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Nissan 240SX / 200SX / 180SX S13 / S14
Power hp
Torque Nm
Displacement L
Layout
Swap overview with verified parts, part numbers and sources.
RB25DET in Nissan S13/S14.
Documented from 12 recorded sources: 3 of the ten mandatory blocks are carried by two independent publishers, 3 remain open, 1 does not apply. Internal confidence 66%.
(1Q) RB25DET: 2,498 cc inline six, turbocharged, with 250 hp and 235 lb-ft quoted for Series 1 and 276 hp and 267 lb-ft for the NEO. The three generations differ substantially and not cosmetically. Series 1 from 1993 has reinforced connecting rods, a 45V1 turbocharger, NVCS variable timing on the intake and 370 cc/min injectors. Series 2 from 1995 revises the electrical system, uses a ceramic rather than aluminium turbine wheel, integrates the ignition coil igniters and changes the airflow meter, ECU and cam angle sensor shaft. The NEO from 1998 uses solid rather than hydraulic lifters, revised camshafts with a solenoid-controlled VCT, a smaller combustion chamber, GT-R specification connecting rods, a higher 9.0:1 compression ratio, the larger OP6 turbo with steel wheels and a reduced intake runner diameter of 45 mm instead of 50 mm. Bore and stroke are not stated on the page opened and are therefore not reproduced here. No figures for the RB26DETT were obtained in this run.
Status: SINGLE_SOURCE · Confidence 50%
Both engines are turbocharged from the factory: RB25DET single turbo, RB26DETT twin turbo. No naturally aspirated variant is commissioned here.
Buy the donor as an engine-and-gearbox package and decide the series before buying, because the harness follows the series. For RB25DET the practical split is non-NEO (Series 1 and Series 2, roughly 1993-1998) against NEO (from 1998, R34). One harness supplier sells separate part numbers for the two and describes its standard S13 harness as covering Series 1 or Series 2 from 1994-1998 Skyline GTS/GTS-T and Stagea, explicitly not addressing NEO on that page. For RB26DETT the donor is an R32, R33 or R34 GT-R, and the donor's own oil pan is the one part that must NOT simply be carried over. Take from the donor at minimum the engine, gearbox with bellhousing, ECU, engine loom, turbo and manifolds, and the crank pulley, power steering bracket and pump and fan clutch, which one build thread names as parts that have to come from the correct Nissan units for the cooling system to work.
Plan the purchase in four packages. Engine package: engine, turbo and manifolds, ECU and engine loom, plus the crank pulley, power steering bracket and pump and fan clutch. Gearbox package: the gearbox with its bellhousing, and for an RB26 either the R32/R33 RB26DETT bellhousing with a Z32 transmission or an RB25DET five-speed as the direct alternative. Chassis package bought new rather than from the donor: mount kit, driveshaft matched to the recipient's ABS or non-ABS differential, and a harness matched to the engine series. Oil pan: for RB25DET the rear-wheel-drive RB25 pan; for RB26DETT either a modified RB26 pan or an RB25 rear-wheel-drive pan. Budget indication from the sources opened, all prices as of 01.08.2026 and all from US suppliers: mounts USD 412.50 or USD 473.00, driveshaft USD 489.50 in steel or USD 649.00 in aluminium, harness from USD 785.00, or from USD 599.00 for a basic engine and transmission harness quoted in a build thread.
Status: SUPPORTED · Confidence 70%
Two mutually independent suppliers sell mount kits for exactly this chassis and engine family, and they solve the job differently. ISR Performance supplies left and right motor mounts, a rubber transmission mount, two front crossmember mounts, a transmission brace and hardware, at USD 412.50, price as of 01.08.2026, stating that the kit works with RB20, RB25 and RB26 and that its mounts fit both S13 and S14 so parts can be moved between chassis. The gearbox must be specified when ordering, RB20 or RB25, and the kit is for rear-wheel-drive transmissions. CXRacing supplies engine and transmission mounts only, in 6 mm stainless steel with polyurethane bushings and slotted holes that allow the engine to be moved forward and backward by 1 to 1.5 inches, at USD 473.00, price as of 01.08.2026, and states plainly that many other parts are also needed to complete the swap. A build guide adds the fitting sequence: the engine mount adapter plates go on the crossmember loose, the assembly is aligned with a jack under the transmission and under the oil pan, and the crossmember bolts are then tightened to 51-58 ft lb and the transmission mount to 16-21 ft lb.
