Unlocking the Secrets of Subaru Engineering: How Much Does a Subaru Shortblock Really Weigh?

If you’re a Subaru owner, you may be interested in learning more about the technical aspects of your car engine, specifically the weight of the shortblock. The shortblock is a crucial component of the engine, and its weight can affect the overall performance and handling of the car. In this article, we’ll dive into the specifics of a Subaru shortblock’s weight, what it means for your car, and how different types of shortblocks can alter this weight.

What is a shortblock?

To understand the weight of a shortblock, it’s important to know what it is and how it functions in the engine. The shortblock is essentially the bottom half of the engine, consisting of the block, crank, connecting rods, and pistons. It’s called a shortblock because it does not include the cylinder head or any other components that attach to it. The shortblock plays a crucial role in the engine’s performance, as it houses the cylinders and pistons that help to generate power for the car.

How much does a Subaru shortblock weigh?

The weight of a Subaru shortblock can vary depending on the specific model and engine type. On average, a stock EJ series shortblock (which is used in many popular Subaru models such as the WRX and STI) weighs approximately 150 pounds. This weight can fluctuate slightly depending on the year and model of the car, as well as any modifications or upgrades that have been made to the engine.

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It’s worth noting that the weight of the shortblock is just one aspect of the engine’s overall weight. Other components, such as the cylinder head, exhaust system, and turbocharger, can also impact the weight of the engine. However, the shortblock is a key component that contributes significantly to the car’s overall weight and balance.

Why does shortblock weight matter?

The weight of the shortblock can have a significant impact on the car’s performance and handling. A heavier shortblock can affect the car’s center of gravity, making it more difficult to handle and maneuver on the road. It can also impact the car’s acceleration and braking capabilities, as the engine will need to work harder to maintain speed or come to a stop. However, a lighter shortblock can improve the car’s handling and balance, making it more responsive and agile on the road.

Aftermarket shortblocks: How do they differ?

Many Subaru enthusiasts opt to upgrade their shortblock with an aftermarket option, which can offer improved performance and durability. One popular option is the closed-deck shortblock, which features a more robust structure that can withstand higher levels of boost and horsepower. Another option is the semi-closed deck shortblock, which is more lightweight and offers improved heat dissipation.

Aftermarket shortblocks can significantly alter the weight of the engine, depending on the specific type and manufacturer. For example, a built closed-deck shortblock can weigh significantly more than a stock shortblock, as it includes additional reinforcements and materials. However, some aftermarket shortblock manufacturers may also offer lightweight options that can help to reduce the engine’s overall weight while still providing improved performance.

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Q: Can I reduce the weight of my Subaru shortblock?
A: Yes, there are some lightweight shortblock options available through aftermarket manufacturers. However, it’s important to ensure that the shortblock you choose is compatible with your specific car model and engine.

Q: How does shortblock weight affect acceleration?
A: A heavier shortblock can make it more difficult for the car to accelerate quickly, as the engine is working harder to generate power. A lighter shortblock can help to improve acceleration and overall performance.

Q: Do all Subaru models use the same shortblock weight?
A: No, the weight of the shortblock can vary depending on the specific model and engine type. However, many popular Subaru models such as the WRX and STI use the same EJ series shortblock, which is approximately 150 pounds.


Overall, the weight of the shortblock is a crucial aspect of a Subaru engine’s performance and handling. While a heavier shortblock can impact the car’s balance and responsiveness, a well-designed lightweight aftermarket shortblock can provide improved performance without sacrificing durability. If you’re considering upgrading your Subaru engine, it’s important to do your research and choose the shortblock that’s best suited for your driving needs and preferences.

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Joseph Weaver

With a background in engineering and a passion for cars, Joseph brings a unique perspective to our blog. He's particularly interested in the technology and innovation behind Subaru's advanced safety features, and his articles on this topic are always insightful and informative. When he's not writing, he enjoys playing video games and spending time with his family.

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