Engine Tuning

A reputable tuning company will offer before and after dyno testing to prove the output increases as they are claiming and will return your car to standard without charge if you are not happy with the results within a specific time frame.

The output will be affected by engine condition, fuel quality and any modifications; the tuner should be able to assess your vehicle and inform you of any rectification work required to achieve the claimed outputs, or decline to tune a vehicle that is not suitable for tuning.

This requires diagnostic equipment which should be hooked up before and after tuning. The tuner should confirm correct operation using key performance indicators such as airflow, boost pressure, air-fuel ratios, injected quantity etc. Also ask if they can prove the power and torque gains, using a chassis dynamometer or data logs?

A reputable tuning business will keep your original calibration on file for an agreed period of time – and restore the vehicle to its original state if requested within that period. This should be at least 3-5 years.

There is no set industry charge for returning a vehicle to its original state of tune. So, beware of hidden charges if you do want to revert to your original state.

An investment of many thousands of pounds is required for the latest equipment and keeping the software licences up to date. The price you pay should reflect this investment if it seems too cheap or a lot less than other quotes ask yourself why?

Are they using cheap cloned equipment or files that have been bulk downloaded from the internet? Ask if they can remap newer cars – a 2018 BMW 320d, for example – this is an easy way of ensuring the equipment is up-to-date and genuine.

It takes years of training and experience to correctly tune a car, so it is a good idea to ask what qualifications and/or experience the technician who will be working on your car has.

If the software is not written in-house ask how long the company that is writing the software has been operating. Do your own research online, there have been many software companies that have entered the market offering cheap files, but they seldom last long or keep re-inventing themselves.

If they specialise in a particular make or model they should have the expertise to explain what common faults to look out for. Ask about your vehicle, they should be able to answer confidently.

A battery support unit (which is not just a battery charger) should be connected during the read/write process. A minimum of 60 amps should be considered, prolonged periods of key-on/engine-off are required during the remapping process.

Engine ancillaries can also cycle such as cooling fans which quickly drain the battery. The ECU can become damaged beyond repair (bricked, as it is known) if the battery voltage drops below a critical level during flashing. Ask if a battery support unit will be used, and ask what current amp rating it is. If they answer that they will use a battery charger/jump leads, or that such a device isn’t necessary, we urge you to walk away.