N55 · 3.0 single-turbo inline-six

BMW N55 tuning

The N55 is the single-turbo 3.0-litre straight-six that came before the B58 — the engine in the F87 M2, 335i, 435i, M135i, M235i, 535i, X3 35i and Z4 35i. It is still a hugely rewarding and cost-effective car to tune.

See the N55 chassis

N55 vehicles

BMW N55 tuning, by model

SamuelTuned covers N55 tuning and remapping across the BMW M2 (N55) (F87 pre-LCI), BMW M235i (F22), BMW M135i (F20 / F21), BMW 135i (E82 / E88), BMW 335i (F30 / F31), BMW 335i (E90) (E90 / E92 / E93), BMW 435i (F32 / F33 / F36), BMW 535i (F10 / F11), BMW X3 35i (F25) and BMW Z4 35i (E89). 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.

F87 pre-LCI

M2 (N55)

365 bhp stock

M2 (N55) Configure Tuning

F22

M235i

322 bhp stock

M235i Configure Tuning

F20 / F21

M135i

322 bhp stock

M135i Configure Tuning

E82 / E88

135i

302 bhp stock

135i Configure Tuning

F30 / F31

335i

302 bhp stock

335i Configure Tuning

E90 / E92 / E93

335i (E90)

302 bhp stock

335i (E90) Configure Tuning

F32 / F33 / F36

435i

302 bhp stock

435i Configure Tuning

F10 / F11

535i

302 bhp stock

535i Configure Tuning

F25

X3 35i

302 bhp stock

X3 35i Configure Tuning

E89

Z4 35i

302 bhp stock

Z4 35i Configure Tuning

Engine guide

BMW N55 tuning explained

The B58 precursor — still a brilliant tune

The N55 set the template the B58 perfected, and it responds strongly to a custom map. Stage 1 frees up meaningful boost and timing the factory left conservative, and on a well-sorted N55 the mid-range gain is immediately obvious. These cars offer a lot of performance per pound spent.

Custom on an older platform

Most N55 cars now have age and miles, and condition varies. Calibrating to your datalogs and fuel — rather than a generic file — is the safe way to get the full gain on a used engine, and lets Samuel work around the realities of your specific car.

Stages and E85

Stage 1 is software only. Stage 2 adds a downpipe and intake. E85 flex gives the biggest jump on the stock turbo, and from there an upgraded turbo opens up bigger builds with a bespoke map.

Tune stages

N55 tuning stages: Stage 1, Stage 2 & Stage 3

Stage 1

~360–390 bhp

Software only on the stock turbo. Strong mid-range gain.

Stage 2

~390–420 bhp

Downpipe + intake for fuller delivery.

E85 flex

420+ bhp

Flex-fuel kit + ethanol map for the biggest stock-turbo gain.

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

N55 tuning, common questions

Yes — the N55 responds very well to a custom map and the cars are now affordable, making it one of the best value six-cylinder tunes we offer. Stage 1 alone is a clear step up.

A custom Stage 1 on the N55 typically lands around 360–390 bhp on pump fuel, with E85 going further. Exact figures depend on the car, fuel and hardware.

Bootmod3 and MHD both cover the N55. The tune is delivered remotely to flash at home.

When calibrated to your datalogs and fuel, yes. A bespoke map is specifically the right approach on an older engine where a generic file can be risky.

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