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Converting a Honda Prelude from FF (front-engine, front-wheel drive) to FR (front-engine, rear-wheel drive) — that’s a very ambitious drivetrain conversion.
Let’s break it down step-by-step so you understand what’s required, what’s possible, and what’s practical.
⚙️ 1. The Starting Point: Prelude FF Layout
All Honda Preludes (from 1st to 5th gen) are front-engine, front-wheel drive (FF).
They have:
- Transverse engine layout.
- Front subframe carrying the engine + transaxle.
- No rear driveshaft tunnel or differential mounts.
To convert it to FR, you basically need to redesign half the car’s structure.
🔩 2. What’s Involved in FF → FR Conversion
This is not a simple drivetrain swap — it’s a full chassis + drivetrain re-engineering.
✅ Major Components to Modify or Replace
| System | What Must Be Done |
|---|---|
| Engine Orientation | Rotate 90° to mount longitudinally (FR layout). Custom engine mounts + transmission tunnel cutting. |
| Transmission | Replace FWD transaxle with a RWD gearbox (e.g., S2000 6-speed or Nissan SR20/KA24 box). |
| Driveshaft | Custom driveshaft from gearbox output to rear diff. |
| Rear Subframe | Fabricate or swap in rear subframe with independent suspension & diff mounts. Often borrowed from S2000, Miata, or 240SX. |
| Differential & Axles | Install RWD differential (often from donor chassis, e.g. S2000, Miata, BMW E36). |
| Chassis Reinforcement | Weld in transmission tunnel, driveshaft clearance, and structural bracing. Roll cage or subframe connectors recommended. |
| Steering System | Front suspension geometry must be redesigned if engine orientation changes. |
| Electronics | ECU + wiring harness must be heavily modified or standalone ECU used. |
🚗 3. Common Donor Parts & Hybrid Builds
Some successful conversions or near-equivalents:
- Engine + transmission: Honda F20C (S2000), K20 + RWD gearbox (KMiata conversion), or SR20DET (Nissan).
- Rear end:
- Option A: S2000 rear subframe + diff + suspension — best fit for FR Honda builds.
- Option B: Miata NA/NB rear cradle — more compact but still requires cutting.
- Front end: Custom tubular subframe for longitudinal engine.
🔥 4. Engineering Challenges
| Area | Difficulty | Notes |
|---|---|---|
| Structural Reinforcement | 🔴 Extreme | Cutting floorpan weakens monocoque; requires welding skills. |
| Driveline Alignment | 🔴 Extreme | Ensuring straight-line between engine, gearbox, diff, and axles. |
| Cooling & Exhaust | 🟠Moderate | Radiator and exhaust rerouting. |
| Electrical Integration | 🟠Moderate | ECU remap, sensors, immobilizer bypass, etc. |
| Suspension Geometry | 🔴 Critical | Front/rear camber and roll center must be recalculated. |
💰 5. Cost and Effort Estimate
| Component | Typical Range |
|---|---|
| Donor drivetrain (e.g. F20C + gearbox + diff) | $5,000–$8,000 |
| Fabrication + labor | $4,000–$10,000 |
| Suspension & brakes | $2,000–$4,000 |
| ECU + wiring | $1,000–$2,000 |
| Total | $12,000–$25,000+ depending on DIY vs shop work |
💰 5. Cost and Effort Estimate
| Component | Typical Range |
|---|---|
| Donor drivetrain (e.g. F20C + gearbox + diff) | $5,000–$8,000 |
| Fabrication + labor | $4,000–$10,000 |
| Suspension & brakes | $2,000–$4,000 |
| ECU + wiring | $1,000–$2,000 |
| Total | $12,000–$25,000+ depending on DIY vs shop work |
🧰 6. Alternatives (If Full FR Conversion Is Too Much)
If your goal is handling balance or drift feel, consider:
- Mid-engine swap (MR) using a K20 or F20C (like some custom Civics/Preludes).
- “Fake FR” feel: Lock out front diff, use rear electric assist motor (hybrid RWD assist concept).
- Or simply tune the FF chassis — weight balance, LSD, coilovers, rear toe control arms, etc.
⚡ 7. Example Inspiration
You can check out:
- YouTube: “FR Prelude project” or “S2000 swapped Prelude” — some fabricators documented FR conversions.
- KMiata / KPower Industries for longitudinal K-engine mounting kits (for Miata base, adaptable to Prelude if you’re creative).
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