twinturbo

Twinturbo refers to an automotive forced-induction configuration that uses two turbochargers to boost the intake air pressure of an internal combustion engine. The goal is to increase power output and, in some designs, improve throttle response across a broader RPM range. Twinturbo systems are often contrasted with single-turbo setups.

There are two common layouts. In parallel twin-turbo arrangements, both turbos operate simultaneously, each typically feeding a portion of the engine or two banks of cylinders. In sequential twin-turbo systems, a smaller turbo provides boost at low engine speeds to reduce lag, while a larger turbo kicks in at higher RPMs for greater boost. Air from the turbos is usually cooled by an intercooler to increase air density and efficiency. Boost regulation is achieved with wastegates and engine management systems.

Advantages of twinturbo designs include higher overall power and torque output for a given engine displacement, and in sequential configurations, improved responsiveness at lower RPMs. Disadvantages involve greater mechanical complexity, higher costs, increased heat and packaging challenges, and potentially higher maintenance requirements.

Notable applications include performance street cars and some race programs. Examples cited in automotive history include the Toyota Supra Mk4 with a sequential twin-turbo 2JZ-GTE engine, the Nissan GT-R (R35) with a twin-turbo V6, the Ferrari F40 with a twin-turbo V8, and the Porsche 959 with a twin-turbo flat-6. Related concepts include turbochargers in general, turbo lag, intercoolers, and the broader category of twincharged systems when combined with supercharging.