This is the single most important finding of the record and it is where the two commissioned engines part company. For the RB25DET the requirement is stated by the mount supplier without qualification: you must use a rear-wheel-drive RB25DET oil pan for proper pan clearance, and the all-wheel-drive RB26 pan will not fit. For the RB26DETT that leaves two documented routes and both are work: either modify the RB26 aluminium pan by cutting off the front differential section, welding it closed and grinding down the webbing for crossmember clearance, which one builder recommends because the aluminium casting is better than the stamped steel alternative, or fit a rear-wheel-drive RB25DET pan instead. In either case the pickup must match the pan actually used. Nobody in this run states a pickup part number, and no measurement of the resulting ground clearance was found.
For the RB25DET the gearbox that comes with the engine is the one used: the mount suppliers require the gearbox to be specified when ordering, RB20 or RB25, and both build for rear-wheel-drive transmissions. For the RB26DETT two routes are documented and both avoid the GT-R's own all-wheel-drive gearbox: use the R32 or R33 RB26DETT bellhousing, which is stated to bolt directly to the Z32 transmission, or fit an RB25DET five-speed as a direct bolt-on alternative. A build report adds the fitting detail: the transmission is raised until the shifter cover is level with the tunnel, the mount is bolted to the chassis loose, the gearbox is then pried toward the passenger side and the mount tightened to 16-21 ft lb.
The mount kits cover this: one supplier includes a rubber transmission mount and a transmission brace in the kit, the other includes a transmission mount. A build report specifies the fitting sequence and a torque of 16-21 ft lb at the chassis, and records that the transmission is pushed toward the passenger side before final tightening.
Status: SUPPORTED · Confidence 72%
(1Q) One build report records that the original KA shifter bushing at the end of the shifter still works but is much smaller than the RB item, which leaves extra play at the lever, and that the gearbox is positioned so the shifter cover sits level with the tunnel. Nothing was found on tunnel cutting, on lever position in the S14 as opposed to the S13, or on a purpose-made bushing.
Status: SINGLE_SOURCE · Confidence 40%
No reliable combination-specific information found on clutch, flywheel and release system for this combination. Searched: 'RB25DET 240SX swap gearbox bellhousing clutch'. A build report mentions only that the clutch reservoir is filled with brake fluid and bled after installation, which is a commissioning step and not a specification.
Status: OPEN
No combination-specific automatic transmission solution documented. Both mount suppliers build for manual transmissions only and one states the manual requirement in its product options; no automatic route for either engine in this chassis appeared in any of the eight search runs.
Status: NOT_APPLICABLE
No combination-specific automatic transmission solution documented.
Status: NOT_APPLICABLE
No combination-specific automatic transmission solution documented.
Status: NOT_APPLICABLE
No combination-specific automatic transmission solution documented.
Status: NOT_APPLICABLE
No combination-specific automatic transmission solution documented.
Status: NOT_APPLICABLE
A purpose-made driveshaft is the normal solution and it is chassis- and differential-specific, not engine-specific alone. One supplier lists a one-piece steel shaft with Dana/Spicer heavy-duty universal joints for the S13 with RB25DET five-speed at USD 489.50, with an aluminium version at USD 649.00, and sells separate ABS and non-ABS versions because the differential determines the length; the same range exists for the S14. A build report names a McKinney Motorsports driveshaft for the same job. No length figure is published on either page, so the shaft must be ordered against the actual differential fitted, not against the engine.
(1Q) One finding is concrete and it is a buying trap rather than a specification: the driveshaft length depends on which differential the car has, and one supplier sells separate ABS and non-ABS driveshafts for the S13 with the RB25DET five-speed for exactly that reason, stating that the change in differential changes the length of the driveshaft and that buyers must verify which differential their car has before ordering. Nothing was found on ratios, on load capacity against the torque of either engine, or on whether a stronger unit is advisable.
