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The straight-six that made BMW tuning easy again. M340i, X3 M40i, Z4 M40i, Supra.
B58 Club is the deep engine club for BMW's most tunable modern motor: bootmod3 and MHD experience, intercooler and downpipe results, ZF8 tune behaviour, cooling in heat, and shared dyno data. The engine is the same wherever it was sold, so another owner's dyno sheet is worth reading.
For verified owners of any B58 car: M340i, M240i, X3 and X4 M40i, Z4 M40i, 740i, Supra.
What happens here: engine-platform deep dives (oil, coolant, carbon, turbo and gasket behaviour in heat), dyno days and tuner comparisons, club drives that mix badges around one engine, a parts cross-reference maintained by members, and shared long-term reliability logs.
No members yet. Applications are open.
Free on every membership. You apply with the car in your garage and a reviewer decides, usually within 48 hours.
Checked by hand. Documents are only seen by the reviewers, through links that expire in 15 minutes.
No approved members yet. The first application could be yours.