Nissan 240SX Performance Modification/Engine Swaps
Engine swaps are one way that Nissan 240SX owners increase the power of their vehicles. Swapping in engines from Japanese market vehicles such as the 180SX, Silvia, and Skyline can be both rewarding and frustrating. Less common engine swaps like VQ series engines (from the US Market 350Z and Maxima) and Domestic V8's have also been done.
Sourcing An Engine
JDM Engine swaps can be purchased from several sources in the United states. JDM Engine swaps usually are available in 2 forms.
A motorset usually includes everything you need to get it into your chassis, however, it is usually shipped as a mass of parts that might be a bit confusing for a novice mechanic.
A front clip consists of the entire front portion of a car, cut behind the dashboard and shipped from Japan complete. Clips are a bit easier for novice mechanics to make sense of because they can see where every part belongs before they install them on their own cars. As an added bonus, clips might sometimes include aftermarket parts or JDM body parts. the downside of clips is that they usually cost more to purchase and ship than motorsets.
No JDM engine swaps are legal for on-road use in US passenger vehicles, however, many owners drive vehicles with JDM engines with little or no risk of trouble. California 240SX owners have many additional inspection requirements that make owning a 240SX with a JDM engine swap a bit more of a hassle than other states.
In some circumstances, USDM (sold in the united states) engine swaps are legal, as long as the engine is newer than the chassis it is installed in and the new engine retains all of the smog equipment it came with from the factory.
For 1995 and newer 240sx's this includes the fully functioning OBDII system.
Check with your state and county emissions regulation authorities for specifics on required pollution control equipment and testing procedures.