Do Twin-Turbo Engines Require Premium Gas? Here's Which Rating Toyota Recommends

Whether or not twin-turbo engines require premium gas is a matter for each individual engine manufacturer to decide. Reviewing some carmakers' statements as to which grade of fuel they recommend for their twin-turbo engines will provide a general sense of guidance, but you should always follow the advice provided by the manufacturer of your specific vehicle when you pull up to the pump. What this means is that you will find the information you need by consulting what is widely considered to be the least-read book in the world — your vehicle's owner's manual. Follow the guidance provided there, and you should be fine.

Have you ever wondered what happens if you put regular gas in a premium car? While there are many twin-turbo vehicles that may recommend premium fuel of 91 to 93 octane (also known in the U.S. as AKI, or anti-knock index) for your twin-turbo engine so that it can provide optimal performance, today's computer controls may also allow your engine to safely adjust and run on lower octane fuel with less peak horsepower output. Again, your owner's manual will tell you whether this is possible. By following your manual's advice, you should be able to avoid costly engine damage that could result from using a non-specified fuel grade. It's better to be safe than sorry.

Toyota produces a twin-turbo engine, the i-Force V6, which is available in Toyota's Tundra full-size pickup truck as a replacement for its previous V8 engine. Our review of the Tundra found it to be practical but thirsty. In the 2025 Toyota Tundra, the twin-turbo i-Force V6 comes in three different versions, all of which have a 3.4-liter displacement.

The entry-level version produces 348 horsepower, the mid-level version puts out 389 horsepower, and the version with the maximum output is the i-Force Max gasoline-electric hybrid system that provides a total system output of 437 horsepower, along with a massive 583 lb-ft of torque. This likely makes the i-Force Max the best choice for towing or hauling heavy loads. In 2022, the i-Force Max powertrain in the Tundra received a Wards 10 Best Engines & Propulsion Systems award.

Fuel recommendations for the i-Force and i-Force Max engines state that you should only use unleaded gasoline of 87 octane or higher with these engines. This is equivalent to regular gasoline for any of these engines. However, Toyota has come out with a performance upgrade called the TRD Performance Package. This upgrade starts with the 389-horsepower version of the non-hybrid i-Force V6. Using a combination of more airflow going into the turbos, improved engine calibration software, and a cat-back exhaust system, the i-Force gets a boost to 421 horsepower. On Tundras with the i-Force Max hybrid powertrain, power goes from 437 to 469 horsepower. The TRD Performance Package does require 91 octane premium fuel.