved the current, that perhaps there wouldn't be enough dwell time at high RPM to fully charge the coils, but maybe this isn't the case, or perhaps he just wasn't stressing the ignition system.

You mentioned secondary grounds on the COP's - what are you referring to? Is it possible your COP's have integral ignitors?

LOL! just as i started to reply to this post, Tim (the author of said article) responded back that he wired his up in like manner to my diagram. his COPs also cam with configured with 2ndary grnds which he connected to the nearest available grnd point in the engine bay.

I'm in the process of sourcing some toyota COPs and when I do finally get them, the 2ndary grnds may not be an issue.

cribbj · Post by **cribbj** » Mon Dec 17, 2007 9:45 pm

I have a number of Toyota Supra 2JZ-GTE COP's here, and they're just simple two terminal COP's. PM me if you're interested, and I'll make you a deal on 4 of them. What are these going into?

dr.occa · Post by **dr.occa** » Mon Dec 17, 2007 9:48 pm

cribbj wrote:I have a number of Toyota Supra 2JZ-GTE COP's here, and they're just simple two terminal COP's. PM me if you're interested, and I'll make you a deal on 4 of them. What are these going into?

they'd be going into a 4AGE dohc engine:

cribbj · Post by **cribbj** » Mon Dec 17, 2007 10:03 pm

Cool motor! I've just PM'd you back.

britlude · Post by **britlude** » Sun Dec 23, 2007 10:06 am

remember, in serial configuration the coils are only going to 'see' 6V...

sunray · Post by **sunray** » Sun Dec 23, 2007 9:49 pm

One thing to note is that the higher the cylinder pressures (ie: with higher rpm) then the higher the resistance that will be encountered to fire each spark plug. This would leave you with increasingly less reserve voltage to adequately fire each cylinder. I would think that if you are using a maximum dwell time too often with no reserve voltage then you may end up with some overheated coils. Its just a thought, but may not be the case in practice. You could confirm this pretty easily by hooking up a lab scope with some long leads and go for a road test with the scope next to you. watch the waveform and pay particular attention to the firing lines and then the dwell time through the rpm's.