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S55 Spark Plugs Guide
The S55 runs an NGK 97506 spark plug from the factory. Below is comprehensive information on this plug and its upgrade/replacement alternatives.
S55 Spark Plug Specifications
| Plug Model | Heat Range | Pre-Ignition Protection | Projection | Position | Material | Compatible Coils | Default Gap |
|---|---|---|---|---|---|---|---|
| NGK 96987 (Discontinued - Replaced By 97506) | 8 | Standard | Extended | 0 | Iridium | OEM & PR | 0.8mm / 0.031" |
| NGK SILZKBR8C8S (Discontinued - Replaced By SILZKBR8F8S) | 8 | Improved | Standard | 0 | Iridium | OEM & PR | 0.8mm / 0.031" |
| NGK SILZKBR8F8S (Only Available From BMW Germany or Brazil as 12120042724) | 8 | Improved | Standard | 0 | Iridium | OEM & PR | 0.75mm / 0.030" |
| NGK 97506 | 8 | Standard | Extended | 0 | Iridium | OEM & PR | 0.8mm / 0.031" |
| NGK 91784 | 8 | Improved | Standard | -2.75mm / -0.108" (Sits further from piston) | Ruthenium | OEM & PR | 0.8mm / 0.031" |
| BRISK 2MOR10S | 9 | Enhanced | Standard | -3.6mm / -0.142" (Sits further from piston) | Silver | OEM & PR | 0.4mm / 0.016" |
| NGK 94201 | 8 | Improved | Standard | -1.6mm / -0.063" (Sits further from piston) | Iridium | Bxx / N63T3 Coil Upgrade ONLY | 0.75mm / 0.030" |
| NGK 93560 | 9 | Improved | Standard | -3.1mm / -0.122" (Sits further from piston) | Iridium | Bxx / N63T3 Coil Upgrade ONLY | 0.7mm / 0.028" |
| BRISK 2MOER12YS | 8 | Improved | Standard | -2.75mm / -0.108" (Sits further from piston) | Silver | Bxx / N63T3 Coil Upgrade ONLY | 0.5mm / 0.020" |
| BRISK 2MOER10S | 9 | Enhanced | Standard | -3.6mm / -0.142" (Sits further from piston) | Silver | Bxx / N63T3 Coil Upgrade ONLY | 0.4mm / 0.016" |
Pre-Ignition / Detonation Protection Explained
- Standard: What was considered standard from the OEM
- Improved: This is considered an improvement over the standard by way in which the Metal Shell has been extended to cover/shield more of the electrode (positive firing end) ceramic but does not shield/protect all of the ceramic
- Enhanced: This is when the metal shell extension completely covers/shields the electrodes ceramic and provides the most pre-ignition or detonation protection for the ceramic
Why Projection Type Matters
Projection is how far from the body/shell of the plug the ground strap and conversely electrode extend. The longer or further away from the plug body they are the better spark efficiency but the greater risk of plug failure or potential engine damage from a hot ground strap causing pre-ignition.
Factors That Can Reduce Plug Life
- Gapping Plugs: Gapping a plug can reduce its life as the precious metals on the electrode and ground strap can wear out quicker.
- Incorrect Heat Range: Running High Boost Pressures or High Octane Fuels can also lead to a premature failure or reduced service life of the plug.
- Detonation / Pre-Ignition: This can cause the ceramic in the plug to prematurely crack and end up becoming dislodged, this usually results in engine failure / piston damage.
Plug Recommendations by Application
| Plug Model | Ideal Max Service Life | Max Ideal Boost | Reasoning |
|---|---|---|---|
| NGK 96987 (Discontinued) | 25,000 KM (15,500 mi) @ 0.56mm/0.022" Gap | OEM Gap 50,000 KM (31,000 mi) | 26 PSI / 1.79 bar @ Sea Level | Extended Projection can lead to causes of pre-ignition in highly boosted applications or race environments followed by plug heat range limitations in the ceramic surviving long highly abusing loads |
| NGK SILZKBR8C8S (Discontinued) | 25,000 KM (15,500 mi) @ 0.56mm/0.022" Gap | OEM Gap 50,000 KM (31,000 mi) | 30 PSI / 2.07 bar @ Sea Level | Heat range limitations in the ceramic surviving long highly abusing loads |
| NGK SILZKBR8F8S | 25,000 KM (15,500 mi) @ 0.56mm/0.022" Gap | OEM Gap 50,000 KM (31,000 mi) | 30 PSI / 2.07 bar @ Sea Level | Heat range limitations in the ceramic surviving long highly abusing loads |
| NGK 97506 | 25,000 KM (15,500 mi) @ 0.56mm/0.022" Gap | OEM Gap 50,000 KM (31,000 mi) | 26 PSI / 1.79 bar @ Sea Level | Extended Projection can lead to causes of pre-ignition in highly boosted applications or race environments followed by plug heat range limitations in the ceramic surviving long highly abusing loads |
| NGK 91784 | 12,000 KM (7,500 mi) @ 0.56mm/0.022" Gap | OEM Gap 25,000 KM (15,500 mi) | 30 PSI / 2.07 bar @ Sea Level | Heat range limitations in the ceramic surviving long highly abusing loads |
| BRISK 2MOR10S | OEM Gap 10,000 KM (6,200 mi) | 40 PSI / 2.76 bar @ Sea Level | Heat range limitations in the ceramic surviving long highly abusing loads |
| NGK 94201 | 25,000 KM (15,500 mi) @ 0.56mm/0.022" Gap | OEM Gap 50,000 KM (31,000 mi) | 30 PSI / 2.07 bar @ Sea Level | Heat range limitations in the ceramic surviving long highly abusing loads |
| NGK 93560 | 25,000 KM (15,500 mi) @ 0.56mm/0.022" Gap | OEM Gap 50,000 KM (31,000 mi) | 40 PSI / 2.76 bar @ Sea Level | Heat range limitations in the ceramic surviving long highly abusing loads |
| BRISK 2MOER12YS | OEM Gap 15,000 KM (9,300 mi) | 30 PSI / 2.07 bar @ Sea Level | Heat range limitations in the ceramic surviving long highly abusing loads |
| BRISK 2MOER10S | OEM Gap 10,000 KM (6,200 mi) | 40 PSI / 2.76 bar @ Sea Level | Heat range limitations in the ceramic surviving long highly abusing loads |