BMW 3 Series (E46) 1998-2005 323i 170bhp Stage 1 Eco remap figures
The Stage 1 Eco map for the BMW 3 Series 323i 170bhp (1998-2005): 185bhp and 269Nm expected from a standard 170bhp and 245Nm, up to +15bhp and +24Nm. It keeps most of the Stage 1 gain (Stage 1 is 190bhp and 271Nm) and is tuned with economy in mind: the choice if you want the performance and care what each tank costs.
Choose your map
Stage 1 Eco remap figures
Stage 1 Eco is performance with economy in mind. It keeps most of the Stage 1 gain, so the car still pulls well, but the map is shaped for efficient, relaxed driving rather than flat-out output. It is above the standard figures. We don't quote mpg, because economy depends on the car and how it is driven.
| Stock | Vanguard expected | Expected gain, up to | |
|---|---|---|---|
| Power | 170 bhp | 185 bhp | +15 bhp |
| Torque | 245 Nm | 269 Nm | +24 Nm |
All maps at a glance
| Map | Power | Torque | Expected gain, up to |
|---|---|---|---|
| Stock | 170 bhp | 245 Nm | |
| Stage 1Maximum software-only performance | 190 bhp | 271 Nm | +20 bhp +26 Nm |
| Stage 1 EcoPerformance with economy in mind | 185 bhp | 269 Nm | +15 bhp +24 Nm |
| Eco mapEconomy first | 183 bhp | 268 Nm | +13 bhp +23 Nm |
Who is the Stage 1 Eco map for?
- Naturally aspirated owners who want a little more response and a more efficient, relaxed drive. Every map we list stays above standard.
- Drivers who want the small gain on offer without chasing peak output.
- Anyone who would otherwise take the full Stage 1 map but wants it tuned with economy in mind.
How Stage 1 Eco compares with Stage 1
Full Stage 1 on this BMW 3 Series is expected to give 190bhp and 271Nm (+20bhp, +26Nm). The Stage 1 Eco keeps about 75% of that power gain and 92% of the torque gain, so you get 185bhp and 269Nm: 5bhp less and 2Nm less than Stage 1, with the map shaped for efficient, relaxed driving, so it suits you if you want the pull and care about running costs. Both sit above the standard 170bhp and 245Nm.
What this means for your 3 Series
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 MS41/42 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 Eco questions
How much power does the Stage 1 Eco map give the BMW 3 Series 323i 170bhp?
We expect 185bhp and 269Nm against 170bhp and 245Nm as standard: up to +15bhp and +24Nm. These are expected figures, and we confirm what is achievable on your own car after a diagnostic check.
How does Stage 1 Eco differ from Stage 1 on this engine?
Full Stage 1 is expected to give 190bhp and 271Nm. Stage 1 Eco gives 5bhp less and 2Nm less, in exchange for a map shaped with economy in mind. It still sits above the standard figures.
Is Stage 1 Eco or the Eco map better for me?
Choose Stage 1 Eco if you want the performance (185bhp and 269Nm) and still care about running costs. Choose the Eco map (183bhp and 268Nm) if economy matters more than pace.
Will the Stage 1 Eco map save fuel?
It is tuned with economy in mind while keeping most of the Stage 1 performance. We do not quote mpg figures, because economy depends on the car, its condition and how it is driven.
Do I need to tell my insurer about a remap?
Yes. A remap is a modification, so you should declare it to your insurer.
More BMW 3 Series figures
Other petrol variants
- 325i 192bhp 1998-2005
- 328i 193bhp 1998-2005
- 330i 231bhp 1998-2005
- M3 338bhp 2001-2006
- M3 CSL 360bhp 1998-2005
All petrol 3 Series (E46) variants · 3 Series (E46) 1998-2005 overview · All BMW figures