BMW M135i F20 on dyno at DC Remapping UK

Stage 1 · N55 3.0T · ECU Calibration

BMW M135i F20 Stage 1 Remap

3.0 turbo · 326PS · Rear-Wheel DriveCustom dyno ECU tuning for the BMW M135i F20. Proven gains to 401.7bhp and 682Nm on 99RON, developed in-house on our 4WD linked rolling road.

401.7bhpStage 1 · from 321.5

682NmTorque · from 484

+80.2bhpPower Increase · On 99RON fuel

Book Your Appointment See the dyno results

4WD linked dyno
S1 · Stage Level · No Hardware Mods
Before and after printout
Tuning BMWs for 14+ years

About This Tune

N55 3.0 Turbo. Proper Numbers.

The BMW M135i F20 is powered by the N55 3.0 turbo, one of the most capable and tuneable straight-six petrol engines ever built. From the factory it produces 326PS, but with a custom Stage 1 dyno calibration from DC Remapping, the real potential of this engine is unlocked.

We consistently achieve 401.7bhp and 682Nm on 99RON fuel, transforming the M135i from a quick car into a genuinely rapid one. Throttle response is sharpened significantly, the mid-range pulls harder and the power delivery across the entire rev range is much more linear and progressive.

All calibration is carried out live on our 4WD linked rolling road, every change tested and validated in real time. The result is a tune that feels factory integrated, not aggressive or harsh.

401.7bhp and 682Nm on 99RON, proven on our dyno
Sharpened throttle response and improved mid-range pull
No hardware modifications required
Full vehicle health check carried out before tuning
Before and after dyno printout included
Compatible with xHP ZF8 gearbox tuning

Figures vary depending on fuel quality. Results shown are on 99RON premium fuel. On 97RON you can expect slightly lower figures. We always recommend running 99RON for maximum performance and to get the most from your calibration.

Live Dyno Data

The Numbers Don't Lie.

BMW M135i F20 Dyno Chart — Stock vs Stage 1

Measurement	Stock	DC Stage 1
Engine Power	321.5 HP @ 5703 RPM	401.7 HP +80hp @ 5266 RPM
Engine Torque	484 Nm @ 2818 RPM	682 Nm +198nm @ 2766 RPM
Wheel Power	262.0 HP @ 5072 RPM	353.4 HP +91hp @ 5266 RPM

Power321.5401.7bhp+80.2 bhp · +25%

Torque484682Nm+198 Nm · +41%

Tested at DC Performance Centre, Warrington. Figures shown on 99RON premium fuel. Results on 97RON will differ slightly.

RON

Fuel Note
Figures shown are on 99RON premium unleaded. On 97RON you can expect slightly lower outputs. For best results always use 99RON on a tuned M135i.

Customer Reviews

What Our Customers Say.

What BMW owners say on Google

4.9 from 257+ Google reviews

★★★★★

Had my bmw 420i remapped and gearbox software on 29/08/25. Customer service was great, and any questions I asked they were more than happy to explain. Friendly atmosphere and good set up. The car feels totally different. …

Jamie Wilson · BMW 420i · Google review

★★★★★

Went in this morning to have a custom stage 1 on my G20 320i. Dan was very professional and welcoming when I came in, had it done within 2 hours and the results did not disappoint! I would highly recommend 📈

Adam Lamb · BMW 320i · Google review

★★★★★

What a great place to get your cars remapped dan is a lovely guy who welcomes you an tunes your car safely so happy with my bmw stage 1 388.9 bhp with xhp what a combo will be back for more in the future cheers again dan

Wezim Mirza · BMW · Google review

Quoted word for word from our Google reviews. Read them all on Google.

How It Works

The Process.

Health Check

Full diagnostic check before any tuning begins. Any issues are resolved before we start. We also check fuel grade used.

Baseline Run

Your M135i is strapped to our 4WD linked dyno for a baseline power run. Exact stock figures recorded before any changes are made.

Custom Calibration

A bespoke calibration is written and applied live on the dyno, developed specifically for your M135i and the fuel you are running.

Power Run & Printout

Final validation run completed. You leave with a full before and after dyno printout showing your exact power and torque gains.

FAQs

BMW M135i Tuning Questions

How much power will a Stage 1 remap add to my BMW M135i?

Our Stage 1 maps are custom-built on our in-house 4WD dyno and tailored to your exact BMW M135i, never a generic off-the-shelf file. You'll see a substantial, fully dyno-proven gain in both power and torque; the headline figures for this platform are shown at the top of this page. Because every map is refined over multiple runs, the results are realistic, repeatable and safe.

Is remapping my BMW M135i safe and reliable?

Yes. We tune strictly within the safe mechanical limits of your BMW M135i's engine and gearbox, monitoring temperatures, pressures and torque loads across multiple dyno pulls. We've spent 14+ years tuning these platforms, so our maps prioritise long-term reliability alongside performance.

Will a remap affect my warranty or insurance?

A remap is an aftermarket modification, so it's the owner's responsibility to declare it to their insurer. Our maps are fully reversible, we keep your original factory file and can return the BMW M135i to completely standard whenever you need, for example before a main-dealer visit.

Is the remap reversible?

Completely. Your original factory software is saved before we start, so your BMW M135i can be returned to stock at any time.

Will tuning improve my BMW M135i's fuel economy?

Many owners notice improved MPG, especially on a steady motorway cruise, because the engine makes its torque more efficiently and needs less throttle for the same progress. Driving style is the biggest factor, drive it the same and economy often improves; enjoy the extra performance and the savings will simply be smaller.

How long does it take, and do you tune on a dyno?

Most Stage 1 tunes are completed within a few hours; allow up to a day for combined ECU and gearbox work. Every BMW M135i is mapped on our in-house 4WD dyno in Warrington, never on the road, so the result is measured and consistent. You're welcome to relax in our customer waiting area while we work.

Check Your Vehicle

See What Your Car Will Make

Pick your make, model and engine for the expected Stage 1 and Stage 2 gains, your price, and book straight from the result.

Make Model Generation Engine

Choose your make to begin.

Ready to Unlock Your M135i F20?

Get a quote or book your Stage 1 appointment at DC Performance Centre, Warrington.

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