Jaguar XK (X150) 2006> 4.2 V8 R 420bhp remap figures
The Jaguar XK 4.2 V8 R 420bhp (2006>) is a petrol 4.2L model making 420bhp and 560Nm as standard. After a Stage 1 ECU remap we expect 455bhp and 606Nm - up to 35bhp and 46Nm more than stock.
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 | 420 bhp | 455 bhp | +35 bhp |
| Torque | 560 Nm | 606 Nm | +46 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 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 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 questions
How much power does the Stage 1 map give the Jaguar XK 4.2 V8 R 420bhp?
We expect 455bhp and 606Nm against 420bhp and 560Nm as standard: up to +35bhp and +46Nm. 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 Jaguar XK 4.2 V8 R 420bhp?
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: 446bhp and 602Nm expected. The Eco map is economy first: 443bhp and 600Nm. Both still sit above the standard 420bhp and 560Nm.
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 Jaguar XK figures
Other petrol variants
All petrol XK (X150) variants · XK (X150) 2006> overview · All Jaguar figures