TDI is used by the Volkswagen Group as a term to refer to its diesel engines.
You’ll see these three letters stuck on the back of a range of cars produced by its brands.
What does TDI stand for though, and what makes it different from other engines? This guide explains.
You’d be forgiven for thinking ‘D’ in TDI meaning diesel, but that’s not the case.
TDI stands for Turbocharged Direct Injection. Direct injection is when fuel is sprayed directly into a car’s cylinder rather than delivered through an intake manifold.
Direct injection diesel engines tend to be more efficient and produce less soot than older types of engines.
Though Volkswagen only applies TDI to its diesel engines, petrol engines will use direct injection technology in many cases too. Just not the branding.
Which cars have a TDI engine?
You’ll find the TDI moniker on a number of cars produced by Volkswagen. This also stretches to other brands under the VW Group, including Audi, Seat and Skoda.
Performance-oriented Audi S models such as the S4 and S5 use TDI power as well.
What types of TDI engines are available?
The core of the VW Group’s current crop of TDI engines is a 2.0-litre unit. This unit appears in a vast range of cars from the VW Golf to the Audi Q5 and many in-between.
What’s the difference between a TDI and a TSI engine?
While a TDI engine denotes a VW Group’s diesel engine, a TSI moniker refers to a turbocharged petrol engine from the manufacturer.
TDI engines will typically have better fuel economy compared to a TSI (especially if you do lots of long motorway journeys), as is usually the case with any diesel engine compared to petrol. TDIs tend to be more expensive to purchase though, and the fuel itself typically costs more per litre.
They’re used by the same brands too — you’ll find TSI on a number of Volkswagen, Seat and Skoda cars.