Dyno day: how to prepare your car and what happens, step by step

Many people arrive at the dyno for the first time without knowing what to expect. You don't need to be an engineer, but a little preparation makes the day smoother and the measurements more reliable. Here is the process as we run it at our own workshop, on our 4WD Dimsport dyno.

Before you come

1. Book a slot. Tell us the make, model, engine, mileage and what you want to achieve: Eco, Stage 1, something more, or simply a measurement to see where you stand.
2. Write down what has been changed. Exhaust, air filter, intercooler, a previous remap, different tyres. Anything you know helps, even if it seems minor.
3. Fill up. At least half a tank, with the fuel you will be using afterwards. If you plan to run 98 or 100 octane, arrive with it in the tank.
4. Check the basics. Oil and coolant levels, no warning lights on the dash, tyres free of damage and bulges, correct pressures. On the dyno the wheels turn at road speed, so a bad tyre is not a detail.
5. Empty the boot. Loose items inside the car are not needed, especially while the engine is running at full load.

At the workshop

1. A short chat and a visual check. We look for leaks, loose hoses and anything visible to the eye, and read the fault codes from the ECU.
2. Positioning and strapping. The car goes onto the rollers and is secured with straps. Because our dyno is all-wheel drive, 4x4 cars are measured the way they drive on the road, without disabling the drivetrain. A fan in front of the car provides cooling.
3. Warm-up. We don't measure a cold engine. We wait for both coolant and oil to reach operating temperature so every run happens under the same conditions.
4. Standard runs. We do more than one run in standard form to confirm the results repeat. At the same time we log pressures, temperatures and ignition corrections. If the engine is making noticeably less than it should, we stop here and look for the cause.
5. Read and backup. We read the ECU software and keep a copy of the original so it can be restored if needed.
6. Calibration. The new calibration is developed at our workshop for that specific engine and written to the ECU.
7. Runs after. More runs under the same conditions, with logging. If a value is not where we want it, we correct it and measure again. Repeatability on the dyno is in the order of 1–2 PS, so the difference you see is real.
8. Road test. The dyno shows full load. Part-throttle behaviour, pulling away and gear changes are also checked on the road.

What you take home

A graph with the power and torque curves before and after, from the same machine, on the same day. Look at the shape of the curves in the rev range where you actually drive first, and the peak figure second. If you want to read it properly, we have written a guide to dyno graphs.

Common questions

Can the dyno harm the engine? It runs at full load for a few seconds at a time, like a hard acceleration on the road, with cooling and the values monitored. A healthy engine has no problem with it. If something is wrong, we see it in the log and stop.

Why is my number different from another dyno? Every machine has its own calibration and procedure. What matters is the difference before and after on the same dyno.

What if a problem is found? We tell you before writing anything. Sometimes the repair alone brings back the missing performance.

See what is available for your vehicle in the car finder or book a dyno slot.