Nissan VR38 ignition COP conversion
The ignition wiring harness on the NC is known to fail at the junction into the common harness for both COP’s and injectors. The wires going to each individual coil includes some sort of bulky looped wire for shielding/noise reduction which makes this a stiff non flexible lump. I have had one wire break as well as one of the COP fail, so replacing both have been on the list for a while.
Instead of messing with the stock harness I opted for a separate loom with new pigtails from Ballenger Motorsports and ran dedicated signal, power and ground. I spliced into the stock ignition PWR and GND leads in the fuse box to reuse the relay and fuse setup. Signal wires are directly from the EMS. I left the stock ignition harness as is for now.
For the harness I used only used bare wire crimps and did separate heat shrinking. I still hear people recommend soldering YET 100% of serious motor sport and OEM’s use crimps…. With a decent crimp tool and a bit of attention to detail non insulated wire to wire crimps and separate heat shrink is the way to go and I have never had one fail.
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For the coils I went with king of sparkness, the OEM VR38 aka Nissan R35 GTR COP’s. Same price as stock Mazda COP’s but supposedly have a death star amount (54mj) of spark energy, dwell, discharge and all the jazz. See testing and comparison of coils done by PRP for more info.
I tried finding OEM R35 coils locally but the market is saturated with fake coils, so I ordered directly from PRP in AUS. Ironically, there is not a single Nissan brand or OEM number on the coils I got but I have no doubt this is the real 54mj deal.
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The boots and springs needs to be carried over from the stock COP. There is also some kind of white magic pill in the R35 boot that I reused.
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The mounting tab is 45 deg off and 8mm higher than the Mazda layout. By chance it fits by rotating it and using a spacer, but a better option would be to fab up an offset alu adapter. The wires on number 4 is close to the cam position sensor but worked with the new loom.
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As for the dwell settings I used what PRP recommends here
My AEM Infinity has a 3D table which also includes RPM. Since the data from PRP only accounts for voltage I contacted them and got a reply that they can handle the dwell all across the RPM range. I have now run the coils for a couple of weeks including a trackday with no issues. Smooth sailing.
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