Vauxhall Astra (G) 1998-2004 1.8 16v 123bhp Stage 1 Eco remap figures
The Stage 1 Eco map for the Vauxhall Astra 1.8 16v 123bhp (1998-2004): 134bhp and 184Nm expected from a standard 123bhp and 170Nm, up to +11bhp and +14Nm. It keeps most of the Stage 1 gain (Stage 1 is 137bhp and 185Nm) 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 | 123 bhp | 134 bhp | +11 bhp |
| Torque | 170 Nm | 184 Nm | +14 Nm |
All maps at a glance
| Map | Power | Torque | Expected gain, up to |
|---|---|---|---|
| Stock | 123 bhp | 170 Nm | |
| Stage 1Maximum software-only performance | 137 bhp | 185 Nm | +14 bhp +15 Nm |
| Stage 1 EcoPerformance with economy in mind | 134 bhp | 184 Nm | +11 bhp +14 Nm |
| Eco mapEconomy first | 132 bhp | 183 Nm | +9 bhp +13 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 Vauxhall Astra is expected to give 137bhp and 185Nm (+14bhp, +15Nm). The Stage 1 Eco keeps about 79% of that power gain and 93% of the torque gain, so you get 134bhp and 184Nm: 3bhp less and 1Nm 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 123bhp and 170Nm.
What this means for your Astra
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.
This car is listed with a Siemens Simtec 71 engine control 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 Vauxhall Astra 1.8 16v 123bhp?
We expect 134bhp and 184Nm against 123bhp and 170Nm as standard: up to +11bhp and +14Nm. 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 137bhp and 185Nm. Stage 1 Eco gives 3bhp less and 1Nm 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 (134bhp and 184Nm) and still care about running costs. Choose the Eco map (132bhp and 183Nm) 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.