Engine
Honda swaps

EF9 → ED9 B16A DOHC VTEC engine with Y1 cable-clutch gearbox Civic SiR (EF9) 1989-1991 → CRX (2nd gen (ED9)) 1988-1991 Complete working transplant documented on a 1988 ED9 with an EF9 front cut as the donor. Bolts up / fits: B16A high-pressure fuel line, heater-tap hose, fuel main and return lines, battery positive to starter. Required donor/other parts beyond the engine: EF8/EF9 cabin loom, PW0 OBD0 ECU, EF8/EF9 power steering high-pressure hose (carries a pressure switch), EF8/EF9 shift linkage and B-series shifter (the D-series linkage will not fit), EF8/EF9 clutch and accelerator cables (D16A8 cables do not match), DA6 driveshafts and mid shaft (EF8/EF9 shafts are too short), and the EF9 radiator (the ED9 radiator hose necks are too small; swap the fans between housings to keep the ED9 fan connectors). Recommended extras: EF8/EF9 front hubs and calipers, brake master cylinder. The A/C compressor fouls the front crossmember; an HAsport bracket allows the D-series compressor to be used and clear it. The conversion took the author four 6-hour days working alone, including stripping the front cut. Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ.

EM1 → EG B16A2 engine and hydraulic manual transmission Civic Si (EM1) 1999-2000 → Civic (EG) 1992-1995 Yes — the B16A2 engine and transmission from a 1999-2000 Civic Si (EM1) fits a 1992-1995 Civic (EG) with B-series engine mounts, B-series swap axles, a B-series shift linkage and an ECU/harness that matches the chassis. Hasport states its EGSTK mount kit works with the B16A2 and B16A3 (2-bolt left-hand bracket, hydraulic transmission) in the 92-95 Civic. The B16A2 is a 1.6 L DOHC VTEC rated at 160 hp in the US Civic Si. Axle and linkage parts are B-series specific because the transmission uses an intermediate shaft that the D-series EG did not have. Difficulty Moderate Modification required Fits VERIFIED ✓ MODS REQ. EG → EF D16Z6 SOHC VTEC engine and hydraulic transmission Civic Si (EG) 1992-1995 → Civic (EF) 1988-1991 Yes — the D16Z6 SOHC VTEC engine from a 1992-1995 Civic Si (EG) fits a 1988-1991 Civic (EF) with EF mounts for the 92+ D-series, a clutch solution for the hydraulic transmission and OBD0-to-OBD1 wiring work. Hasport says its EFDHC kit works with 92-00 Civic D-series hydraulic transmissions and lets the EF clutch cable operate them. Innovative sells a mount kit for 92+ D-series engines in the 88-91 Civic/CRX with a hydraulic transmission. The D16Z6 was rated at 125 hp and was also used in the 1992-1995 Civic EX and 1993-1995 del Sol Si. Difficulty Moderate Modification required Fits VERIFIED ✓ MODS REQ. CB → EK F22A engine with H-series manual transmission (F-swap) Accord (CB) 1990-1993 → Civic (EK) 1996-2000 Yes — an F-series engine such as the F22A from a 1990–1993 Honda Accord (CB) fits a 1996–2000 Honda Civic (EK) when it is paired with an H-series manual transmission and an EK H/F-series mount kit. Hasport says its EKH3 kit works with 90–93 F-series engines and some F-series DOHC engines. Innovative Mounts says its 96–00 Civic F/H-series kit works for F-series conversions using an H-series transmission, needs a 92–96 Prelude rear T-bracket, and that F20B swaps also need the driver-side engine bracket from an H22/H23. Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ. BB1 → CB H22A engine and manual transmission (H-swap) Prelude VTEC (BB1) 1993-1996 → Accord (CB) 1990-1993 Yes — the H22A engine and manual transmission from a 1993–1996 Honda Prelude VTEC (BB1) fits a 1990–1993 Honda Accord (CB) with an H-series conversion mount kit and a weld-in or Accord-specific transmission bracket. Hasport sells its CBH kit for H22 and H23 swaps into the 90–93 Accord using 92–97 Prelude engines and transmissions, for both manual and automatic chassis. Innovative Mounts sells separate H-swap kits for the Accord EX (CB7/CB9) and DX/LX (CB7) and says they need the Accord F-series post mount 90008-PM3-000. The same Innovative kits also cover keeping the F-series engine with a 1994–2001 F-series manual gearbox. Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ. BB1 → EG1 H22A engine and manual transmission (H-swap) Prelude VTEC (BB1) 1993-1996 → Civic del Sol (EG1/EG2/EH6) 1994-1997 Yes — the H22A engine and manual transmission from a 1993–1996 Honda Prelude VTEC (BB1) fits a 1994–1997 Honda Civic del Sol with an EG/DC2-type H-series mount kit, H-swap axles and the Prelude H22 post mount. Hasport's EGH3 kit is sold for F or H-series engines in the 92–95 Civic, 94–97 del Sol and 94–01 Integra. Innovative Mounts lists its H-series conversion kit under the 93–97 del Sol and requires Honda post mount 11910-P13-000 plus an Accord or Prelude rear T-bracket. Insane Shafts H22/H23 swap axles are listed for the del Sol. Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ. BB1 → DA H22A engine and manual transmission (H-swap) Prelude VTEC (BB1) 1993-1996 → Integra (DA) 1990-1993 Yes — the H22A engine and manual transmission from a 1993–1996 Honda Prelude VTEC (BB1) fits a 1990–1993 Acura Integra (DA) with Innovative Mounts' DA H/F-series conversion kit, the Prelude H22 post mount 11910-P13-000 and H-swap axles. Innovative says the kit installs an H22 with little modification and includes a clutch actuator that works in the same plane as the clutch release fork. Insane Shafts H22/H23 swap axles are listed for DA and DC Integras. Innovative's EG/DC kit notes say 90–93 Integra axles work with an H-series gearbox when the right axle gets a Prelude/Accord inner CV joint. Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ. BB1 → EF H22A engine and manual transmission (H-swap) Prelude VTEC (BB1) 1993-1996 → Civic / CRX (EF) 1988-1991 Yes — the H22A engine and manual transmission from a 1993–1996 Honda Prelude VTEC (BB1) fits a 1988–1991 Honda Civic or CRX (EF) with a weld-in H-series mount kit, H-swap axles and a cable-to-hydraulic clutch solution. Innovative Mounts sells a conversion kit for the ED/EE/EF Civic and CRX that needs the passenger-side chassis mount welded in and a Prelude/Accord rear T-bracket. Hasport sells HP-EFHAX chromoly axles for the H-series swap into the 88–91 Civic/CRX, and Insane Shafts lists H22/H23 swap axles for EF Civics and CRXs. Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ. BB1 → CD5 H22A1 engine and manual transmission Prelude VTEC (BB1) 1993-1996 → Accord (CD5/CD7) 1994-1997 Yes — the H22A1 engine and manual transmission from a 1993-1996 Prelude VTEC (BB1) fits a 1994-1997 Accord (CD5/CD7) with H-series swap mounts, the Prelude rear bracket and the Prelude H-series timing-side post mount. Hasport's CDH1 kit is built around the Prelude transmission and rear bracket. Innovative lists conversion kits for the CD5, CD7 and CE1 with H22/F22A engines and manual transmissions and says no hood trimming is required. The H22A1 is rated at 190 hp in the US Prelude VTEC. Difficulty Moderate Modification required Fits VERIFIED ✓ MODS REQ. BB1 → EK H22A1 engine and manual transmission Prelude VTEC (BB1) 1993-1996 → Civic (EK) 1996-2000 Yes — the H22A1 engine and manual transmission from a 1993-1996 Prelude VTEC (BB1) fits a 1996-2000 Civic (EK) with an EK H-series mount kit, the 92-96 Prelude rear T-bracket and swap-length axles. Hasport lists its EKH3 kit for 93-97 H-series engines in the 96-00 Civic. Innovative says its EK H/F kit needs the 92-96 Prelude rear T-bracket and also works for F20B conversions using an H-series transmission. Expect more work than a B-series swap because the H22 is larger and heavier. Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ. BB1 → DC2 H22A1 engine and manual transmission Prelude VTEC (BB1) 1993-1996 → Integra (DC2) 1994-2001 Yes — the H22A1 engine and manual transmission from a 1993-1996 Prelude VTEC (BB1) fits a 1994-2001 Integra (DC2) with an EG/DC H-series mount kit, the Prelude H-series post mount and swap-length axles. Hasport lists its EGH3 kit for F- or H-series engines in the 92-95 Civic, 94-97 del Sol and 94-01 Integra. Innovative sells an equivalent kit for the EG and DC and notes A/C and power steering can be kept. Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ. FA5 → DC2 K20Z3 engine and 6-speed transmission Civic Si (FA5/FG2) 2006-2011 → Integra (DC2) 1994-2001 Yes — the K20Z3 engine and 6-speed transmission from a 2006-2011 Civic Si (FA5/FG2) fits a 1994-2001 Integra (DC2) with a K-series mount kit for the 02-11 Si gearbox, a K-swap harness and swap axles. Hasport lists the 2002-2011 Civic Si manual transmission as compatible with its DC2K2 kit. The K20Z3 is a 2.0 L i-VTEC rated at 197 hp, with VTEC on both cams and variable timing on the intake cam. Its electronic throttle is the main wiring difference from an RSX K20A2 swap. Difficulty Moderate Modification required Fits VERIFIED ✓ MODS REQ. FA5 → GD3 K20Z3 engine and 6-speed transmission Civic Si (FA5/FG2) 2006-2011 → Fit (GD3) 2007-2008 Yes — the K20Z3 engine and 6-speed transmission from a 2006-2011 Civic Si (FA5/FG2) fits a 2007-2008 Fit (GD3) with the Hasport GDK20 bracket kit, longer K-swap shifter cables and swap-specific wiring and axles. Hasport describes the GDK20 kit as brackets that use the stock Fit mounts with a K20 engine and the RSX or 02-11 Civic Si transmission. Hybrid Racing says its K20Z3 Fit cables work with the stock Fit shifter and the K20Z3 transmission. This is a full engine conversion and needs wiring, ECU, axle and cooling work beyond the mounts. Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ. FB6 → EK K24Z7 engine and 6-speed transmission Civic Si (FB6/FG4) 2012-2015 → Civic (EK) 1996-2000 Yes — the K24Z7 engine and 6-speed transmission from a 2012-2015 Civic Si (FB6/FG4) fits a 1996-2000 Civic (EK) with an EG or DC2 front subframe, steering rack and lower control arms, a K-series mount kit made for the 12-15 Si transmission, a matching harness and swap axles. Hasport lists its EKK5 version for the 08-13 Accord, 09-14 TSX and 12-15 Civic Si manual transmissions and says the EKK kit only works with the EG/DC2 subframe. The K24Z7 was rated at 201 hp (2012-2013) and 205 hp (2014-2015). Difficulty Moderate Modification required Fits VERIFIED ✓ MODS REQ. FB6 → GE8 K24Z7 engine and 6-speed transmission Civic Si (FB6/FG4) 2012-2015 → Fit (GE8) 2009-2013 Yes — the K24Z7 engine and 6-speed transmission from a 2012-2015 Civic Si (FB6/FG4) fits a 2009-2013 Fit (GE8) with the Hasport GEK3-24 mount kit, plus wiring, shifter cables, axles and cooling for the swap. Hasport says most GE Fit swaps use a K24Z engine, and Hybrid Racing lists GEK3 for the 12-15 Civic Si transmission (K24Z7). Hasport's dual-height mounts keep the head in the same place for K20 or K24. This is a full engine conversion; the mount kit is only one part of it. Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ. FB6 → GK5 K24Z7 engine and 6-speed transmission Civic Si (FB6/FG4) 2012-2015 → Fit (GK5) 2015-2020 Yes — the K24Z7 engine and 6-speed transmission from a 2012-2015 Civic Si (FB6/FG4) fits a 2015-2020 Fit (GK5) with the Hasport GKK3-24 mount kit plus swap wiring, shifter cables, axles and cooling. Hasport offers GKK2 and GKK3 versions, each in K20 and K24 variants, and uses a dual-height design so the head sits in the same place with either block. Hybrid Racing lists the same kit for 2015-2020 Fits. Neither listing offers a GK kit for the RSX/02-11 Civic Si gearbox. Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ. FC → EG L15B7 1.5 L turbo engine Civic Si (FC) 2017-2020 → Civic (EG) 1992-1995 Yes — the L15B7 1.5 L turbo engine from a 2017-2020 Civic Si (FC) fits a 1992-1995 Civic (EG) with the Hasport EGLT2 mount kit after engine bay modifications. Hasport lists the same kit for the Civic del Sol and the 1994-2001 Integra (DC2). Hybrid Racing describes the kit as covering L15B turbo variants broadly, not only the Si engine. Wiring, ECU and cooling for a modern turbocharged engine are the hardest parts of this swap and are not covered by the mount kit. Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ. FC → EK L15B7 1.5 L turbo engine Civic Si (FC) 2017-2020 → Civic (EK) 1996-2000 Yes — the L15B7 1.5 L turbo engine from a 2017-2020 Civic Si (FC) fits a 1996-2000 Civic (EK) with the Hasport EKLT2 mount kit and a DC2 or EG front subframe, after engine bay modifications. Hasport describes the swap as bolt-in once the engine bay is modified. Hybrid Racing lists the kit for the Civic Si L15B7 turbo engine in 62A, 70A and 88A bushing hardness. Wiring, ECU and cooling for the turbo engine are not covered by the mount kit. Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ. EF3 → EF ZC DOHC engine Civic Si (JDM) (EF3) 1988-1991 → Civic (EF) 1988-1991 Yes — the ZC DOHC engine from a 1988-1991 JDM Civic Si (EF3) fits a 1988-1991 Civic (EF) using the EF D-series mount positions and the JDM engine's harness and ECU adapted to the chassis. Wikipedia says the third-generation DOHC ZC appeared in the JDM EF3 Civic and EF7 CR-X from late 1987 to early 1991, so it was a factory engine in this chassis. Hasport lists its EFSTK kit as compatible with 88-91 JDM SOHC and DOHC ZC engines. Wikipedia describes the DOHC ZC as similar to the D16A1, D16A3, D16A8, D16A9 and D16Z5 rather than a separate engine family. Difficulty Moderate Modification required Fits VERIFIED ✓ MODS REQ.

RD1 → EG B20B/B20Z block with B-series VTEC head (B20/VTEC hybrid) CR-V (RD1) 1997-2001 → Civic (EG) 1992-1995 Yes — a B20 block from a 1997-2001 Honda CR-V (RD1) can be combined with a B16/B18 VTEC head and fitted to a 1992-1995 Honda Civic (EG) as a 'B20/VTEC' hybrid, using normal B-series swap mounts and a B-series gearbox. Civic-EG forum members describe it as not hard to assemble but expensive to make reliable, because the CR-V block was never designed for VTEC revs. They stress VTEC oil feed, dowel pins, rod bolt machine work and head studs as the key items. The result is more displacement than a B16/B18 swap but with more build risk. Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ. AP2 → AP1 F22C1 2.2L engine (AP2 into AP1) S2000 (AP2) 2004-2005 → S2000 (AP1) 2000-2003 Yes — the F22C1 from a 2004-2005 Honda S2000 (AP2) fits a 2000-2003 Honda S2000 (AP1) as a near drop-in replacement, with the main decision being ECU choice. S2Ki describes the 2004-2005 long block as the most plug-and-play option and says a stock F22C is pretty much plug and play in an AP1. Owners often keep the AP1 gearbox for its taller gearing and the lighter AP1 flywheel (about 14 lb versus 22 lb). Later 2006-2009 F22C1 engines can be used but need the AP1 intake, valve cover and sensors transferred. Difficulty Moderate Modification required Fits VERIFIED ✓ MODS REQ. EP3 → EP3 JDM K20A (Type R) engine Civic Type R (EP3) 2001-2005 → Civic Si (EP3) 2002-2005 Yes — the JDM K20A from a 2001-2005 Honda Civic Type R (EP3) fits a 2002-2005 Honda Civic Si (EP3) without mount changes, using a manual KPro ECU and a 02-04 style engine harness. The US EP3 Si came with the 160 hp K20A3, while Wikipedia lists the JDM Civic Type R K20A at about 158 kW (212 hp) at 8,000 rpm. Hondata confirms KPro supports both the US Civic Si ECU and the Japanese Civic Type R ECU. Wiring and ECU choice are the main jobs; the engine itself drops into the same chassis. Difficulty Moderate Modification required Fits VERIFIED ✓ MODS REQ. DC5 → DC5 JDM K20A (Type R) engine and 6-speed Integra Type R (DC5) 2001-2006 → RSX (DC5) 2002-2004 Yes — the JDM K20A from a 2001-2006 Honda Integra Type R (DC5) fits a 2002-2004 Acura RSX (DC5) with no mount changes, using a K20A2-style harness and a KPro or compatible manual ECU. Hondata's KPro covers both the US RSX ECUs and the JDM Type R PRC ECU, which is why this is one of the most common K-series upgrades. Wikipedia lists the JDM Integra Type R K20A at about 162 kW (217 hp) at 8,000 rpm with an 8,400 rpm redline, versus 200 hp for the 2002-2004 RSX Type-S