What a proper before-and-after looks like

• Baseline run on arrival. ambient temp logged, fuel quality noted (always tankful of Shell V-Power or BP Ultimate for the baseline)
• Two or three back-to-back baseline runs. averaged, to remove run-to-run variation. This is the honest start number
• Remap performed on the bench or on the car. Stage 1 or Stage 2 depending on your spec. See our ECU remapping page for what each stage involves
• Cool-down period. we let the engine and intercooler return to baseline air temperature before re-running
• Same number of post-remap runs. back-to-back, averaged. Same dyno settings, same ambient correction
• Single overlaid printed graph. before in one colour, after in another, peak figures called out clearly

Why same-day matters

If we baseline today and remap next week, the air temperature, the fuel quality, the tyre pressure, even the dyno-room humidity will be different. The numbers will not be directly comparable. By doing baseline, remap and after-run all on the same day at our Slough workshop, we eliminate every variable except the remap itself.

Drivers across Berkshire choose us specifically because of this. You can see exactly what the remap did to your specific car, on your specific dyno session, with no tuner-friendly fiddling. Real data, real proof, real value for the money you spent on the remap.

What if the remap underperforms?

Honest answer: it sometimes does. Cars are not all equal. A boost leak, a worn turbo, a clogged DPF or a tired clutch can all limit what a remap can deliver. If the after-graph does not show the expected gain we will tell you straight, refund the difference where appropriate, and recommend the underlying fix.

We would rather lose a remap sale and keep an honest reputation than over-promise on power and have you back complaining a month later. Slough and Berkshire enthusiasts know this. That is why most of our remap work comes from word of mouth.