This aftermarket modification enhances the engine displacement of the Jeep TJ’s 4.0-liter inline-six engine. It typically involves replacing the crankshaft, connecting rods, and pistons with components that have a longer stroke, thereby increasing the cylinder volume and overall engine capacity. For example, a standard 4.0-liter engine might be upgraded to a 4.5-liter or 4.6-liter configuration via these components.
The increased displacement leads to several potential performance gains. These include enhanced low-end torque, improved throttle response, and a broader powerband. Historically, enthusiasts seeking more power from their Jeep TJ’s engine, particularly for off-road applications or towing, have employed this modification. The upgrade can provide a noticeable boost in performance without requiring significant alterations to other engine components, although supporting modifications are often recommended.