5.0 · 240+ reviews
★ 5.0 on Google · 240+ 5-star reviews · 10,000+ vehicles tuned · 14+ years experience · In-house 4WD dyno · 0% finance available · BMW & VAG specialists · Warrington · ★ 5.0 on Google · 240+ 5-star reviews · 10,000+ vehicles tuned · 14+ years experience · In-house 4WD dyno · 0% finance available · BMW & VAG specialists · Warrington ·
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BMW M135i F20 on dyno at DC Remapping UK
Stage 1 · N55 3.0T · ECU Calibration

BMW
M135i F20

3.0 turbo · 326PS · Rear-Wheel Drive

Custom dyno ECU tuning for the BMW M135i F20. Proven gains to 401bhp and 682Nm on 99RON — developed in-house on our 4WD linked rolling road.

Book Your Appointment
+73hp
Power Increase
315 to 388 HP
+130nm
Torque Increase
418 to 682 Nm
388hp
Stage 1 Output
On 99RON fuel
S1
Stage Level
No Hardware Mods
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 401bhp 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.

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.

  • 401bhp 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
BMW M135i F20 wheel on dyno BMW M135i F20 rear on dyno
Live Dyno Data

The Numbers
Don't Lie.

BMW M135i F20 Dyno Chart — Stock vs Stage 1

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

Measurement Stock DC Stage 1
Engine Power 315.0 HP
@ 6144 RPM		 388.0 HP +73hp
@ 6309 RPM
Engine Torque 418 Nm
@ 2736 RPM		 682 Nm +130nm
@ 3005 RPM
Wheel Power 246.7 HP
@ 5954 RPM		 323.4 HP +77hp
@ 6227 RPM
Engine Power 315 to 388 HP
Engine Torque 418 to 682 Nm
Wheel Power 247 to 323 HP
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.

★★★★★

"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. Absolutely transformed the car."

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 car remapped. Dan is a lovely guy who welcomes you and tunes your car safely. So happy with my BMW stage 1 — 388.9bhp with xHP, what a combo. Will be back for more in the future."

Wezim Mirza BMW · Google review
How It Works

The Process.

01
Health Check
Full diagnostic check before any tuning begins. Any issues are resolved before we start. We also check fuel grade used.
02
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.
03
Custom Calibration
A bespoke calibration is written and applied live on the dyno, developed specifically for your M135i and the fuel you are running.
04
Power Run & Printout
Final validation run completed. You leave with a full before and after dyno printout showing your exact power and torque gains.

Ready to Unlock
Your M135i F20?

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

Get a Quote Book Online

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.