Status: SINGLE_SOURCE · Confidence 44%
(1Q) One build report documents a Walbro fuel pump replacing the original, noting that the replacement is actually smaller than stock, together with an adjustable NISMO fuel pressure regulator, and describes the pump as sitting in a relocated battery kit in the boot. No pressure figure, no flow figure and no injector specification for this combination were obtained. Given that both commissioned engines are turbocharged and that stock injector sizing differs between RB25 series, treat fuel delivery as unresolved and measure pressure and delivery under load before road use.
Status: SINGLE_SOURCE · Confidence 40%
Two publishers touch cooling and they point in opposite directions, which is worth recording rather than averaging. One build report removes the original radiator and air conditioning condenser and fits twin 12-inch electric pusher fans to the new radiator. A second thread states the opposite emphasis: cooling requires specific OEM Nissan parts, naming the crank pulley, the power steering bracket and pump and the fan clutch, and says electric fans alone are not necessary. Both are talking about the same engine in the same chassis. What follows for a builder is not which is right but that the mechanical fan drive and its ancillaries are a decision to be made deliberately, and that the ancillary bracketry has to match whichever route is chosen. No radiator part number, no core size and no measured coolant temperature was found.
No reliable combination-specific information found on intercooler and charge piping for this combination. Searched: 'RB25DET 240SX swap exhaust manifold downpipe fuel pump injectors', 'RB25DET swap 240SX radiator cooling clearance'. Both engines are factory turbocharged and therefore need a charge air route, but no source opened in this run states which cooler, which piping or what clearance is available in front of the S13 or S14 radiator support.
(1Q) One build report documents a 3-inch downpipe and test pipe joined to the exhaust system at the catalytic converter position. That is a competition arrangement, not a road one: a test pipe replaces the catalyst. Nothing was found on a road-legal manifold and downpipe route, on catalyst position, on lambda sensor placement, or on silencer clearance in either chassis. For a German build this field is effectively empty, because the one documented solution is the one that cannot be registered.
Two documented routes, both with concrete detail. Route one is a bought harness: one specialist supplies a one-piece tucked main engine and transmission harness for the RB25DET Series 1 or Series 2 in the S13 at USD 785.00, price as of 01.08.2026, covering the alternator charge cable, six coilpack and six injector connections, knock sensors, MAFS, throttle position, boost solenoid, VTC, cam and crank sensors, idle, oxygen sensors, grounds and the ECU diagnostic connector. Three integration points are stated explicitly: factory tachometer use requires the DOHC 240SX gauge of 1991-1994 on 1989-1990 SOHC cars, with manual adjustment by potentiometer if the cylinder count changes; the speedometer requires the original factory speed sensor fitted in the new transmission; and the customer must still supply the battery cables from the positive terminal to starter and fusebox. The same supplier sells separate part numbers for NEO engines. Route two is hand-adapting the donor loom to the recipient's, for which one build guide gives the actual circuits at the RB white main plug B-82: start switch orange to grey/red, ignition relay red, injector control black/red from the KA side, fuel pump relay black/pink, check engine light red/white, tachometer yellow/lavender, speedometer yellow/green, plus a main battery ground from the RB block to the chassis and the starter ground from the RB lower harness olive plug to the KA black/yellow at the fusebox.
(1Q) On instruments there is concrete information and on the immobiliser there is none. Instruments: factory tachometer operation requires the DOHC 240SX gauge of 1991-1994 when the recipient is a 1989-1990 SOHC car, and the tachometer needs manual potentiometer adjustment if the cylinder count changes; the speedometer needs the original factory speed sensor fitted into the replacement transmission; the harness includes the cluster coolant temperature switch connector and factory warning lights remain functional. One build report records the practical failure mode: the aftermarket display used was in km/h and completely inaccurate, and the retained factory electronic speedometer read about 10 mph out. Immobiliser: neither the harness supplier's page nor the build guide mentions immobiliser handling at all. For a European car this is the gap that matters most, because the recipient here is not necessarily a North American KA car.
Status: SINGLE_SOURCE · Confidence 46%
No reliable combination-specific information found on what this conversion requires of brakes or suspension. Searched: 'RB25DET 240SX swap differential driveshaft brakes suspension requirements'. The search returned driveshafts and differentials but nothing on braking. What is on record from the German regulatory side and belongs in the planning rather than in this field: an inspection organisation states that if engine output is increased, the brakes may have to be uprated and the suspension adapted to the changed performance. Against a KA24DE or a CA18DET that is a substantial increase, so expect the question to be asked.