K20A2. Base RSX owners fitting the 6-speed should use a 6-speed (K20A2) harness and ECU if they want the reverse lockout to work. Difficulty Moderate Modification required Fits VERIFIED ✓ MODS REQ. FG2 → FG1 K20Z3 engine and 6-speed (K-swap) Civic Si (FG2/FA5) 2006-2011 → Civic (FG1/FA1 (R18)) 2006-2011 Yes — the K20Z3 and 6-speed from a 2006-2011 Honda Civic Si (FG2/FA5) fits a 2006-2011 Honda Civic with the R18 engine (FG1/FA1) using Hasport's FGK1 mount kit. Hasport states the kit is for R18 cars only and can also be used with K20A, K20Z and K24A engines. Using the 06-11 Civic Si transmission with Si shift cables lets the stock manual shifter work. Because the donor and recipient share a body, many interior and chassis parts are already Si-compatible. Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ. CR-V → RD1 K24A1 engine with AWD manual transmission (K-swap) CR-V (2nd gen) 2002-2006 → CR-V (RD1) 1997-2001 Yes — the K24A1 and AWD manual transmission from a 2002-2006 Honda CR-V fits a 1997-2001 Honda CR-V (RD1) with Hasport's RD1KMAWD mount kit, FCS Race shock forks and RD1 K-swap axles, keeping all-wheel drive. Hasport describes the swap as largely bolt-in apart from some subframe modification. An automatic AWD version of the kit (RD1KAAWD) also exists. It replaces the RD1's B20B/B20Z with a K20 or K24. Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ. FB6 → ZF1 K24Z7 engine and 6-speed (K-swap) Civic Si (FB6/FG4) 2012-2015 → CR-Z (ZF1/ZF2) 2011-2016 Yes — the K24Z7 and 6-speed from a 2012-2015 Honda Civic Si (FB6/FG4) fits a 2011-2016 Honda CR-Z (ZF1/ZF2) with the Hasport ZFK3-24 mount kit. Hasport makes ZFK kits for K20 and K24 engines with RSX/Civic Si, Accord/TSX and 12-15 Civic Si transmissions, and Hybrid Racing sells the kit for 2011-2016 CR-Z. The swap replaces the hybrid LEA engine and IMA assembly entirely. Mounts are the only bolt-in part; wiring and engine management are the main engineering work. Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ.

BB1 → EG H22A engine and gearbox Prelude (BB1) 1992-1996 → Civic (EG) 1992-1995 With a Hasport EG H-series mount kit and Hasport driveshafts the H22A is effectively a bolt-in swap; only the wiring needs custom adaptation. The passenger-side axle reuses the H22A intermediate shaft with the Hasport shaft fitting straight into it; the driver side is a complete Hasport assembly. The Civic clutch slave cylinder is used instead of the Prelude one for clearance and bolts on with one extra hole drilled in the bracket; the Civic reverse light switch fits the H22A gearbox directly. The Civic reverse-flow fuel line from rail to filter needs fabrication, and an uprated in-tank fuel pump (Walbro GSS341 here) is recommended. A standard EG intake pipe and pod filter fits the H22A. Documented result: 14.2 s quarter mile at 101 mph with only intake and 2.5-inch exhaust; total swap cost $5,545 on-road (2004). Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ. DC2 → EG JDM B18C (Type R) engine with S80 LSD gearbox Integra Type R (DC2) 1995-1998 → Civic (EG) 1992-1995 The B18C fits the EG engine bay using all factory Integra Type R mounts with no clearance problems. ITR driveshafts (1996-on), the ITR accelerator cable, power steering hose, shift linkage and fuel/heater/vacuum connections all line up with the EG without fabrication. Sourcing a complete front cut is the recommended approach because it supplies the engine, S80 gearbox, ECU, engine loom, mounts, driveshafts and cables in one purchase. Aftermarket conversion mounts (Hasport, AVID) are an alternative to factory ITR mounts, but each brand positions the engine slightly differently, affecting bonnet and chassis-rail clearance. A carbureted EG first needs a full EFI conversion (fuel lines, tank, pump). Both the JDM Type R and JDM SiR engines are stamped "B18C"; identify the Type R by its S80 LSD gearbox, intake manifold and rocker cover. Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ.

