Some cars don't fit a stage. Unusual hardware combinations, imports, motorsport builds, "previous tuner gave up" projects — they need a calibration developed specifically for the car in front of us, iterated against logged data until the numbers behave. That's this service. You watch it happen, and you keep the data.
A stage file answers a known question. Custom work is for when the question itself is new.
When does a car need custom development? When its combination of parts has no proven calibration to start from: a hybrid turbo with water-meth, an imported JDM engine the UK databases barely know, a motorsport build with individual throttle bodies, or simply a car that three other tuners have "nearly sorted". Off-the-shelf logic — even good off-the-shelf logic — assumes a known quantity. Your car isn't one.
So we measure instead of assume. The session starts with a baseline: full health check, then logged runs capturing boost behaviour, air-fuel ratios, timing corrections, rail pressure, temperatures — fourteen-plus channels of what the engine is actually doing. The calibration is then developed in deliberate steps, each revision logged and reviewed before the next. Boost comes up gradually. Fuelling is verified at every load site. Timing advances only where the knock data says it can.
Sign-off is a number on a screen, not a feeling in the seat. When the logs show stable boost, safe mixtures, clean timing and repeatable performance, the file is done — and you receive the evidence: a data pack showing before, after, and every step between. If a dyno session is the right tool for your build, we arrange and run it as part of the development plan.
What actually happens across a custom session — tap any stream for the detail.
Logged stock-state runs so every later change is measured against reality, not memory.
You cannot prove improvement without a baseline. The first logs capture how the build behaves before we change anything — including any problems the previous tune left behind. Several "tuning" jobs become diagnosis jobs at this step, and finding that out early is the cheap version.
Targets developed in measured increments, with wastegate/actuator behaviour verified at each step.
Boost control on a modified car is its own engineering problem — spring pressures, actuator preload and control logic all interact. We bring targets up in steps, verifying control stability before adding more. Overshoot tamed on the logs beats overshoot discovered at the redline.
Mixtures developed and verified across the whole load map — not just the headline pull.
Wideband data drives every fuelling decision: cruise sites for economy and cleanliness, transition sites for response, full-load sites for power with cooling margin. Injector duty and rail pressure headroom are tracked throughout so the system is never running on hope.
Advance found by listening to the engine's knock response, cylinder by cylinder.
Every engine has a timing point where efficiency peaks and another where knock begins; custom work maps the gap between them for your engine, your fuel, your hardware. Corrections are watched per cylinder — one grumpy cylinder caps the whole map until we know why.
Cold start, idle, tip-in, part-throttle — developed with the same care as the power.
A custom car that stalls at junctions is a failed project whatever the dyno says. Real development time goes into the unglamorous sites — idle stability, throttle tip-in, low-speed manners — because that's where you live with the car every day.
Final logged runs against the baseline — the file is signed off by the data, then documented to you.
Sign-off runs repeat the baseline conditions so before/after is a fair fight. You leave with the proven file on the car, the data pack in your inbox and the entire revision history archived — gold dust for future work, insurance conversations or resale.
Representative custom results — every one different, because every brief was. Scrub the curves, then tell us about yours.
| Build | Power (before → after) | Torque (before → after) |
|---|---|---|
| VW Golf GTI — custom map | 245 → 315 bhp | 370 → 460 Nm |
| BMW M140i — custom map | 340 → 430 bhp | 500 → 620 Nm |
| Mercedes-AMG A45 | 360 → 420 bhp | 450 → 520 Nm |
From build review to data pack — the structure every custom session follows.
Three truths about bespoke calibration that deserve to be said before any money moves.
From £350 per session against £150 for a Stage 1 is a real difference. You're buying development hours, logging, review and proof — not a file transfer.
If your car would be served perfectly well by a stage file, we'll say so and charge you the stage price. Custom is for cars that need it — selling it to cars that don't is just margin-farming.
Development optimises what's there; it cannot conjure flow from a small turbo or fuel from a maxed pump. Sometimes the honest output of a session is a hardware shopping list.
You'll see the limitation on the logs yourself — boost tapering, injector duty pegged. We show you exactly where the wall is and what moves it. Data ends arguments.
If the car arrives with unknown software, we're developing on a mystery. It costs time to unpick — occasionally more than starting clean would have.
We read what's on the car first and tell you what we've found. Where a clean factory base is the faster route, we source one for your ECU before development begins.
Not sure which side you're on? Describe the build — we'll tell you straight whether it needs custom work or just a well-chosen stage.
When your car's combination of hardware, history or intended use falls outside what proven stage calibrations cover: unusual mod combinations, imported or rare engines, motorsport builds, water-meth or flex-fuel setups, or cars other tuners have left misbehaving. If your car is a common platform on common bolt-ons, a stage file is honestly the better-value answer — and we'll tell you that.
Development is driven by logged data either way — boost, wideband AFR, timing corrections, temperatures across fourteen-plus channels. For builds that warrant it we arrange dyno sessions as part of the plan; for others, controlled logged road development produces equally rigorous results. The tool follows the build's needs, and the evidence standard never changes: the logs sign the file off.
Your baseline logs, the verification logs at sign-off, and a summary of what changed and why — boost behaviour, fuelling, timing strategy. Plus your original file and the full revision history archived with us. It proves what was done, protects you in insurance conversations, and adds genuine credibility if you ever sell the build.
It's some of our most satisfying work. We read what's on the car, log how it actually behaves, and show you the problems on data — then either repair the calibration or rebuild from a clean factory base. You get a before/after comparison that makes very clear what was wrong. We're diplomatic about the previous tuner; the logs don't have to be.
Most single-purpose builds are developed and signed off within one full session. Bigger projects — fresh Stage 3 hardware, motorsport prep, flex-fuel — sometimes earn a second session after parts bed in or the spec evolves. The scope conversation before booking sets expectations honestly, and you'll never be drip-fed surprise sessions.
Yes — imports and less common platforms are a natural fit for custom work, since UK off-the-shelf files barely know them. The honest caveat is ECU access: a few control units are locked or need bench work, and one or two are genuinely impractical. Send the exact model and year with your enquiry and we'll confirm access before anything is booked.
Hybrid-turbo projects planned and proven — custom development is how every one gets signed off.
Custom quote Plan a Stage 3 // Fix first Fault FindingMystery misbehaviour solved on live data before development begins — half of "bad tunes" are hiding a fault.
From £40 Find the fault // Proven route Stage 2 ECU RemapCommon platform, common bolt-ons? The developed stage calibration is the better-value answer.
From £250 Compare Stage 2Custom calibration from £350 per session — developed on logged data, proven before handover, documented forever. Start by telling us what you've built.