Starting in 2018 (US market) the Honda Accord was released with 2 new Turbo engine options. The K20c4 and the L15b. Both these Honda engines are direct injection and turbocharged making them extremely efficient while producing GREAT power with only a few basic mods and ECU tuning. Whether you have a bone stock Accord with the L15b or a modified/tuned Accord with the K20c4 ensuring you are using the correct spark plugs is key to making reliable power. In a rush to get your new spark plugs? No need to read any further here is the link to the exact NGK Iridium laser spark plugs needed for the 1.5 turbo or 2.0 turbo Accord 2018+ NGK ILZKAR8H8S
For those with the L15B 1.5L Turbo Accord (pictured above) or the K20c4 turbo engine (pictured below), we always recommend NGK Laser Iridium spark plugs. The exact part number needed for either engine is NGK ILZKAR8H8S and we keep these plugs in stock ready to ship! This is the exact spark plug to use in your L15b or K20c whether you have a stock car or a 600HP race car these are the plugs to use.
The NGK iridium spark plugs come pre-gapped to 0.030″ which is perfect for the turbo L15B or K20c engine. If you experience spark blow out with a fresh set of spark plugs gapped to 0.030″ its a sign your ignition coils have reached their limitations and using a larger coil for a hotter/more powerful spark is needed. (this in normally only on cars running 28psi and above). You may also apply a tiny dot of anti-seize on the threads of your plugs (very small amount) and dielectric grease in the boot of the ignition coil before installing the coils onto the plugs. The dielectric grease makes for easy removal of the ignition coil next time and helps prevent the coil boot from getting damaged/torn.
Fixing spark blow out:
If you don’t remember the last time you changed your spark plugs start with a fresh pair of plugs as that is cause of spark blow out 90% of the time. Stock car or modified you need to ensure your spark plugs are in good condition or engine performance will suffer badly. Any high power Turbo Accord with the L15b or K20c series engine makes its power through high cylinder pressures and great airflow through the cylinder head. The high cylinder pressures put the spark plug and ignition coil to the test. As spark plugs age and wear out the resistance increases this increased resistance combined with high cylinder pressures results in “spark blow out”. Spark blow out is a situation where the spark fails to arc from the spark plug’s electrode to the grounding strap causing a misfire and loss of power. Running NGK iridium plugs helps to ensure your engine will not suffer from spark blow out even under high boost high cylinder pressure situations. NGK iridium plugs have proven to last longer and perform better than any other spark plug option on the market both on and off the race track.
OEM Honda L15b & K20c Spark Plug Gap specs:
-L15B 1.5T Si Plug gap (factory setting) 0.70－0.75 mm (0.0276－0.0295″) **the SI runs higher boost than non SI l15b from the factory which is why they use a slightly smaller plug gap.
-L15B 1.5T Non-Si Plug gap (factory setting) 0.7－0.8 mm (0.028－0.031″)
-K20C1 & K20C4 Plug gap (factory setting) 0.7－0.8 mm (0.028－0.031″)
-Torque Specs for Aluminum cylinder head: 10.8-14.5 lb. ft.
-For high boost applications you may gap your spark plugs down as tight as 0.5mm If you are still experiencing spark blow out at this tight of a gap you will need to upgrade your ignition coils.