How to tune a diesel car

There’s a misconception among drivers today that while petrol engine remaps are great in terms of better overall performance, the same can’t be said for diesel engines.

‘Adding more horsepower loses fuel efficiency,’ they say, ‘and it damages diesel engines.’ No-one seems to know where these myths have come from – but myths are certainly what they are. And actually, because diesels are designed to run at lower revs than petrol engines, there is better optimisation potential when it comes to ECU remapping.

A diesel engine tune-up done properly by a company like ours has just as many benefits as a petrol engine remap. We aim to produce top-of-the-range remaps for both petrol and diesels alike, and you can be assured that if you choose Mobile Eco Tuning you’re guaranteed the best possible service, petrol or diesel.

What’s involved in a diesel engine remap?

When your vehicle arrives at our workshop, we will perform a full diagnostic health check to make sure it is suitable for a remap. We also offer a ‘rolling road’ dyno session that helps us to compare power output before and after the remap.

Once this is done our engineers will plug their laptops into your engine’s diagnostic system to begin the process of adjusting the Engine Control Unit (ECU) so that various parameters can be optimised. These include fuel injection timing, turbo boost pressure and air-to-fuel ratios. When these modifications have been tweaked to our satisfaction the results will show an increase in power, greater torque, sharper throttle response and smoother power delivery. In short, these changes make your diesel car or van more responsive and enjoyable to drive.

As for fuel economy, this can improve – BUT that all depends on how you drive your car post-remap, and we can’t guarantee fuel savings on that basis.  Fuel efficiency is down to the engine’s air-to-fuel ratio, and if the engine is running inefficiently, it’ll need more fuel to produce the same amount of power. By tuning the engine to run at its most efficient level, the air-to-fuel ratio is optimised. Plus, more torque means fewer gear shifts and reduced throttle pedal movements, resulting in better mpg. But that’s down to you as the driver!

Commercial diesel vehicles

Remapping allows for customization of the vehicle’s performance characteristics to suit individual preferences or specific driving conditions. If you’re using your diesel vehicle for work purposes – for example, you’re a delivery driver or a builder – an increase in torque and HP means you’ll be able to accelerate more quickly and handle heavier loads with ease. The same goes for larger agricultural and construction vehicles.

Diesel remap enhancements

There are a number of extra mods we can carry out on your diesel car or van to really give it a good kick when you get out on the road or the track.

• Hard-cut limiter

Diesel engines, while reliable and efficient, often lack the excitement factor. However, a hard cut limiter software upgrade, known as a ‘popcorn limiter,’ can inject some excitement into these steady workhorses. A hard cut limiter supplies diesel engines with the dynamic sounds of roars, bangs, and pops that are characteristic of high-revving petrol engines. This upgrade works in tandem with a DPF or CAT delete, and it operates by cutting off fuel injection at a predetermined RPM, creating an explosive collection of engine sounds as it hovers around the RPM threshold.

• Fault code and DTC removal

When it comes to performance tuning modern vehicles, Diagnostic Trouble Codes (DTCs) can be a double-edged sword. While they’re essential for pinpointing malfunctions, they can become a hindrance when upgrading a car’s performance. At MET, our experts utilize the OBD II port to recalibrate the ECU, selectively deactivating these DTCs. This ensures that your vehicle operates seamlessly with any performance enhancements, free from unnecessary error messages and without compromising the joy of driving.

DTCs like P0420, which signals ‘low catalyst system efficiency,’ often arise after installing performance hardware such as sports catalytic converters or decats, which alter exhaust flow and sensor readings. By disabling such DTCs, our engineers guarantee that your vehicle reaps the full benefits of performance upgrades, allowing for an unimpeded and optimized driving experience.

• Speed limiter removal

The full potential of your diesel vehicle can be unlocked with our expert speed limiter removal service. We can adjust or remove your vehicle’s speed limiter, allowing you to experience its maximum power and true top speed. Ideal for racing enthusiasts or those seeking a more responsive drive, our service ensures your vehicle performs at its best.

Our comprehensive ECU remapping service includes speed limiter removal for diesel cars, vans, and trucks, enhancing your vehicle’s performance beyond factory settings. Note that for certain vehicles, speed limiters are mandated by law, and their removal is not permitted. MET adheres to legal standards and will not remove speed limiters where it is illegal to do so.

Optimizing a diesel vehicle through ECU remapping and limiter modifications can profoundly transform your driving experience. This process promises not only a boost in performance and efficiency but also a more pleasurable journey, making it a compelling consideration for diesel vehicle enthusiasts. For more information about how Mobile Eco Tuning goes about diesel remaps, contact us here or give us a call on 01934 318857.