Status: OPEN
Six documented points, from two independent publishers, and the first four are the ones that decide whether the car goes together at all. Chassis-side, from the build accounts: the firewall has to be indented by 1 to 1.5 inches, and the author records his own mistake in doing it at the wrong place, at the starter, when the bump that actually needs indenting is at seven o'clock from there; a second account puts the same job as indenting the transmission tunnel about a quarter of an inch just behind the starter. Clearance between the steering shaft and the oxygen sensor housing must be inspected and is quoted at 3/32 to 1/4 inch, and if there is not enough, the transmission bolt holes may need to be slotted. Instrument accuracy is a recorded failure: the aftermarket display read in km/h and was completely inaccurate, and the retained factory electronic speedometer was about 10 mph out. Shifter play increases because the retained KA bushing is much smaller than the RB item. Engine-side, from the engine literature: oil surge in the cylinder head under track use, premature turbo failure above 0.9 bar on the standard turbocharger, ignition coils that fail and are recommended for replacement every 60,000 miles, cam angle sensor trouble, and elevated oil temperatures under hard driving. No abandoned or reversed conversion is reported in this run.
Status: SUPPORTED · Confidence 78%
No reliable combination-specific information found on any actually completed German approval of an RB25DET or RB26DETT in an S13 or S14. Searched: 'RB25DET Umbau 200SX S13 S14 Deutschland TUEV Eintragung', 'Nissan 200SX Motorumbau Einzelabnahme Paragraf 21 StVZO'. Both German-language findings that appeared were unreachable: a Swiss build page could not be retrieved because its robots.txt did not resolve, and a German forum article answered with HTTP 404. One finding weighs directly against feasibility and is not from the scene but from a supplier: the mount kit that is the most commonly cited hardware for this swap carries the notice that it is legal only for use in competition vehicles which may never be registered, licensed or used on public streets or highways. A part sold under that restriction is a poor starting point for a German registration, and an engineer will read the same notice.
Status: SINGLE_SOURCE · Confidence 38%
Germany, as of 01.08.2026. Two procedures can apply here and a JDM-donor build often meets both at once. First the conversion itself: TUV SUD states that the operating permit (Betriebserlaubnis) may lapse where modifications 'may be expected to endanger other road users, change the vehicle category, or worsen emissions or noise behaviour', and adds the consequential requirement in plain terms: 'If engine output is increased, the brakes may have to be uprated and the suspension adapted to the changed performance.' Against a KA24DE or a CA18DET, both commissioned engines represent a substantial increase, so that requirement is to be expected rather than hoped away. Second the origin: a German source on individual approval (Einzelabnahme) under § 21 StVZO lists what the data sheet of such an inspection covers - 'Abgasgutachten, lichttechnisches Gutachten, elektromagnetische Vertraeglichkeit, Bremsgutachten, Geraeuschgutachten, Leistung, Hoechstgeschwindigkeit, Masse, Gewichte, Bereifung und Anhaengelasten' - and states that a full inspection is mandatory for exactly two groups, one of them 'Einzelimporte aus dem Nicht-EG-Raum', naming Japan expressly. Since the donor engines are JDM and many donor shells are too, that is not a theoretical remark. THE CRITICAL POINT, and it is a hardware one rather than a legal one: the mount kit most commonly used for this swap is sold with the notice that it is legal only for competition vehicles which may never be registered, licensed or used on public streets or highways. The only documented exhaust arrangement found in this run uses a test pipe in place of the catalyst. Both of those point away from a road registration, and neither can be argued past an engineer. Nothing was found on the emissions classification of either engine in this chassis or on the resulting key numbers. No completed German approval of this combination was found. This is orientation and does not replace advice from the competent inspection body; agree the evidence plan in writing before buying parts.
