NGK 93253 R2556G-9 Racing Spark Plug Iridium Heat Range 9

Vehicle Fitment

• No confirmed vehicle applications - NGK's own official product page states no automotive or powersports applications are associated with this part number

Fitment Notes

• One retailer listing mentions this plug being used on modified Mitsubishi Lancer Evolution builds, but this appears to be a seller's own recommendation rather than confirmed OE or cross-reference fitment - verify compatibility using the specs below before purchasing
• Verify exact engine compatibility using the plug's thread size, reach, gap, and heat range against your engine's specification, or by cross-referencing your OE/competitor racing plug part number

Features

• Fine-wire iridium center electrode improves sparking and ignitability under extreme racing conditions
• Platinum-tipped ground electrode in a slant, pin-type configuration further enhances ignitability and durability
• Special insulator nose configuration improves throttle response
• Corrugated ribs help prevent flashover
• Pure alumina silicate ceramic insulator provides superior strength and better heat transfer
• Copper core aids heat removal under sustained high-load conditions
• Triple seals prevent leakage
• Engineered to withstand the severe mechanical and thermal shock of high-revving, high-compression race engines

Specifications

• NGK stock number: 93253
• Service number: R2556G-9
• Center electrode material: Copper core, iridium tip, fine wire
• Ground electrode: Platinum, slant configuration, pin type, 1 ground electrode
• Thread diameter: 12mm
• Hex size: 5/8 in.
• Reach: 26.5mm
• Insulator height: 51.00mm
• Heat range: 9 (cold, racing-oriented)
• Gap: 0.028 in.
• Resistance: Approx. 5,000 ohm
• Seat type: Flat
• Torque spec: 10.8-18 lb-ft (cast iron), 10.8-14.5 lb-ft (aluminum)

Included Components

• 1x Spark Plug

Product Description

The NGK 93253 (R2556G-9) is a purpose-built racing spark plug from NGK's Racing Series, engineered specifically to withstand the severe mechanical and thermal shock of high-revving, high-compression race engines. Its fine-wire iridium center electrode is paired with a platinum-tipped ground electrode in a slant, pin-type configuration - both materials chosen for their durability and lower voltage requirements under sustained race conditions.

A specially configured insulator nose is designed to improve throttle response, while corrugated ribs and triple seals guard against flashover and leakage respectively. The pure alumina silicate ceramic insulator and copper core work together to manage the extreme heat generated in a race engine, helping the plug hold up where a standard street plug would fail.

Because this is a specialized racing plug with no manufacturer-confirmed vehicle application, fitment depends entirely on matching its thread size (12mm), reach (26.5mm), gap (0.028 in.), and heat range (9) to your specific race engine's requirements - this is not a plug to select by vehicle name, but by engine specification and tuning needs. Consult your engine builder or tuner to confirm this heat range and configuration is correct for your combination before installing.