Subaru FA24D 2.4L Engine Specs, Problems, Reliability, Info

Subaru 2.4L FA24 Overview

The FA24D is the latest naturally aspirated four-cylinder boxer engine from the FA family, which replaced the 2.0-liter FA20D in the 2022+ Subaru BRZ and Toyota GR86 models. As its predecessor, the FA24 utilizes the combined fuel injection system D-4S (port + direct injection) provided by Toyota. But besides the larger engine capacity, there are other notable changes. Let's see what's new here.

FA24D Engine Design

The architecture of the engine block has remained the same: an open-deck aluminum cylinder block with cast-in iron cylinder liners. The piston stroke didn’t change, but the cylinder bore was increased from 86 mm (3.39 in) to 94 mm (3.70 in). This block was fitted with new connecting rods and pistons. The previous FA20 engines had so-called diagonally split, asymmetrical connecting rods. The FA24, on the other hand, has beefier and stronger EJ-style connecting rods (they are split horizontally) that are the same weight. New pistons have a larger diameter, but weigh only 60 grams more.

The engine kept aluminum DOHC heads with dual AVCS system. Of course, they were updated to accommodate a larger flow. The valve covers now made from plastic. The FA24 has a new intake manifold with shorter but larger diameter runners. It is also lower than that of the previous model. The engine still uses Toyota D-4S combined fuel injection system, but the direct fuel injection pressure is 20MPa, the same as the previous FA20DIT turbo engine had. In addition, an oil cooler has been added to the engine.

What's the End Result?

The FA24 model has a larger capacity, but the engine's dimensions and weight have remained almost unchanged. At the same time, the increased displacement has allowed for a significant improvement in both power and torque. This NA boxer engine delivers 228-234 hp at 7,000 rpm and nearly 185 lb-ft (250 Nm) of torque at 3,700 rpm, which are pretty good numbers for the BRZ considering the weight of the vehicle.

Engine Specs

FA24D Problems and Reliability

The FA24D is a new engine on the market, and so far, there is no evidence of any serious faults. However, there are some topics that deserve our attention.

• Some owners have reported oil starvation problems, which mostly occur on racetracks.
• Many people don't like the sound of FA engines. They say FA24D sounds like a diesel tractor or a sewing machine. The "tick-tick" noise is produced by the DI injectors and the high-pressure fuel pump.
• The D-4S system keeps the intake and valves clean better than DI alone. But carbon build-up still occurs.
• The FA24 engine does not have hydraulic lifters, so you may need to adjust the valves from time to time.

Summary

Well, this is a high-performance, sport car engine that runs at its limits. The FA24D requires proper and regular maintenance, as well as high-quality motor oil and premium gas. The average life of the FA24 engine is about 150,000 miles (250,000 km). But keep in mind, racing tracks significantly shorten the lifespan of the engine.