Status: SUPPORTED · Confidence 62%
All prices as of 01.08.2026, all from opened pages, all US or international retail without German duty or import VAT. ISR Performance - RB swap mounts for S13/S14, left and right motor mounts, rubber transmission mount, two front crossmember mounts, transmission brace and hardware, RB20/RB25/RB26, gearbox to be specified when ordering, USD 412.50, sold with a competition-only notice: https://www.isrperformance.com/isr-performance-rb-swap-mounts-for-nissan-240sx-s13-14/ || CXRacing - engine and transmission mount kit RB20/RB25 for 89-99 S13/S14, 6 mm stainless steel with polyurethane bushings, slotted for 1 to 1.5 inches of fore and aft adjustment, USD 473.00: https://www.cxracing.com/ESK-RB-S13-KIT || ISR Performance - driveshaft RB25 swap S13 ABS, one-piece steel with Dana/Spicer universal joints, USD 489.50, aluminium version USD 649.00, separate non-ABS version: https://www.isrperformance.com/isr-performance-driveshaft-rb25-swap-s13-abs/ || Wiring Specialties - S13 240sx RB25DET swap wiring harness, Series 1 and Series 2 non-NEO, one-piece tucked main engine and transmission harness, from USD 785.00: https://www.wiringspecialties.com/240sx-s13-rb25det-wiring-harness/
No usable finding. No dedicated video search run was carried out and no video appeared as a result in the eight runs performed. Search terms for manual follow-up: 'RB25DET swap S13', 'RB26 swap 240SX', 'RB25 S14 build'.
No usable finding. No Instagram profile or post appeared in any of the eight search runs. Search terms for manual follow-up: 'rb25 s13', 'rb26 240sx', '#rbswap', '#rb25det'.
nicoclub.com - How To: RB25DET swap into a Nissan 240sx S13 (step-by-step with torque figures and ECU pin colours; read the author's own disclaimer): https://www.nicoclub.com/archives/rb25det-swap-into-240sx-s13.html | nicoclub.com - Rb26dett s13 swap questions (the AWD oil pan problem and the Z32 gearbox route): https://forums.nicoclub.com/rb26dett-s13-swap-questions-t588789.html | drifted.com - RB25DET engine guide, Series 1 / Series 2 / NEO differences and weak points: https://www.drifted.com/rb25det/ | tuvsud.com - Aenderungsabnahme nach Paragraf 19 StVZO: https://www.tuvsud.com/de-de/branchen/mobilitaet-und-automotive/tuning-eintragungen-und-aenderungsabnahmen | abgasdatenbank.com - Paragraf 21 StVZO, scope and import cases: https://abgasdatenbank.com/%C2%A721-stvzo/ | NOT REACHABLE, noted for follow-up: s-chassis.com 'RBs in S14s complete walkthrough' (HTTP 403): https://www.s-chassis.com/forums/engine-swaps-13/rbs-s14s-complete-walkthrough-37494/ | NOT REACHABLE: dudecars.ch 200SX S13 with RB25 conversion (robots.txt unresolvable) | NOT REACHABLE: nissanboard.de '200sx s13 mit RB25DET' (HTTP 404)
12 findings from 10 hosts, mapping to 10 publisher keys. 9 findings are reachable, 3 are not. 9 findings are used in substance and cited in fields. 8 search runs; every finding used was opened and read. Two findings are German-language and both are legal or technical framework sources, not combination-specific. Three notes on the counting. FIRST, the two genuine multiple entries: nicoclub.com supplies two findings, the RB25 build guide and the RB26 thread, and isrperformance.com supplies two, the mount kit and the driveshaft - each pair is ONE publisher. That matters most in the Cooling field, where both findings are nicoclub, and the status carries an explicit caution because of it. SECOND, the independent confirmations that do hold: engine mounts are carried by isrperformance.com and cxracing.com with structurally different products, the oil pan by isrperformance.com and nicoclub.com, the driveshaft by isrperformance.com and nicoclub.com naming two different manufacturers, the wiring by wiringspecialties.com and nicoclub.com, and the German legal framework by tuvsud.com and abgasdatenbank.com. THIRD, a source-quality caveat that is not visible from the URL: the author of the nicoclub RB25 build guide states in his own disclaimer that the content is compiled research from internet forums and that his mechanical experience is limited. Every figure taken from it - the torque values, the ECU pin colours, the firewall indent - is therefore carried as a build report and not as a manufacturer specification. Three findings remain uncited: s-chassis.com (HTTP 403), dudecars.ch (robots.txt unresolvable) and nissanboard.de (HTTP 404). The last two were the only German-language combination-specific findings located, which is why the German side of this record is empty.
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