What Do Audi Engine Numbers Like 30 TFSI, 35 TDI and 50 TDI Mean?

Audi engine badges can be confusing at first. Instead of familiar labels like “2.0 petrol” or “1.6 diesel”, you’ll historically see names such as 30 TFSI, 35 TDI, or 50 TDI on the boot of an Audi. However, as of 2026, Audi has begun removing these double-digit numbers from the rear of its newest models (like the A5 and Q6 e-tron) to create a cleaner look, though they remain the official way to classify power levels in brochures and price lists.

These numbers are not engine sizes. They represent power levels, and Audi uses them to make it easier to compare petrol, diesel, and hybrid engines across different models.

This guide explains:

• What TFSI and TDI mean

• How Audi’s numbering system works

• What 30, 35, 40, 45 and 50 actually stand for

• Which Audi engine type suits different drivers

Quick definitions

TFSI meaning: TFSI is Audi’s name for its turbocharged petrol engines that use direct fuel injection.

TDI meaning: TDI is Audi’s name for its turbocharged diesel engines designed for fuel economy and pulling power.

Also Read:  Car Engine Meanings

What does TFSI mean on an Audi?

TFSI stands for Turbocharged Fuel Stratified Injection. It is Audi’s petrol engine technology that combines a turbocharger with direct fuel injection.

TFSI engines are used across much of the Audi range, including the A3, A5, and Q3. (Note: The entry-level A1 and Q2 are being phased out in 2026). They are known for:

• Smooth and quiet driving

• Strong acceleration for their size

• Lower fuel use compared to older petrol engines

If you mostly drive in towns, commute daily, or do mixed journeys, TFSI engines are often the best fit.

What does TDI mean on an Audi?

TDI stands for Turbocharged Direct Injection. This is Audi’s long-established diesel engine technology.

TDI engines focus on torque and efficiency, making them well suited to:

• Motorway driving

• High annual mileage

• Carrying heavier loads

TDI engines remain popular in larger models such as the A6, Q5 and Q7.

TFSI vs TDI: what is the difference?

TFSI engines are petrol. TDI engines are diesel.

In simple terms:

• TFSI engines feel smoother and quieter

• TDI engines pull harder at low speeds and use less fuel on long runs

Drivers who do short trips often prefer TFSI. Drivers who spend a lot of time on the motorway often prefer TDI.

How Audi’s engine naming system works

Audi introduced its number-based system in 2017. Instead of showing engine size, the badge shows a power band. A higher number means more power, regardless of whether the engine is petrol, diesel, or hybrid.

Important Update: Audi has simplified its model naming. Even numbers (like A4, A6, Q4, Q6) are now reserved for fully electric e-tron models, while odd numbers (like A3, A5, A7, Q3, Q5) are used for internal combustion and hybrid models. For example, the car formerly known as the A4 is now the Audi A5.

Audi engine number bands explained

Audi’s numbers roughly match these power ranges (measured in Brake Horsepower/PS):

What does 30 TFSI mean?

A 30 TFSI Audi is a lower-powered petrol engine, producing around 110 to 116 bhp. It is commonly found in the Audi A3. This level suits drivers who want lower running costs and easy town driving.

What does 35 TFSI mean?

A 35 TFSI Audi produces around 150 bhp. This is Audi’s most popular petrol level and is widely used across the A3, A5, and Q3 ranges. It offers an ideal balance between performance and efficiency for everyday driving.

What does 40 TFSI mean?

A 40 TFSI engine normally sits around 204 bhp. You’ll see it in models such as the A5 and Q5. This level is aimed at drivers who want stronger acceleration without stepping into dedicated performance models.

What does 45 TFSI mean?

A 45 TFSI Audi usually produces roughly 245 to 265 bhp. It is often found in cars like the A5, Q5 and A7. This power band suits drivers who want quicker performance while staying within standard Audi model ranges.

What does 35 TDI mean?

A 35 TDI Audi is typically a 2.0-litre diesel producing around 150 to 163 bhp. It is one of the most common Audi diesel engines, known for strong low-speed pull and excellent motorway economy.

What does 50 TDI mean?

A 50 TDI badge usually refers to a 3.0-litre V6 diesel producing around 286 bhp. It is used in larger models such as the A6, A7 and Q7 for effortless long-distance driving and towing.

What about Audi hybrid and electric engines?

Audi has updated its electrified naming for 2026:

• TFSI e is used for plug-in hybrid (PHEV) models.

• e-tron is used for fully electric Audis.

• The Even/Odd Rule: New EVs now use even model names (e.g., Q6 e-tron), while combustion/hybrids use odd names (e.g., Q5 TFSI e).

What about S and RS Audi models?

High-performance models such as the S3, RS5 and RS6 do not use the 30-70 number system. They use S or RS branding exclusively, as these represent the pinnacle of Audi performance.