* Audi A4 1.8T (B6): This model had a 1.8 liter turbocharged four-cylinder engine.
* Audi A4 2.0T (B6): This model had a 2.0 liter turbocharged four-cylinder engine (available in some markets).
* Audi A4 3.0 (B6): This model had a 3.0 liter V6 engine.
* Audi A4 3.2 (B6): This model had a 3.2 liter V6 engine.
* Audi A4 Quattro (B6): This model was available with either a 1.8T or a 3.0 V6 engine, and offered all-wheel drive.
To determine the exact base engine size of your specific 2005 Audi A4, you can refer to the vehicle's VIN number or the owner's manual.
