TDI Remap | TDI Tuning - Avon - Autotech Plus Ltd
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TDI Remap | TDI Tuning - Avon - Autotech Plus Ltd

TDI - Turbocharged Direct Injection


Turbocharged Direct Injection or TDI is a design of turbo diesel engines, which feature turbo charging and cylinder-direct fuel injection, developed and produced by the Volkswagen Group. These TDI engines are widely used in all mainstream Volkswagen Group marques of passenger cars and light commercial vehicles produced by the company (particularly those sold in Europe). They are also used as marine engines - Volkswagen Marine, and Volkswagen Industrial Motor applications.

IN simple terms, TDI is an acronym for Turbocharged Direct Injection. This type of engine has turbo charging capabilities as well as direct fuel injection. It was made by the Volkswagen group. It is known to offer high efficiency and higher power output with little emissions. These engines are diesel based.

The Direct Injection Engine was considered to be the savior of diesel, and there has been a growing market for TDI diesel cars. These cars are perhaps the most interesting in their creation, as they attempt to get the benefits of a gasoline engine, including fuel efficiency and engine power, without sacrificing the low cost fuel and environmental importance of diesel. The TDI is important to car makers as it offers them the chance to produce a car which does not lack for performance power. However, as with any other environmental technology, there are many pros and cons to producing and using TDI diesel cars.

What is TDI Engine
Best in the industry

What is TDI Remap
Better throttle response


When a manufacturer develops a new car they have to take into consideration all of the conditions it may be subjected to in all of the regions in which they intend to sell this model. This means instead of just optimising the ECU’s program or ‘map’ to deliver the best performance or the most fuel efficiency they have to make compromises to the map to take into account these potential differing operating conditions. These could include sub-standard fuels, extremes in temperature and altitude, differing emission laws and even the possibility that vehicle may not be serviced on a regular basis and in accordance with the manufacturers recommended instructions.

ECU remapping is taking a read from the ECU’s processing chip of the vehicles standard compromised map and adjusting various parameters within the map such as fuel pressure, boost pressure (on turbocharged applications) ignition advance and throttle pedal control amongst others to release the true performance from the engine. It is a completely safe process as it is just giving the engine the performance it should have had in the first place before all the compromises were applied to the original programming. Every engine will have its own unique map and by adjusting this we can fine tune the characteristics of the engine; unleashing more power and in many cases reduce fuel consumption too.


Unlike other forms of diesel engine, the TDI offers a lot of boost to the engine. This helps it to reflect the speed and rapid gear changes of a gasoline car, although diesel will still hold in the same gear for a while. There have been more improvements in the TDI recently, with the invention of an exhaust gas recirculation unit, which attempts to reduce the pollution produced by gasoline still further. The installation of catalytic converters also helps to reduce even the small amount of CO2 which the ordinary diesel car produces. There are significant reasons for purchasing a diesel car, including the fact that TDI diesel car fuel is often lower in price than gasoline, and that most diesel cars now offer a better engine performance than the closest gasoline engines.

Many see the modern crop of Turbocharged diesels as the future of road car tuning. a nation famed for its love of the petrol engine is starting to come around to the benefits of turbo diesel passenger cars in particular. These engines offer fantastic potential for reliable low cost tuning without removing any of the appeal of buying and running a turbo diesel powered vehicle, such as economy, reliability and longevity.

After your ECU upgrade to your turbocharged diesel engine, you will enjoy:
  • Increased horsepower
  • Increased torque
  • Better throttle response
  • Smoother power delivery
  • Improved fuel economy
  • Safer overtaking


TDI for diesel cars has helped those vehicles to become the close rivals of gasoline powered cars, but they have not come without cost, which is chiefly centered around how much the customer is prepared to pay for his vehicle. With TDI cars costing more than their gasoline counterparts, they are still only bought by those with a real commitment to the environment, or who want to save money by converting the car to biodiesel fuel.


