Renault GT Turbo Engine Explained

The Renault GT Turbo, a name that still evokes a smile among hot hatch enthusiasts, burst onto the scene in 1985 as a potent and engaging performance variant of the popular Renault 5. At its core, powering this spirited machine, was a fascinating piece of engineering – a heavily modified version of the venerable Cléon engine. While its roots might trace back to earlier designs, Renault's engineers worked their magic to transform this compact unit into a truly exhilarating powerplant, especially with the addition of a turbocharger. Let's delve into the specifics of what made the GT Turbo's engine so special and how it contributed to its legendary status.

The Cléon Engine: A Robust Foundation

The engine chosen for the GT Turbo was based on Renault's Cléon engine family. The original Cléon engine, first introduced in 1962, was a robust and relatively simple pushrod, four-cylinder unit. In its initial form, it displaced 1,108 cc. However, for the GT Turbo, Renault engineers significantly increased the displacement to 1,397 cc (often referred to as 1.4 litres). This larger displacement provided a solid base for the performance modifications that were to follow.

The Cléon engine's design, while not cutting-edge by 1985 standards, was known for its durability and ease of maintenance. Its pushrod valve actuation, a design predating overhead camshafts, meant a simpler, albeit less efficient, valvetrain. However, for a performance application, especially one aiming for accessible power, it proved to be a more than capable foundation.

Turbocharging: The Game Changer

The defining characteristic of the GT Turbo's engine was, undoubtedly, its turbocharger. Renault opted for an air-cooled Garrett T2 turbocharger. The T2 was a relatively compact and responsive turbocharger, well-suited to the 1.4-litre engine. Turbocharging dramatically increased the engine's power output, transforming the relatively modest naturally aspirated Cléon into a feisty performer.

The addition of the turbocharger meant that the engine management and fueling systems had to be significantly re-engineered. This included changes to the carburetion (often a twin-choke Weber or Solex carburettor) and ignition timing to cope with the increased boost pressure and combustion temperatures. The goal was to deliver a noticeable surge of power when the turbo spooled up, providing that characteristic burst of acceleration that defined the hot hatch experience of the era.

Engine Specifications: A Closer Look

Here's a breakdown of the key specifications of the Renault GT Turbo's engine:

Performance and Driving Experience

The combination of the 1.4-litre turbocharged Cléon engine and the lightweight chassis of the Renault 5 created a car that was renowned for its agility and punchy performance. The GT Turbo offered a driving experience that was raw, engaging, and often described as 'characterful'. The turbo lag, a common trait of turbocharged engines from this period, was present, meaning there was a noticeable delay between pressing the accelerator and feeling the full force of the turbocharger kick in. However, once on boost, the GT Turbo delivered strong acceleration, making it a formidable competitor in its class.

The engine's torque band was typically focused in the mid-range, encouraging drivers to keep the revs up to stay in the power band. This, combined with the car's nimble handling, made for an exciting driving experience, particularly on twisty roads. The distinctive sound of the turbocharged engine, often accompanied by the whistle of the turbocharger, further added to its appeal.

Modifications and Evolution

Throughout its production run, the GT Turbo received minor updates and variations, often tailored to specific markets. Some versions might have featured slightly different boost pressures or carburettor setups, leading to minor variations in power output. The engine's robust nature also made it a popular choice for tuning and modification. Enthusiasts often sought to increase boost pressure, upgrade the intercooler, or improve the fuel delivery to extract even more power from the already potent powerplant. These modifications, while potentially pushing the limits of the original design, further cemented the GT Turbo's reputation as a capable performance car.

Common Questions About the GT Turbo Engine

What is the displacement of the Renault GT Turbo engine?

The Renault GT Turbo uses a 1,397 cc (1.4 litre) engine.

What type of turbocharger does the GT Turbo have?

It is equipped with an air-cooled Garrett T2 turbocharger.

Is the GT Turbo engine a pushrod design?

Yes, the Cléon engine used in the GT Turbo is a pushrod unit.

What was the approximate power output of the GT Turbo engine?

The power output was typically around 115-120 bhp, depending on the market and specific model.

Conclusion

The engine of the Renault GT Turbo was a masterclass in making the most of a proven design. By taking the sturdy Cléon engine and equipping it with a Garrett T2 turbocharger, Renault created a compact powerhouse that delivered exhilarating performance. The 1.4-litre turbocharged engine, with its characteristic surge of power and engaging driving dynamics, was central to the GT Turbo's success and its enduring legacy as one of the most exciting hot hatches of the 1980s. It stands as a testament to how clever engineering can transform a humble powerplant into something truly special.