BMW Z4 (E85 E86) 2002-2008 2.5i 174bhp remap figures
Thinking of remapping a BMW Z4 2.5i 174bhp? The standard car makes 174bhp and 231Nm; with a Stage 1 remap from our Leicester workshop we expect around 195bhp and 257Nm, up to +21bhp and +26Nm.
Choose your map
Stage 1 remap figures
A Stage 1 remap is a software-only change to the ECU on an otherwise standard car. It needs no extra parts, which makes it the usual starting point.
| Stock | Vanguard expected | Expected gain, up to | |
|---|---|---|---|
| Power | 174 bhp | 195 bhp | +21 bhp |
| Torque | 231 Nm | 257 Nm | +26 Nm |
All maps at a glance
| Map | Power | Torque | Expected gain, up to |
|---|---|---|---|
| Stock | 174 bhp | 231 Nm | |
| Stage 1Maximum software-only performance | 195 bhp | 257 Nm | +21 bhp +26 Nm |
| Stage 1 EcoPerformance with economy in mind | 190 bhp | 255 Nm | +16 bhp +24 Nm |
| Eco mapEconomy first | 188 bhp | 254 Nm | +14 bhp +23 Nm |
Who is the Stage 1 map for?
- Drivers who want a sharper throttle and a small, honest gain from software alone.
- Owners who would rather keep the car standard in every other way.
- Anyone who wants the fullest software-only map for this engine, accepting that the gain is modest without a turbocharger.
What this means for your Z4
Naturally aspirated petrol engines have no boost to raise, so gains from software alone are more modest than on a turbocharged car and come from fuelling, ignition and throttle response.
Engine management is by a Siemens MSV70 unit. Older engine management is simpler to work with, but age matters: worn sensors, leaks and tired components can hold back what a remap delivers, which is why we run a diagnostic check first.
We remap at our Belgrave Gate workshop in Leicester, or at your home or work within 30 miles, and every job starts with a diagnostic check.
Please note: these are expected figures, not guarantees. Real results vary with the condition of the vehicle, the ECU software version, fuel quality and the hardware fitted. Some options - including Stage 2 and anything that needs extra hardware - are for off-road or competition use only. We check every vehicle first and confirm what is achievable before any work starts.
Figures reviewed 22 October 2026.
Stage 1 questions
How much power does the Stage 1 map give the BMW Z4 2.5i 174bhp?
We expect 195bhp and 257Nm against 174bhp and 231Nm as standard: up to +21bhp and +26Nm. These are expected figures, and we confirm what is achievable on your own car after a diagnostic check.
Does a Stage 1 remap need any extra parts on the BMW Z4 2.5i 174bhp?
No. Stage 1 is a software-only change to the ECU on an otherwise standard car.
Is there a gentler map than Stage 1 for this engine?
Yes, two. Stage 1 Eco is performance with economy in mind: 190bhp and 255Nm expected. The Eco map is economy first: 188bhp and 254Nm. Both still sit above the standard 174bhp and 231Nm.
Do I need to tell my insurer about a remap?
Yes. A remap is a modification, so you should declare it to your insurer.