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Stainless Steel Black Nitride Exhaust Valves

 
Stainless Steel Black Nitride Exhaust Valves
Engine
BMW
    S54B32
    • B38B15
    • B48
    • B58B30
    • M20
    • M20 B25
    • M42
    • M50
    • M52
    • M54
    • M70
    • N53
    • N54 Turbo
    • N55
    • N55 Turbo
    • S14
    • S38
    • S42
    • S50
    • S50B30 Euro Version
    • S50B32 Euro Version
    • S52
    • S54B32
    • S55 Turbo
    • S63B44
    • S65 V8
    • S85 V10
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    Valve Set

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    • Each
    • Set of 12
    Supertech valve details – stem, head and tip close-ups

    Stainless Steel Black Nitride Exhaust Valves

    Supertech Stainless Steel Black Nitride (BN) Exhaust Valves combine the strength of EV8/21-4N stainless with a low-friction, wear-resistant surface. The result is reliable sealing, smoother operation, and long service life for street performance, track days, and moderate boost applications.

    • EV8 stainless base with BN surface for durability
    • Hardened tips, controlled stems, and swirl-polished heads
    • OE and oversize options (by application)

    Key Benefits

    Why Choose Stainless + BN

    • EV8 stainless base material for hot hardness and durability.
    • Black Nitride surface helps reduce friction and scuffing.
    • Improved wear and corrosion resistance for daily use and track days.
    • Controlled stem finish and hardened tips to extend guide and follower life.
    • Offered in OE diameter and oversize options where supported.

    Materials and Surface Finish

    Stainless EV8 (21-4N)

    High strength at temperature with consistent seat-face accuracy and stem concentricity.

    • Excellent fatigue resistance for long service life.
    • Stable performance in street and track-day duty.

    Black Nitride (BN) Finish

    A hard, low-friction surface treatment that promotes smoother motion and wear resistance.

    • Helps reduce guide and seat wear.
    • Dark appearance for quick identification.

    Surface Details

    • Swirl-polished heads for smoother boundary layer.
    • Controlled stem finish for consistent clearances.
    • Hardened tips for follower and lash component life.

    Engineering Options

    Geometry

    • Flat, dished, and tulip head shapes by application.
    • Undercut or straight stems as validated.

    Sizes

    • OE diameter for stock ports and chambers.
    • Oversize options for ported heads where supported.

    Compatibility

    • Match with Supertech springs and retainers for your cam profile.
    • Works with performance guides and seat materials.

    Use Cases

    Street and NA

    Stainless + BN offers excellent durability and smooth operation for daily-driven and naturally aspirated builds.

    Moderate Boost

    Suitable for moderate turbo and supercharged applications. For sustained high EGT or endurance racing, consider Inconel exhaust valves.

    Installation Notes

    • Measure guide ID and set stem-to-guide clearance by material.
    • Cut seats to proper angles and contact width; verify concentricity.
    • Check installed height, seat pressure, coil bind, and retainer-to-seal clearance.
    • Verify piston-to-valve clearance at intended lift and timing.
    • Follow appropriate break-in and inspection intervals for your application.

    FAQ

    How does Black Nitride compare to Inconel?

    BN is a surface treatment that improves wear and reduces friction on stainless valves. Inconel is a high-temperature alloy. For the highest EGT and endurance racing, Inconel is recommended.

    Does BN change valve dimensions?

    BN is a thin surface layer. Always verify stem-to-guide clearance during assembly to ensure proper fit.

    Can I re-coat or refinish BN valves?

    Consult your machine shop and Supertech support for guidance. Do not remove material that affects stem finish or seat geometry.

    Do I need upgraded springs?

    Use springs matched to your cam profile and valve mass. Proper seat and open pressures control valve motion at RPM.

