Is A 1.5-liter Firefly Engine (GSE) In The Works?

Evaluating The Rumors From Around The Web...

FCA Italy powertrain team presented a new generation of turbocharged engines during this year’s Vienna Motor Symposium.

These engines, known collectively as the Global Small Engine (GSE) family, were presented in 1.0-liter 3-cylinder and 1.3-liter 4-cylinder variants. Both engines feature the highly innovative MultiAir III technology, providing a much wider operation and better response compared to the last generation of MultiAir technology.

1.3-liter Turbo “T4” GSE Engine. (FCA)

By implementing specific intake and exhaust cam profiles, low-load efficiency is improved by recirculating the exhaust gas by opening the intake valves in advance, while the high-load output is improved at the same time by delaying the intake valve closing. In other words, MultiAir III technology can reduce the real compression ratio, controlling knock and substantially improving fuel efficiency when the engine is delivering high power.

They also announced the development of a twin-scroll turbo version of these engines. Of course, a twin-scroll turbo can be applied only on engines with an even number of cylinders, which leaves only the 4-cylinder variant of GSE as the possible application for this technology.

1.3-liter Turbo “T4” GSE Engine. (FCA)

However, currently, there is no twin-scroll turbocharger for an engine that is smaller than 1.5-liters in capacity. A twin-scroll turbocharger is an ideal choice for a turbocharger on an engine of this size because it offers better responsiveness at lower RPMs.


Lately, we’ve heard some whispers about 1.5-liter GSE under development for Alfa Romeo. This engine could be extremely important for the European market where Giulia’s competitors like Mercedes Benz C-class, Audi A4, and BMW 3 Series all offer 1.5-liter gasoline engines. Making this engine even more important is the eventual demise of the diesel engine in Europe.

Engines in the GSE family are very compact. They have 77mm bore spacing and 70mm bore. That’s pushing the limits for what is possible on an HPDC engine block with steel liners. Currently, 71mm bore is the biggest they can achieve with steel liners, so this rumored 1.5-liter engine would have a very long stroke of 94.5mm or 97mm to achieve 1.5-liters of capacity.

1.3-liter Turbo “T4” GSE Engine. (FCA)

We don’t know if the company will seek power or efficiency out of a potential 1.5-liter GSE powerplant. Currently, both GSE and GME in their most powerful versions have power around 135-140 HP per liter and torque numbers around 205 Nm (151 lb-ft) per liter. A 1.5-liter GSE could very likely have around 205 HP and a 310 Nm (229 lb-ft) of torque.


One competitor is offering a belt-driven mild hybrid system with their 1.5-liter gasoline engine. Alfa will likely produce a similar solution. Belt-driven mild hybrids are in the Alfa Romeo 5 year plan, so this engine could benefit from that technology, currently known as eTorque on the Jeep Wrangler JL equipped with the 2.0-liter turbo and the 3.6-liter Pentastar V6 2019 Ram 1500.

1.3-liter Turbo “T4” GSE Engine. (FCA)

A lot remains in question about this engine, but the benefits it would provide Alfa Romeo are numerous. It will allow Alfa to better compete with German luxury brands that already offer similar engines. Stay tuned to Mopar Insiders for more information on this engine.


Bili is a 32-year-old long-time Fiat and Alfa Romeo fan who always had a fond of Jeep® and Chrysler. He is an IT engineer from Europe. His hobby is cycling but you can ask me almost anything about the sport, well at least those sports which are popular in Continental Europe. He is also a huge motorsport fan which includes Indycar.

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