SR20DET Swap Guide: Putting the Silvia's Heart Back in Your 240SX
The SR20DET into a 240SX is the most natural engine swap in the JDM world — you're putting the Silvia's engine back into the Silvia's chassis. Nissan sold the S13/S14 as the 240SX in America with the KA24 truck motor; Japan got the same car with a turbocharged heart. Here's what to know before you buy, from our Nissan floor in Dallas.
Red top, black top, notch top — what matters
S13 "red top": The early classic. Simple, cheap-ish once, now aging — condition matters more than color.
Late S13/S14 "black top / notch top": Revised head castings and, on S14/S15 engines, variable cam timing (VTC) on the intake — better midrange, better street engine.
S15 spec: The final and best iteration — improved turbo, strongest factory output, and the one everyone wants. Priced accordingly and worth it if you're keeping the car.
All are 2.0L iron-block turbo fours with a huge aftermarket. Between two engines of similar spec, buy the one with documented compression numbers and clear photos of the actual unit — a tired S15 is worse than a healthy black top.
Why the swap is (mostly) bolt-in
The 240SX and Silvia share a chassis, so SR20DET mounts, crossmember geometry and driveline are famously cooperative — this is a weekend-warrior-achievable swap with the right parts list: engine harness and ECU (buy the engine with them — sourcing later costs more), intercooler and piping, downpipe and exhaust, fuel pump upgrade, and the small stuff — clutch line adapter, gauges, radiator in good health for Texas heat.
Budget honestly
The engine set (engine, trans, harness, ECU) is the anchor purchase; plan roughly the same again for supporting parts and consumables if you're doing it right. Skimp on the intercooler, clutch or fuel system and the engine takes the blame for the install's shortcuts. Financing through Affirm is available on our engine sets if you'd rather spread it out.
KA24DE owners: the other path
No shame in the truck motor — a healthy JDM KA24 replacement keeps a drift missile alive for less. But if you're buying parts for boost anyway, the SR20DET is the cleaner total package: designed turbocharged from the factory, lighter, and worth more at resale.
Before you buy any SR20DET
Per-cylinder compression numbers in writing. Turbo shaft play checked. Photos of the exact unit — manifolds, turbo, harness, igniter visible. Confirmation of what ships: ECU, MAF, harness, accessories. Every SR we sell is auction-graded, compression-tested, and photographed as the engine on the pallet. Questions on spec differences for your build? Call/text (469) 570-4113 — we'd rather talk you out of the wrong engine than sell it to you.
JDM Alliance LLC · importing direct from Japan since 2013 · performance & swap engines · Dallas pickup, free crated freight nationwide, next-day to Houston, Austin, San Antonio and OKC.