Ignition Coil + Iridium Spark Plugs for Mercedes Benz SL-Class (2013-2017) 4.7L 5.5L

OEM-Spec Direct-Fit Ignition Coil & Iridium Spark Plug Kit for 2013-2017 Mercedes Benz SL-Class 4.7L, 5.5L (R231 M278 / M157)

What it Does: The complete ignition kit replaces degraded factory coil-on-plug packs and spark plugs on the 2013-2017 Mercedes Benz SL-Class to eliminate high-load misfires, stabilize idle, and restore peak combustion efficiency.

The Stock Mercedes Benz SL-Class Ignition Breakdown Under Boost

Twin-turbocharged Mercedes-Benz direct-injected powerplants generate intense thermal loads inside the cylinder heads. Over time, the factory coil packs on the M278 4.7L and M157 5.5L suffer epoxy insulation breakdown and internal dielectric puncture due to continuous heat cycles. Concurrently, factory fine-wire electrodes suffer gap erosion from sustained high boost pressure. This combined degradation leads to spark blow-out at wide-open throttle, micro-arcing, intermittent P0300 through P0308 diagnostic trouble codes, and sluggish transient response under heavy load.

The Engineering Solution

This ignition refresh kit pairs eight high-output coil-on-plug modules with factory-spec double-iridium spark plugs to restore factory secondary-circuit voltage. The ignition coils utilize high-grade magnetic silicon steel cores paired with vacuum-encapsulated copper windings to resist insulation failure up to elevated under-hood operating temperatures. The included Bosch ZR6SII3320 double iridium plugs feature laser-welded fine-wire center electrodes and iridium-tipped ground electrodes, providing exceptional spark stability, reduced arc-voltage requirements, and resistance to direct-injection carbon fouling.

Technical Specifications

Compatibility

• 2013-2017 Mercedes Benz SL-Class SL550 4.7L V8 Biturbo (M278)
• 2013-2017 Mercedes Benz SL-Class SL63 AMG 5.5L V8 Biturbo (M157)

Frequently Asked Questions

Does this fit the R231 SL-Class?
Yes, this is a direct fit for the 2013-2017 Mercedes Benz SL-Class equipped with the M278 4.7L or M157 5.5L biturbo engines.

Do the spark plugs require gapping prior to installation?
No, these double iridium spark plugs arrive pre-gapped to factory specifications; do not mechanically gap fine-wire electrodes as ceramic or iridium alloy damage can occur.

The Mercedes Benz Precision Standard

Engineered to meet stringent European direct-injection requirements, these components maintain precise primary and secondary resistance values to preserve ECU monitoring integrity and guarantee misfire-free operation without triggering false check engine lights.