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Jul 7, 2016

Nissan Skyline GT-R Ignition Coils, Ignition Boosters , Igniters, and Spark Plugs, and Ignition Troubleshooting

R34 N1 Super Taikyu

Ignition and the ignition system. When you have a misfire, on an engine, you effectively are losing the horsepower for that cylinder, wasting fuel, and potentially causing damage to the engine.

There are two types of coils, ignition systems on a stock RB26DETT, the R32/R33, and the R34. The coils on the R32/R33 are the same, both have an external igniter. The R34 have a built in igniter (same as series 2 RB25).

NISMO R32 GT-R stock coils

We have heard that the stock coil output is 45kV. However we haven't seen any confirmation on that number. A coil on plug setup like an RB26 is superior to a normal coil/distributor cap, as each coil has more time to charge and discharge, cool off, vs a single coil setup. It also allows direct control of coil dwell time, and firing time.

The coil is the other end of a harsh environment. In the combustion chamber, where the spark plug has to fire, is a bad operating environment. It probably should be against OSHA.

This is where the correct spark plug comes in. We have heard, that it takes 5,000 less volts to fire an iridium spark plug vs a conventional plug. Copper is a great conductor, however it wears much faster than other types of metals. We prefer the double fine wire racing iridium. Some people like changing plugs every week. Some people don't like the iridium, we have been using them for more than 15 years in high performance vehicles. NISMO race car mechanics recommended the double fine wire iridiums to us, and we trust what they have to say.

Double fine wire, NGK Racing iridium spark plug

(Watts / centimeter*Kelvin) Thermal Conductivity
Copper = 4.01
Aluminum = 2.37
Iridium = 1.47
Zinc = 1.16
Steel = 0.70 - 0.82
Platinum = 0.716

Stock Spark Plug for an RB26DETT

* P = Premium platinum
* F = 14, 19mm(3/4") reach, 16mm (5/8") hex
* R = Resistor
* 6 = Heat range 6
* A = Firing end construction
* -11 = 1.1mm gap (0.044")
Heat range for NGK plugs 2 HOT - 11 Cold

Spark plug gap. The "gap" is the distance between the ground electrode and center electrode. The further the two are apart, the more potential (voltage) that is required to arc, or jump that gap. Some people run a super tight gap, because of misfire issues. If the car is pretty stock, then it should have no issue arcing or firing across 1.1 mm or 0.044 inch. At bigger power you might go down to 0.8 mm or 0.031 inch. Generally a bigger arc is going to give you a more complete burn in the combustion chamber. 

This is from NGK on spark plug gap.

"Although the NGK factory will set the gap to a preselected setting, this may not be the right gap for your particular engine. The incorrect plug gap for your engine can contribute to a high rate of misfires, loss of power, plug fouling, poor fuel economy and accelerated plug wear. It is always best to check the gap against the manufacturer's specifications. If adjusting the gap on fine wire or precious metal plugs such as platinum or iridium, be very careful not to apply any pressure or prying force to the fine wire center electrode or insulator as they can be damaged. The gap should be adjusted by only moving the ground electrode. 

Another consideration that should be taken into account is the extent of any modifications that you may have made to the engine. As an example, when you raise compression or add forced induction (a turbo system, nitrous or supercharger kit) you must reduce the gap (about .004" for every 50 hp you add). However, when you add a high power ignition system (such as those offered by MSD, Crane, Nology) you can open the gap from .002-.005"."

A good stock replacement spark plug for an RB26 is a BCPR7EIX. Its an NGK Iridium plug. Heat range is 7 which is one heat range cooler than stock. Its readily available in the US. I would use them up to about 500 horsepower on an RB26. Above that I would look at an 8 for a street car, cooler if its a track car.

More spark plug information here - RB26DETT Spark Plugs

Back to the ignition, coils, wires, etc. The first thing to do, if you think you have a misfire, or problem with your ignition system is to observe.

1) Does the car have a noticeable miss? Shaking a little, won't rev up correctly? An RB26 should idle pretty smoothly at 950-1050 rpm.

