Modernizing the Nissan VG30DETT, Polar Engineering’s Ignition Upgrade

The VG30DETT found in the 300ZX Turbo had a state-of-the-art ignition system back in the early 90’s.  It had one of the first direct-fire, coil-on-plug ignition systems on a production car. This system was perfectly suited for power in the mid-500 whp range, after which you had to significantly close up your plug gap to avoid misfiring.  Polar Engineering has come up with a new ignition system using the coils from an R35 GT-R to significantly step up the Z’s ignition.

The heart of the system is 6 OEM Nissan VR38DETT coils.  These coils produce almost 3x the power of the original coil, enough juice to light off more than 1000hp worth of boost. The coils will allow you to run the stock plug gap to a much higher power level than the stock coils.  Being OEM coils, the GT-R coils are very reliable as well.  The coils come with the proper boots to work on the 300ZX heads.

The kit comes with a pair of CNC-cut mounting plates.  The plates move the coils out of the valve cover depression for better cooling while still allowing clearance for the stock intake manifold.  The mounting plates are powder-coated black.

Since the R35 coils are smart coils and can be triggered directly by the  ECU, they do not require a power transistor (ignitor) for ground-side triggering.  The power transistor is the most troublesome part of the OEM ignition.  The Polar Engineering kit comes with a jumper harness for eliminating the stock power transistor and six pigtail harnesses so you can modify your harness to use the R35 coils.

The kit comes with all of the bolts and spacers needed to adapt it to the VG30’s valve cover.

We look forward to the improvement in ignition performance that the P0lar Engineering kit will provide.  The ability to run wider plug gaps is going to improve driveability as well!  Stay tuned for more parts to being the VG30 up to date!


Polar Engineering




  1. Mike you don’t happen to have a primer on small gap vs big gap in relation to why, when, and how it relates to drivability, do you?

    1. Basically, a big gap has a larger spark and more easy ignition, but ignition systems have problems maintaining a spark with high cylinder pressure so typically you have to close down the gap on high-boost engines to reduce misfires under high load which reduces ignition reliably in general.

  2. There’s also a BDE R35 kit for the VG30. The core difference is that the BDE kit doesn’t require a plenum pull to change a spark plug or check compression. It places the coils in the stock VG coil location for easier maintenance.

    1. Also the BDE kit doesnt come with tiny spacers that can neatly drop into your spark plug hole during a routine compression/leakdown test or spark plug change.
      I have no affiliation with either company, but honestly one of these designs looks well thought out and usable (Human-Centered Design). The other is just a bunch of bolts, washers and spacers with a laser-cut plate that took 30 minutes to design on a weekend.

Leave a Reply

Your email address will not be published. Required fields are marked *