Supertech BMW B58 Beehive Valve Spring Kit
Supertech SPRK-MCB58 – Beehive Valve Spring Kit (BMW B58)
Key Features
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Complete kit of 24 beehive springs purpose-built for the 3.0 L BMW B58 engine found in the latest 340i, 440i, M240i, Z4 M40i and Toyota GR Supra.
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Seat pressure 75 lbs @ 37 mm and open pressure 155 lbs @ 10 mm lift—ample margin for aggressive cam profiles and high boost.
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Maximum lift 12.2 mm with a coil-bind height of 23.20 mm, ensuring compatibility with popular performance camshafts.
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Tapered beehive shape lowers moving mass and raises the natural frequency of the spring, suppressing valve-train resonance beyond 7 000 RPM.
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Includes your choice of steel (TE) or titanium (TI) retainers plus hardened steel spring seats for precise location and reduced rotating weight.
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Crafted from premium chrome-silicon alloy—heat-treated and shot-peened for exceptional fatigue life under sustained track conditions.
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Direct drop-in with OEM guides and Supertech or factory valves; no cylinder-head machining required.
Technical Specifications
| Parameter | Value |
|---|---|
| Springs in kit | 24 |
| Seat pressure | 75 lbs @ 37 mm install height |
| Open pressure | 155 lbs @ 10 mm lift |
| Spring rate | ≈ 8 lbs/mm |
| Maximum lift | 12.2 mm |
| Coil-bind height | 23.20 mm |
| OD (bottom / top) | 24.4 mm / 21.0 mm |
| ID (bottom / top) | 17.6 mm / 14.2 mm |
| Included hardware | 24 springs, 24 retainers (TE or TI), 24 seat locators |
Applications
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BMW B58 engines: F- & G-series 340i, 440i, M240i, Z4 M40i
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Toyota GR Supra 3.0 (A90/A91)
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Builds targeting >7 500 RPM, high-boost forced induction, or extended track-day abuse.
Benefits
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Eliminates valve float—maintains full cam control at elevated RPM and boost levels.
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Improves throttle response—lighter retainers reduce reciprocating mass.
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Future-proof—headroom for even more aggressive cams or additional boost down the road.
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Track-ready durability—alloy selection and heat treatment resist thermal fatigue during long sessions.