Volkswagen Jetta TDI

Perhaps the most familiar of the TDI cars is the VW Jetta TDI. These cars, including the sports utility vehicle known as the Jetta Sportswagen TDI, all have a good fuel efficiency from their 2.0 engine. This car came out on top of a survey which calculated how much diesel cars saved over 5 years compared to their gasoline relatives, with savings of as much as $6,000 over this 5 year period, or around 70,000 miles. This helps to recoup some of the costs which diesel cars include in their original price

Alfa Romeo

A less familiar car is the Alfa Romeo, and its Alfa MiTo diesel car. This sells rather well in the European continent, where the rules for diesel emissions are much stricter. The Mito uses a Multi jet TDI engine to provide power, and is an excellent little car for using in the city


The BMW is in a class of its own, and many who are considering going for a diesel car overlook the splendid attempts that BMW has made to produce a good car. The BMW 335d is a diesel car which is considered to get around one-third more out of diesel than its counterpart can manage on gas

Kia Borrego

Unlike the other cars mentioned here, this is a diesel car which is specifically intended to be used with biodiesel. Using this car can help you to get around the city easily, and it is also considerably more cost-effective than the other cars, despite being an SUV. Most of these cars will probably be bought by urban drivers, where the TDI will not be brought out to the best effect, but it is still the cheapest version around

Mercedes Benz 320 BlueTec Turbo

Mercedes is not new to the diesel landscape, or in providing turbo diesel cars for mass consumption. Their 1985 300D was a very popular diesel engine that came with a turbo. Today's newer turbo diesel Mercedes has a new engine concept called BlueTec. Because of stringent emissions and pollution rules, Mercedes has developed their BlueTec turbo. This runs on their new AdBlue urea-injection technology that cleans up the exhaust from the 215-hp, 3.0-liter turbo-diesel engine. Fuel economy is not an issue either. Mercedes boasts that this turbo powered diesel will reach over 600 miles on a tank of gas

Volkswagen Golf Turbo

Talking about the most fuel efficient cars, the conversation has to include the VW Golf. The 2.0L turbo powered engine will reach up to 47 MPG and thanks to the glow plugs in the engine block, colder weather is not an issue anymore with the diesel engines. The Golf, renamed the Rabbit in the U.S. has a similar package than the Jetta TDI, but in a smaller compact version. Customers have given the Golf very high reviews in stating that even though the car is smaller than a sedan, there is still room to move in it

Audi A3 Turbo Diesel

What has been called a "highly efficient diesel small luxury car", the Audi A3 with a TDI turbo diesel is actually a re-engineered version of the previous A3. With 140 hp and 236 ft-lb of torque coming from the four-cylinder turbo-diesel, the Audi still reaches over 40 MPG on the highway. It is not common to find a powerful, and luxurious, sedan that still has that kind of fuel economy. In direct competition with several hybrid vehicles, such as the Toyota Prius, the A3 is able to deliver with tremendous customer reviews. While the pricing is still a little more than the Golf, or Jetta, it is a more luxury/turbo/sports car than it is a hatchback


Fuel needs oxygen to burn and the engine has to be supplied with huge quantities of air to get enough. You can solve this problem with a bigger engine – or you can solve it with a turbocharger – as in the TDI. Driven by the exhaust gases, it squeezes air more tightly into the cylinders.

After being drawn through the turbocharger the air is then cooled by passing it through an air to air intercooler (cool air takes up less space than hot air), before entering the combustion chamber where diesel is injected directly into the cylinders at very high pressure through a nozzle. It’s this intensive mixing of highly atomized fuel with the cooled compressed air that leads to better, more efficient combustion.

Your driving experience is quiet and refined because effective sound insulation keeps noise to a minimum, while hydraulic engine mounts ensure smooth, low-vibration running.

How TDI Engine works
Safer overtaking

Saving Fuel with TDI Remap
10%+ fuel saving on diesel engines


When we remap a vehicle, especially when fuel saving is the priority we focus on improving the low end torque in particular and widening the power-band as far as we can.

This increase in low end torque will mean less throttle pedal input is required to maintain cruising speeds, when fully laden or when on a gradient. It will also mean that the vehicle will be more comfortable in higher gears at slower speeds as well requiring fewer gear changes overall.

If you combine these factors with adjusting your driving style to make the most of the extra low end torque you will see an improvement in fuel consumption. This is most effective on turbo-diesel engines where the savings could be as much as 20%!


We do not change any hardware in your vehicle, we just modify the operating parameters in the ECU’s program or ‘map’. In many cases the map stored on the ECU’s processor can be accessed via the on-board diagnostics port (OBD) in the vehicle, normally found under the dashboard. In some newer models the ECU will have to be removed from the vehicle and the casing opened, our technicians will then use specialist tools to read the original map straight from the processing chip.

The technician will then upload the original map to our map writing team who will adjust the parameters to maximise the performance, fuel economy or a clever blend of both. Depending on the vehicle and ECU type the remapping process can take under an hour and if at any time you wish to return your vehicles ECU to its original default settings, this can be done easily and free of charge as we always keep a copy of the original software as a backup.

What do you actually modify
Increased torque – up to 35%