    Shop Inconel Exhaust Valves Shop Valve Springs Guides and Seats

    Supported Applications

    Make Engines
    Acura B16A, B17A, B18A, B18B, B18C1, B18C5, D16A1 DOHC, J30, J32, J35 -SOHC VTEC, K20A2, K20A3, K24A2, K24Z7 DOHC VTEC, NSX C32B
    Alfa Romeo 155 Q4
    ASTON MARTIN Duratec 3.0L
    Audi 1.8T, 2.5T FSI, 2.7T, AEB, APB, BHF, BHK, EA113, EA888, R8 V10, R8 V8, TFSI
    BMW B38B15, B48, B58B30, M20 B25, M42, M50, M52, M54, N53, N54 Turbo, N55 Turbo, S14, S38, S42, S50, S50B30 Euro Version, S50B32 Euro Version, S52, S54B32, S55 Turbo, S63B44, S65 V8, S85 V10
    Citroen 175, THP150
    Ferrari 250 V12, 275 V12, 328 V8, 355 V8, 360 V8
    Fiat 500
    Ford Coyote 5.0 Gen 2, Coyote 5.0 Gen 3, Duratec 2.0, Duratec 2.3, Duratec 2.5, Duratec 3.0, Ecoboost 6cyl 3.5, Ecoboost DI 1.6, Ecoboost DI 2.0, Ecoboost DI 2.3, MK 2.5RS, Zetec DOHC
    GM Ecotec LEH-X20XEV, Ecotec LSJ, Ecotec Z20LET
    Honda B16A, B17A, B20, CR-Z, D15B, D16A6, D16A9 DOHC, D16Y6, D16Y7, D16Y8, D16Z6, D17A, F20C, F22A/B, F22C, H22A VTEC, H23A DOHC Non-VTEC, J30, J32, J35 -SOHC VTEC, K20A2, K20A3, K20A4, K20C1, K20Z1, K20Z3, K24A2, K24Z1, K24Z3, K24Z7 DOHC VTEC, L15A, LEA, R18A SOHC I-VTEC, ZC DOHC
    Hyundai G4KF, Theta L4
    Lamborghini 5.0 / 5.2 V10
    Lancia Delta
    Mazda 1.8 Miata BP, 626, B6 DOHC Miata, MX6, MZR 2.0, MZR 2.3, MZR 2.5, MZR Turbo, Probe, Protege
    Mini B38, B48, R53, R56 N14 JCW, R56 N14 S, R56 N18 JCW, R56 N18 S
    Mitsubishi 420A, 4B11 DOHC Turbo, 4G63, 6G72 DOHC
    Nissan 280Z, CA18 DET, HR15DE, KA24DE DOHC, RB20 DOHC Hydraulic Lifter, RB20 DOHC Solid Lifter Conversion, RB25 DOHC Hydraulic Lifter, RB25 DOHC NEO (solid lifter), RB25 DOHC Solid Lifter Conversion, RB26 DOHC, RNN14, SR20 VE P11 DOHC, SR20DE, SR20DET, TB48, VG30D DOHC, VK56DE, VQ35DE, VQ35DET, VQ37VHR, VR30DETT, VR38DETT
    Opel A18XER, C20LET, C20XE, LEH-X20XEV, Z16, Z18LER, Z20LET
    Peugeot EP6, EW10J4, EW10J4S, Group A, Prince, Prince EP6, TU5J4, TU5JP4, XU10J4, XU10J4S
    Renault F4R RS, F4RT 2.0LTS, F7R Clio Williams
    Subaru EG33 H6, EJ20 Turbo DOHC, EJ25 Non Turbo DOHC, EJ25 Non Turbo SOHC, EJ25 Turbo DOHC, EZ30 H6 (1st Gen), EZ30 H6 (2nd Gen), FA20, FA20F (DIT)
    Toyota 1FZ-FE I6, 1GR-FE Bucket version, 1JZ-GTE, 1ZZ-FE, 2AZ-FE, 2GR-FE, 2JZ-GE, 2JZ-GTE DOHC, 2RZ-FE, 2TR-FE, 2UZ-FE, 2ZZ-GE, 3RZ-FE, 3SGTE, 3UR-FE V8, 3UZ-FE V8, 4AGE 16V, 4AGE 20V, 5VZ-FE DOHC, 7MGTE, B58B30, FR-S 4U-GSE, G16E-GR
    Vauxhall C20LET, C20XE, C20XE, LEH-X20XEV, Z16, Z18LER, Z20LET
    VW 1.8lts, 1.8T, 2.2lt 5Cyl, 2.5T FSI, 2.7T, 5cyl., ABF, AEB, APB, DAZA, EA113, EA888, KR7A-9A, R32 VR6, TFSI, TTRS-RS3, VR6