2)Can you rule out anything obvious? Aka vacuum noise, vacuum lines off, intercooler hose popped off, electrical connections disconnected?

3) Remove center plate from engine - finishing plate, so you can access coils.

4) Reconnect igniter. Start engine. Disconnect one coil at a time, to isolate cylinder that is misfiring. If you notice no difference, then double check them all. There is another way to do this with Consult software, but standing in front of the engine, its normally very obvious which cylinder has little to no change when disconnected.

5)When you locate the misfire, turn off engine. Pull that coil and plug. Double check all connections. Is the connector damaged? Any signs of overheating on the coil? Is it dirty? Do you see a large amount of carbon? Check the wiring harness. Any loose or broken connectors?

Missing part of the connector

6)Pull the coil boot off, look at the contact. There are two styles of contact, a carbon, and a spring. The carbons wear, the springs can also fall out. Make sure something is there, and doesn't look corroded, or damaged.
Notice anything missing? High boost, and RPM misfire identified!

7)Pull the spark plug out and look at it. Does it look normal? Does it have wet fuel on it? Is it missing an electrode?

8) Clean or replace spark plug. Recommend replace, but that isn't always practical

9) Clean and put dielectric grease on the boots

10) Fire it up, see if that fixed it.

11) If it fixed it, then you are golden. If not, then continue

12) If the car is an R32/R33 then it has coil, igniter, wiring harness, ECU, power to fire the coils. If the car is running, the power is good, so don't bother look at the main power. That narrows it down to coil, igniter, wiring harness, ECU.

13) Next thing to try, is figure out if the coil is bad. Take the coil that showed as misfiring, and move it to another cylinder. AKA #2 was bad, move it to #3, or #1. Doesn't matter where. Did the misfire follow that coil, or is it still showing same hole as bad?

14) If the misfire followed the coil, then its probably a bad coil, replace, test again.

15) If the misfire stayed in the same location, then its either wiring harness, igniter, or ECU. Could also possibly be bad plug. Swap plug, test again.

Check out the center pin on this connector. Wiring harness

16) The last two cars I had this issue with, turned out to be fixed by removing the wiring harness from the ECU in the passenger side kickpanel, and reseating the ECU connector. It was that simple. Both cars started firing on six cylinders again

17) If this doesn't fix it, the next step is isolating the wiring harness, the igniter,and the ECU to figure out which component isn't working.

Stock Coils


  • You already have them
  • No extra cost
  • 45kV output (according to our Nissan sources)
  • R32/R33 22433-60U01  or 22433-60U02
    • The front two coils on a early 90's Infiniti Q45 are the same
  • R34 22448-25U00 (coil assy)
  • R34 22465-59S00 (boot)


Stock coils showing signs of water in the engine valley
Aftermarket Coils

  • Possibly higher kV output
  • Possibly less parts


  • Cost
  • Added complexity in some cases
  • Could be worse than stock
  • Could be Chinese made junk
Drop in Aftermarket Coils
  • Splitfire
    • Have been around many years
    • Tried them, prefer stock
    • Pretty blue if that turns you on
    • New parts generally fix issues by covering them
  • Yellow Jackets
    • Chinese knock offs, Alibaba specials
    • Probably worse than stock
  • Red
    • Chinese knock offs, Alibaba specials
    • Probably worse than stock
Stock Wiring harness

  • Gets crispy in the engine valley
  • Check connectors for broken tabs
  • Check connectors for broken inserts
  • R32, R33, and R34 GT-R are all unique. One of the few parts on these cars that are
  • Grounds are important. The older the car, the worse the grounds get. Take them all off, wire brush, clean, and reassemble. Grounding kits really do help.
  • Electricity is lazy, and takes the path of least resistance

  • LS2 Q9 coils to RB26DETT
  • R32 Coil Wiring Harness
    • R32/R33 to R34 Coil
      • This Wiring Specialties coil pack sub-harness is plug and play to the R32/R33 RB26 OEM harness. Make the install very simple and make more power instantly. 

