Jaguar XJ 2003 - 2009 4.2 V8 SC 400hp
Real standard and upgraded performance figures for the 4.2 V8 SC 400hp engine in the Jaguar XJ 2003 - 2009.
The Jaguar XJ 2003 - 2009 4.2 V8 SC 400hp is one of the engines we work on regularly — here's what a stage remap typically changes for it.
| Horsepower (HP) | Torque (Nm) | |
|---|---|---|
| Standard | 400 | 540 |
| Stage 1 | 470 | 630 |
| Stage 2 | 505 | 675 |
- Make
- Jaguar
- Model
- XJ
- Generation
- 2003 - 2009
- Engine
- 4.2 V8 SC 400hp
- Fuel type
- Petrol
Frequently asked questions
Is Stage 1 tuning safe for the Jaguar XJ 2003 - 2009 4.2 V8 SC 400hp?
Yes — Stage 1 for this engine is a software-only remap calibrated to stay within its stock mechanical limits (turbo, clutch, fueling), so no hardware changes are required.
How much more power does the 4.2 V8 SC 400hp make after tuning?
Standard output is 400 HP / 540 Nm; Stage 1 on this engine typically reaches 470 HP / 630 Nm. Exact results can vary slightly with fuel quality and vehicle condition.
How long does a Jaguar XJ 2003 - 2009 4.2 V8 SC 400hp remap take?
Once your original file is uploaded through the member panel, most requests for this engine are completed within a few hours.
Can the 4.2 V8 SC 400hp be reverted to its original file?
Yes — we keep the original file on record for the request, so the ECU can be put back to stock at any time.