EP3 → EG K20 Engine Swap Civic EP3 (7th gen) 2001-2005 → Civic EG (5th gen) 1992-1995 One of the most popular engine swaps for EG Civic. K20A2 from EP3 Type R provides 200hp and VTEC. Difficulty Expert Modification required Fits VERIFIED ✓ MODS REQ.

K20A → EG K20A engine and transmission K-series (K20A) → Civic (EG) / Integra (DC) (EG / DC chassis) The K20A does not bolt to the factory B/D mounting points and requires a dedicated conversion mount kit. The kit provides a rear mount bracket that fastens to the subframe, a timing-chain-side mounting arrangement (small and large mounts) that reuses the passenger-side tow-hook location, and a driver-side transmission bracket. Supplied 1/2 inch spacers set the transmission bracket standoff on the rear crossmember side and take up the differing bolt-point heights on the driver-side bracket. The factory engine-harness plugs are pushed through the firewall and retained under the dash for later wiring rather than being cut. This entry covers Part 1 (mechanical fitment and mounting) only; wiring, cooling, and axle integration are separate phases. Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ.

K24A → DC5 K24 short block (K24/K20A2 hybrid) CR-V (K24A short block) → RSX Type S (DC5) 2002-2006 The K24 bottom end (crank, rods, pistons) is retained, while the head, cam caps, VTC actuator, timing chain, tensioner, slide rails, oil pump, oil pan, oil cooler, windage tray, knock sensor, and their fasteners transfer from the K20A2. The K20A2 water pump, oil cooler, and intake also carry over. Because the hybrid combination changes how the timing indexes, the marks will not line up on their own; set the crank to TDC and align them by hand. On the dyno the build has shown about 185 whp with roughly 30 lb-ft more torque across the band, forming a good base for boost (300+ whp capable). A CR-V donor is the cheap, plentiful choice; a TSX block adds higher compression, stronger rods, and factory oil squirters. Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ.

K20A2 → DC2 K24A1 block with K20A2 head (hybrid K-series engine swap) CR-V (K24A1) with K20A2 head 2002-2006 → Integra Type R (DC2) (DC2) 1995-2001 K24/K20 hybrid engines physically install in the DC2 as a standard K-swap, but the wiring is the hard part when a European donor harness is combined with a USDM ECU. Getting the engine to crank, start and datalog does not confirm the sensor wiring is correct: coolant temp (ECT), cam position (CMP) and wideband O2 channels can all stay blank. Plan on a full re-pin of the engine harness to the USDM PRB ECU pinout, correct wideband O2 wiring per the Hondata CTR reference, and verification that the shared sensor power group at C101 is actually hot. Note that missing ECT/CMP/O2 readings can also be caused by the ECU itself (counterfeit or a failed internal 5 V reference), so the ECU should be proven in a known-good car before the harness is condemned. Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ.

FB6 → EG K24Z7 engine Civic Si (9th gen (FB6/FG4)) 2012-2015 → Civic (EG) 1992-1995 Completed, running swap documented by the builder, with a full video how-to series (parts, wiring, ECU) on the BallsOutPerformance YouTube channel; at the time there was essentially no other public information on swapping the K24Z7. Key fitment facts from the thread: a K20 transmission bolts up to the K24Z7 block (confirmed by the builder); the builder ran the A2 halfshaft with regular Driveshaft Shop swap axles. For the closely related EK-chassis version discussed in the thread: Hasport EKK5 mounts were used and the rear engine subframe had to be changed to fit; non-engine electrics (wipers, lights, etc.) keep working as stock, and a good EK power pick-up point for engine wiring is the driver's strut tower plug (large wire to starter; BLK/YEL fused at 15 A for ignition coils; YEL/BLK for ECU feed; second BLK/YEL for O2 sensors; BLK ground; YEL/GRN temp gauge; YEL/RED oil pressure light; WHT/BLU alternator L terminal / battery warning light). Difficulty Difficult Modification required Fits VERIFIED ✓ MODS REQ.