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ECU Remapping

What is the Engine Control Unit (ECU)?

The ECU could be described as your vehicle’s ‘brain’, it contains a processor, complicated electronic circuits and software developed to make your engine run.

The ECU is handed information from sensors installed on various parts of the engine. It analyses this information such as temperatures, accelerator pedal position, oxygen content in the exhaust gases, as well as many other parameters. Using the information from these sensors it can then tell the injectors right quantity of fuel to supply and at the right time in each cylinder to provide optimum performance and efficiency in all driving conditions and scenarios, from parking to pulling away & overtaking.

What is ECU Remapping?

When a manufacturer releases a car, it is then sold in countries all over the world. Across these different parts of the world there are some extreme differences in the conditions a vehicle is subjected to, including sub-standard fuel qualities, extremely cold (and hot) temperatures, altitude, differing emission laws and even the possibility that vehicle may not be serviced in line with the manufacturer recommendations.

Remember we said the ECU contains software, this software is often called the engine/ECU maps, the maps on your vehicles ECU contain “tables” of information that tell it what to do with the information it received from all the sensors. Instead of developing a different map for a vehicle to be released in different countries, the manufacturer will instead focus on producing a robust software that is suitable for vehicles being used everywhere. However to do this they have to compromise on things like engine performance and efficiency slightly, in order for the engine to work correct in all the differing conditions we mentioned above.

By adjusting these maps/tables we can fine-tune the ECUs control of the engine; allowing more power output and in many cases reducing fuel usage as well, and as you know your vehicle is being used in our own climate and is being looked after correctly, this is generally a safe process and stays within the limits of all engine components. To remap your ECU we need to take a reading from the ECU’s processing chip of the vehicles standard compromised software so we can adjust various parameters within the map. Including fuel pressure, boost pressure (on turbocharged engines) ignition timing and throttle pedal control, amongst many others, to restore the true potential from the engine.

OBD Remapping

One of the methods we use to remaps a vehicle is through the OBD port, this is the most efficient and non-intrusive method of accessing the ECUs software. TO put it simply remapping via the OBD port allows us to offer some truly incredible results without even opening the bonnet or touching your engine! With specialists tuning tools, we can bypass protections on the vehicles ECU, and gain access to the software/maps inside. We can then use the same process once we have modified the maps to reinstall the new software to the ECU, much like carrying out an update on your phone.

BDM Tuning

Remapping a vehicle via the OBD port is not always possible: some older vehicles may not have an OBD port, the port may be faulty or the ECU may block access to tuning via the OBD port if it has not been bypassed yet. In this case there are several other methods available that we can use to access the software inside the ECU. Back Door Module (BDM) tuning is the process of connecting directly to the circuit board of the ECU, using specially developed frames and equipment to hold the ECU in place while data connections are pinned, clipped or soldered to the circuitry. This method therefore requires the ECU to be removed from the vehicle and worked on in a suitable environment.

South West DPF Cleaning preparing to remap grey van for client
Bentley Car Getting ready for remap by South West DPF Cleaning

What benefits will I get from remapping my ECU?

ECU remapping will not only improve the engine power and torque figures on paper; it will also sharpen the throttle response and improve the power-band. To the driver this will make the vehicle feel a lot livelier to drive and the engine more flexible, meaning less changing gears. With the extra torque on offer, especially at the bottom of the rpm range, you may be able to see a fuel saving. This is because it will require less accelerator input to maintain motorway speeds, you can drive in a higher gear at a slower speed as well as helping significantly when towing or on gradients.

What benefits will I get from ECU remapping a turbocharged diesel engine?

Turbo Diesel engines provide a potential for reliable low cost tuning without losing any of the appeal of a turbo diesel powered vehicle, such as the amazing economy, lifespan and torque delivery.