        • Allows for R34 Smart-Coil mounting in the OEM coil location for R32 and R33 applications
        • Plug and Play
        • Harness eliminates the ignition chip

    • R32 Pro Harness
      • Brand NEW Construction
      • High Temp Nylon looming with adhesive shrink tubing
      • High Temp wire (280 degrees)
      • OEM connector specs (no cheap aftermarket connectors that fall apart)
      • Designed for a factory-like installation
      • OEM wiring connections and 'T' junctions. No soldered connections at all
      • Fully tested after production for an easy plug-and-play replacement
  • R33 Coil Wiring Harness
    • Brand NEW Construction
    • High Temp Nylon looming with adhesive shrink tubing
    • High Temp wire (280 degrees)
    • OEM connector specs (no cheap aftermarket connectors that fall apart)
    • Designed for a factory-like installation
    • OEM wiring connections and 'T' junctions. No soldered connections at all
    • Fully tested after production for an easy plug-and-play replacement

Battery direct harness. About $180. Takes battery voltage though a relay directly to the ignition coils. We never did a before and after test, but will have to one day. 

HKS Twin Power

  • A compounding ignition system of full transistor type + CDI (Capacitive Discharge Ignition) type which is an ideal performance in a wide range of engine speeds from low RPM to high RPM.This system will improve in starting, more torque at low and medium speed range, reliable ignition in high boost pressure, and better response.
  • This is a compact and lightweight, so it can be mounted anywhere. In addition, because of high efficiency power circuit, we were able to keep to a minimum level of impact on the alternator. And we offer a broad range of products for installation to your vehicle.
  • Because of the high power, engine tune-up can cause a trouble in ignition or starting failure. This system is ideal for those cases, and also best for those who have idling problem or people want the NA vehicle power-up.

    *Full transistor type: It has long duration of discharge and could obtain stable combustion at a low RPM
    *CDI System: It has fast initial rise of current discharge so it has strong ignition energy which is good for high RPM.

B&M New Volt
     Voltage booster.  They have been discontinued for a long time, however there are similar boxes that are used to increase voltage to fuel pumps.  The more voltage you have going into a coil, the more voltage it is going to put out. More or less. 

Igniter Modifications
  • Z32 Ignitor

Some wiring modifications

More wiring modifications and new harnesses for RB26dett

Understanding, Testing and Calibration of Ignition Coil Dwell Time

Supertec R35 Coil adaptor for RB26

  • R35 Coils
    • Adapters available
    • OEM Nissan parts
    • Proven to 1500+ hp
    • May be able to use other Nissan coils with boot change

Supertec R35 Coil adaptor for RB26

RB26 single turbo with Audi coils from Almasi Tuning
IP R35 coils vs stock R35 coil output at various charge times

  • Audi coils
  • LS coils
    • GM/AC Delco D585 "LQ9" Coil Issues, Fixes, and Warranties
      • Early in the use of these coils Many of the ECU manufacturers were recommending dwell times of 5-6 MS. This seemed to work well but soon reports of blown engines began to appear, apparently with the LQ9 coils as the cause. It was found that when excessive dwell is used, the coils will sense a charge overcurrent and self discharge in advance of the ignition pulses's falling edge, effectively advancing the the spark to a dangerous and sometimes destructive degree. The fix for this is to limit dwell to 3.4 MS or less.
  • Mercury Marine
  • Honda CBR
  • Yaris Coils

Buy USA Legal R32 Skylines at! for Nissan Skyline GT-R and GT-R parts.

Buy USA legal JDM vehicles over 25 years old here

1 comment:

Unknown said...

I went to the audi r8 coil conversion. I sold my spitfire coils, wiring specialties harness and ignitor and purchase brand new audi coils and a harness made from a local in canada and ended up with money left over. Total cost was $430 cad for coils and harness. I had to cut the plug for the ignitor and wire in the new harness. Was easy to do with provided instuctions. I went this way simply to eliminate the ignitor and i dnt mind the look either. Also if a coil goes i can purchase 1 new coil unlike spitfire where you have to buy a set or gamble on a used one.
Downside to the r8 coil is they sit higher and you cannot use the coil cover anymore. I never ran the cover anyway as it is a heat trap.
Currently im using bcpr7es and pushing 660whp 29psi and have had no issues.