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What Are Stroker Kits, And How Do They Increase Torque?

An alternative to cylinder boring, a stroker kit is an effective but labour-intensive route to power gains

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What Are Stroker Kits, And How Do They Increase Torque? - Blog

Stroker kits include specially developed engine parts that lengthen the stroke of the piston within an engine’s cylinder, allowing it to travel further up and down each time. The lengthened piston stroke increases the amount of air and fuel forced into the cylinder, boosting the overall power of the combustion cycle and delivering more energy to the crankshaft, resulting in more torque delivered to the transmission and the vehicle’s wheels.

Venturing away from original manufacturer parts can cause some drawbacks. With a stroker kit installed, the piston has to travel further during its reciprocation, resulting in more stress placed on the cylinder, piston and the surrounding components. This means other aftermarket modifications may need to be introduced so that the rest of the powertrain can cope with the additional torque. An upgraded crankshaft will almost certainly need to be installed, as any consequential vibrations of an improperly fitted or weak crankshaft can become a serious issue for the rest of the powertrain.

The contents of a Titan Motorsport stroker kit for an R35 Nissan GTR
The contents of a Titan Motorsport stroker kit for an R35 Nissan GTR

Stroker kits result in more torque in the low rev range, but the engine’s ability to reach high revs will be hindered due to the increased travel in the piston’s movement, meaning a stroker kit can decrease the responsiveness of an engine. Some people avoid installing a stroker kit as it can interfere with the natural character of the powertrain, but the additional gains may be worth it if you’re looking for maximum power gains at the wheels.

A stroker kit is a relatively complex modification, so unless you’re an experienced home mechanic, we’d recommend consulting with a professional to install one. The engine will need to be disassembled, critical components replaced, and everything carefully reassembled, so it’s a big job. However, the power gains associated with a stroker kit are nothing to be sniffed at, so it may be worthwhile if you are looking to eke out every ounce of power from your car’s engine.

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Stroker kits tend to be more common for naturally aspirated engines, where extra capacity is one of the most reliable ways of making more power. In a turbocharged engine, increasing boost or fitting larger turbos is usually a cheaper way of making more power than fitting a stroker kit.

Have you ever thought about installing a stroker kit? If you have already installed a stroker kit, how much more power have you gained as a result? Comment with your experiences below.