If you’ve looked at almost any modern Audi, you’ve probably seen the letters TFSI after the model name. They identify the type of petrol engine the car uses — but what does TFSI actually mean?
TFSI stands for Turbo Fuel Stratified Injection, Audi’s name for petrol engines that combine turbocharging with direct fuel injection. The technology is designed to provide strong performance while improving fuel efficiency compared with older, naturally aspirated petrol engines.
You’ll find TFSI engines across much of Audi’s range, from smaller models such as the A1 and A3 to larger saloons and SUVs. You may also see numbers such as 30 TFSI, 35 TFSI or 40 TFSI. These numbers relate to the car’s approximate power output rather than its engine capacity — something we’ll explain below.
TFSI shouldn’t be confused with TDI, which Audi uses for diesel engines, or TFSI e, which identifies certain plug-in hybrid models.
In this guide, we’ll explain how TFSI works, what Audi’s TFSI numbers mean, how it compares with TSI and FSI engines, and what to consider if you’re buying a used Audi with a TFSI engine.
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How does a TFSI engine work?
A TFSI engine combines two important petrol-engine technologies: turbocharging and direct fuel injection.
The turbocharger uses exhaust gases to force more air into the engine, allowing it to produce more power without simply relying on a larger engine. Direct injection delivers fuel directly into the combustion chamber, giving the engine more precise control over how fuel is used.
Together, these technologies allow Audi to produce relatively compact petrol engines that can deliver strong performance while also improving fuel efficiency. The exact power, economy and characteristics will naturally vary depending on the particular TFSI engine and Audi model.
TFSI is closely related to other Volkswagen Group petrol-engine terminology, particularly TSI and the earlier FSI engines. The basic differences are shown below.
| Engine Type | Turbo | Fuel Injection | Brand |
|---|---|---|---|
| TFSI | Yes | Direct | Audi |
| TSI | Yes | Direct | Volkswagen |
| FSI | Generally No | Direct | Audi/VW |
What does TFSI e mean?
TFSI e is Audi’s name for its plug-in hybrid (PHEV) models. These cars combine a TFSI petrol engine with an electric motor and a rechargeable battery, allowing them to drive for a certain distance using electric power alone.
Unlike a standard hybrid, a TFSI e can be plugged in to recharge its battery. For shorter journeys, this can allow drivers to use electric power more frequently, while the petrol engine remains available for longer trips or when additional performance is needed.
The electric-only range, performance and fuel economy vary considerably between different Audi TFSI e models, so it’s worth checking the specifications of the particular car you’re considering.
Should you choose a TFSI engine?
TFSI engines can be a good choice if you want the performance of a turbocharged petrol engine without necessarily moving to a larger engine. They’re widely used across Audi’s range, so there are plenty of different power outputs and models to choose from.
Whether a TFSI is right for you will depend on how you use your car. Petrol engines can suit drivers who make a mixture of shorter and longer journeys, while someone covering particularly high annual mileage may also want to compare diesel, hybrid and electric alternatives.
If you’re buying a used Audi, don’t judge the car by the TFSI badge alone. The age, mileage, service history and condition of the individual vehicle are all important, and different generations of TFSI engine can have different maintenance requirements.
If you’re considering changing your current car, it’s worth finding out what it’s worth before deciding what to buy next. You can get an instant car valuation and compare your options.
When you’re ready to change, you can also sell your car online and receive offers from trusted UK buyers.
Frequently asked questions
What does TFSI stand for?
TFSI stands for Turbo Fuel Stratified Injection. It’s Audi’s name for petrol-engine technology that combines turbocharging with direct fuel injection.
Is a TFSI engine good?
TFSI engines are known for delivering a good balance of performance and fuel efficiency, making them popular in modern petrol cars.
What is the difference between TFSI and TSI?
TFSI is Audi’s version of Volkswagen Group’s turbocharged petrol engines, while TSI is the equivalent branding used by Volkswagen.
Should I sell my car before upgrading?
If you’re considering upgrading your car, checking its value and comparing offers can help you make a more informed decision.