Jaguar XK (X150) 2006> 4.2 V8 R 420bhp Stage 1 Eco remap figures
The Stage 1 Eco map for the Jaguar XK 4.2 V8 R 420bhp (2006>): 446bhp and 602Nm expected from a standard 420bhp and 560Nm, up to +26bhp and +42Nm. It keeps most of the Stage 1 gain (Stage 1 is 455bhp and 606Nm) 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 | 420 bhp | 446 bhp | +26 bhp |
| Torque | 560 Nm | 602 Nm | +42 Nm |
All maps at a glance
| Map | Power | Torque | Expected gain, up to |
|---|---|---|---|
| Stock | 420 bhp | 560 Nm | |
| Stage 1Maximum software-only performance | 455 bhp | 606 Nm | +35 bhp +46 Nm |
| Stage 1 EcoPerformance with economy in mind | 446 bhp | 602 Nm | +26 bhp +42 Nm |
| Eco mapEconomy first | 443 bhp | 600 Nm | +23 bhp +40 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 Jaguar XK is expected to give 455bhp and 606Nm (+35bhp, +46Nm). The Stage 1 Eco keeps about 74% of that power gain and 91% of the torque gain, so you get 446bhp and 602Nm: 9bhp less and 4Nm 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 420bhp and 560Nm.
What this means for your XK
Without a turbocharger the improvement comes from ignition, fuelling and throttle mapping rather than boost, so expect a smaller but still noticeable change in response.
This car is listed with a Denso engine control unit. We read the ECU on your car and compare it with the software listed here before any work starts, so you know what to expect before you commit.
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 Jaguar XK 4.2 V8 R 420bhp?
We expect 446bhp and 602Nm against 420bhp and 560Nm as standard: up to +26bhp and +42Nm. 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 455bhp and 606Nm. Stage 1 Eco gives 9bhp less and 4Nm 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 (446bhp and 602Nm) and still care about running costs. Choose the Eco map (443bhp and 600Nm) 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.
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