Remapping a turbo diesel engine you will see the following benefits –

  • Increased horsepower
  • Increased torque
  • Better throttle response
  • Smoother power delivery
  • Improved fuel economy
  • Safer overtaking

What benefits will I get from ECU remapping a turbocharged petrol engine?

Similarly to Turbo diesel engines, turbocharged petrol engines provide much improved outputs over their non-turbocharged counterparts. They are also ideally suited to remapping and can offer some incredible results from an engine remap, having control over the boost provided by the turbocharger plays a big part in this.

Remapping a turbo petrol engine you will see the following benefits –

  • Increased torque
  • Better throttle response
  • Smoother power delivery
  • Safer overtaking
  • Increased horsepower

Unfortunately improvements in fuel consumption on petrol engine vehicles are rare and cannot be promised in the same way as diesel vehicles.

What benefits will I get from ECU remapping a non-turbocharged petrol engine?

A remapped petrol engine without turbocharging can benefit from an 8-15% power increase depending on the engine, with added torque in the low rpms, and increased throttle response. So although these results can’t match the improvements from a turbocharged engine, depending on the vehicle you may still be able to see a noticeable difference in the performance on offer.

For higher power improvements, ‘after market’ tuning hardware such as performance exhausts, high flow air intakes and upgraded camshafts are the only option really. However these can only be fully utilised by the engine once the necessary adjustments have been made within the ECU, so a remap is essential if you have installed any performance modifications to your n/a petrol engine.

Fuel savings after remapping?

When your vehicle is remapped with either our green or blue tuning options, we put emphasis on improving the low end torque and widening the power-band as far as we can.

By increasing low end torque delivery, less throttle pedal input is required to maintain an average cruising speed, even more so when fully laden or when on travelling up a gradient. The vehicle will be more comfortable in higher gears at slower speeds, requiring fewer gear change due to the improved power band. By naturally adjusting your driving style to make the most of this extra low-rpm torque, this is where you will see an improvement in fuel consumption. Improvements in fuel economy are greatest on turbo-diesel engines, where the savings could be as much as 20%.

What do you modify in my vehicle?

A “stage 1” engine remap does not require any hardware modifications to your vehicle, the only thing changed is the ECU’s program or ‘map’. If tuning protection is not active on your ECU, then the whole process can be carried out via the on-board diagnostics port (OBD) in the vehicle, meaning we don’t even need to open your bonnet! In some newer models or those with tuning protection applied, the ECU may have to be removed from the vehicle and the casing opened, this is so our technicians can use specialist tools to read the original maps and install the ew modified software once the process is complete.

Is ECU remapping legal?

It is completely legal to have your vehicle remapping, your should however notify your insurance company, as it is a vehicle modification and improves vehicle performance

SouthWest DPF Cleaning and Top Tuning Van
SouthWest DPF Cleaning customer

TCU Remapping

Most modern vehicles with automatic transmissions are fitted with a TCU (Transmission Control Unit). This is what controls the transmissions mechanical operations e.g. gear shift and torque limitation. The TCU and ECU in your vehicle work together by sending and receiving real time data across the vehicles network system and make sure you get a smooth driving experience. When tuning certain vehicles, it is often recommend to also have the TCU remapped alongside the main engine ECU, this helps to ensure both control units continue to work in harmony and will make sure no issues are encountered with things like torque limits not matching between them.

Automatic transmissions work in different ways depending on what type you have. So some can be improved more than others, below are some of the improvements you can expect from a TCU remap:

Shift Speeds – Increasing the speed in which the gearbox changes gear.

Torque Limiters – Increasing the TCU torque limiters ensures the transmission cannot limit the performance of the engine.

Hydraulic Pressure – Increasing the hydraulic pressure can increase clutch clamping pressure to prevent clutch slip on highly tuned vehicles.

Shift Points – Changing the rpm limiter of the engine is often not possible without modifying the TCU software.

On certain transmissions advanced options like the following can be activated: Launch Control, Full Manual Mode, Kickdown Delete.

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