B58 Gen 2 · 3.0 single-turbo inline-six
The Gen 2 B58 is BMW's later 3.0-litre single-turbo straight-six — smoother, cleaner and with even more headroom than the engine that built its reputation. It powers the M340i, M440i, M240i (G42), Z4 M40i, X3/X4 M40i and the Toyota Supra 3.0.
B58 Gen 2 vehicles
SamuelTuned covers B58 Gen 2 tuning and remapping across the BMW M240i (G42) (G42), BMW M340i (G20 / G21), BMW M440i (G22 / G23 / G26), BMW Z4 M40i (G29), BMW X3 M40i (G01 / G45), BMW X4 M40i (G02) and Toyota Supra 3.0 (J29 / DB). Each one gets a custom, individually-calibrated remote ECU remap — Stage 1, Stage 2 and Stage 3. Open the configurator on your car to choose your stage, add the options that fit, and send the full build to Samuel.
G42
M240i
374 bhp stock
M240i Configure Tuning
G20 / G21
M340i
374 bhp stock
M340i Configure Tuning
G22 / G23 / G26
M440i
374 bhp stock
M440i Configure Tuning
G29
Z4 M40i
382 bhp stock
Z4 M40i Configure Tuning
G01 / G45
X3 M40i
374 bhp stock
X3 M40i Configure Tuning
G02
X4 M40i
374 bhp stock
X4 M40i Configure Tuning
J29 / DB
Supra 3.0
382 bhp stock
Supra 3.0 Configure Tuning
Engine guide
The B58 is widely regarded as one of the strongest stock bottom ends BMW has built. The Gen 2 adds a more modern DME and improved cooling, and it takes a custom tune extremely well — big, safe, repeatable gains with the stock turbo before you've touched the hardware. Stage 1 alone transforms the car.
An OTS map has to assume worst-case fuel and hardware. Samuel maps each B58 Gen 2 to your datalogs, your fuel and your supporting mods, so you get the full benefit safely. That matters most on E85 and on Supra builds, where fuelling and the gearbox calibration need to be matched to the car rather than a one-size file.
Stage 1 is software only. Stage 2 adds a downpipe and intake. E85 flex unlocks the biggest jump on pump-friendly hardware. From there the stock turbo eventually caps out and a hybrid/upgraded turbo opens the door to genuine 500+ bhp builds, fully calibrated around your setup.
Tune stages
Stage 1
~440–470 bhp
Software only on the stock turbo. Huge mid-range over standard.
Stage 2
~480–510 bhp
Downpipe + intake. More top-end and sustained boost.
E85 flex
520+ bhp
Flex-fuel kit + dedicated ethanol map for the biggest safe gains.
Hybrid turbo
Quoted per build
Upgraded turbo + supporting fuel. Bespoke calibration.
Figures are indicative and depend on the exact model, fuel and supporting hardware. Every tune is calibrated individually — open the configurator for your car for the precise build and price.
FAQ
A stock-turbo Stage 1 on the Gen 2 B58 typically lands around 440–470 bhp on quality pump fuel — a substantial step over the ~374 bhp standard figure, with no hardware required.
Yes. The A90 Supra runs the B58 Gen 2 and is tuned exactly like the BMW versions on Bootmod3 or MHD, with the ZF 8-speed tuned alongside on xHP.
The B58 has an exceptionally strong stock bottom end and responds very well to a properly calibrated tune. Samuel maps conservatively-but-effectively to your fuel and hardware so the car stays healthy.
Yes — the ZF 8-speed responds brilliantly to a custom xHP TCU tune for firmer, faster shifts and raised torque limits, which we can add alongside the engine map.
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