Build a Land Cruiser pickup (short bed, minimal frame) with a front diesel engine (driving front crawler wheels + rear water propeller) and a rear Honda CR-V VTEC engine (driving rear two wheels individually). Each wheel has an independent electric hub motor (“El trick rotors”). An inflatable air bag under the frame allows water travel.
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1. Chassis & Body Prep
1.1. Source a Toyota Land Cruiser pickup (70-series or older 40/45 series with short bed). Strip everything except cab, minimal frame rails, and suspension mounting points.
1.2. Cut away excess frame – keep only two main longitudinal rails (no crossmembers except at suspension mounts). Weld reinforcing box sections if needed.
1.3. Remove original engine, transmission, fuel tank, driveshafts, axles – you will not use mechanical axles.
1.4. Fab new body mounts to keep the bed floor but leave space underneath for the inflatable raft.
1.5. Sandblast and rust-proof the remaining frame.
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2. Front Diesel Engine & Propeller Drive
2.1. Mount a compact diesel engine (e.g., 1.9L TDI, 3B, or 4BT) between front frame rails. Use custom engine mounts.
2.2. Connect diesel to a hydraulic pump OR a PTO splitter – you need two outputs:
- One to a generator (for front hub motors – see step 5)
- One to a long driveshaft running to the rear for the propeller.
2.3. Install a dog clutch on the propeller shaft so you can disengage on land.
2.4. Mount a marine propeller (small, e.g., 10″ diameter) on a swing-down bracket at the very back of the frame, below the bed. Align the driveshaft to it via a right-angle gearbox (or use a jet ski pump for shallower water).
2.5. Add a rudder linked to the steering column (cable or hydraulic) for water steering.
2.6. Install a separate small fuel tank for diesel (keep away from electrical components).
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3. Rear Honda VTEC Engine & Individual Rear Wheel Drive
3.1. Mount a Honda CR-V K24 VTEC engine in the bed, centrally between the wheel arches. Use a custom subframe bolted through the bed floor to the frame rails.
3.2. Do NOT connect the VTEC to a mechanical differential – instead, couple it to a high-output alternator/generator (e.g., 48V 10kW unit) or two separate generators (one for each rear wheel).
3.3. Mount two independent electric hub motors inside the rear wheels (see step 5). The VTEC’s generator(s) feed a battery pack that powers these hub motors.
3.4. Add a separate radiator for the VTEC engine, mounted behind the cab or under the bed with electric fans.
3.5. Exhaust – route dual side-exit pipes ahead of the rear wheels to avoid the inflatable raft.
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4. “El Trick Rotor Hubs” – Individual Electric Hub Motors for All 4 Wheels
4.1. Procure four identical in‑wheel hub motors (e.g., QS Motor 273 10kW, or salvaged from electric UTVs). Each must have its own controller and rotor/hub assembly.
4.2. Fabricate custom spindles to mount each hub motor to the Land Cruiser’s original suspension (front: IFS or solid axle; rear: leaf springs). Maintain original bolt pattern if you want to reuse Toyota wheels.
4.3. Run high‑current cables (welding cable gauge) from each motor’s controller to a central power distribution box.
4.4. Install position/speed sensors (hall effect or encoder) on each hub motor – required for the brain.
4.5. Add mechanical disc brakes on the stationary part of each hub (or use the motor’s regenerative braking as primary, with a small mechanical backup).
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5. The “Brain” – Control System
5.1. Choose a rugged microcontroller – Arduino Mega with CAN bus shield, or Raspberry Pi 4 with a real‑time co-processor, or an industrial PLC (e.g., Automation Direct CLICK).
5.2. Wire inputs:
- Throttle pedal (two sensors – one for diesel, one for VTEC/throttle‑by‑wire)
- Mode selector switch (Crawl / Rear Assist / Water)
- Wheel speed sensors (from each hub motor controller)
- Water depth sensor (ultrasonic or float switch)
- Air bag pressure transducer
- Propeller shaft speed (hall sensor)
5.3. Wire outputs:
- Diesel engine throttle actuator (if electronically controlled) or governor solenoid.
- VTEC engine throttle (drive‑by‑wire or servo on carb/manifold).
- Hub motor controller enable signals (0‑5V or CAN commands).
- Propeller dog clutch actuator (electric solenoid).
- Air bag inflation valve and pump relay.
- Rudder servo (optional for auto‑course holding).
5.4. Program control logic (pseudocode – adjust to your hardware):
```
MODE = read_selector()
if MODE == "CRAWL":
diesel_on = true
vtec_on = false
propeller_clutch = disengaged
front_hubs = follow_throttle() # diesel generator provides power
rear_hubs = 0
if throttle > 10%: front_hubs_power = map(throttle, 0,100, 0, max_torque)
if MODE == "REAR ASSIST":
diesel_on = true
vtec_on = true
propeller_clutch = disengaged
front_hubs = follow_throttle() * 0.6 # 60% power
rear_hubs = follow_throttle() * 0.4 # 40% individual control
# Rear left/right can differ for turning (torque vectoring)
if MODE == "WATER":
if water_depth > 0.3m and air_bag_pressure < 2psi:
inflate_air_bag()
diesel_on = true
vtec_on = false
propeller_clutch = engaged
front_hubs = 0 # freewheel
rear_hubs = 0
propeller_speed = map(throttle, 0,100, idle_rpm, diesel_max_rpm)
# steering = rudder instead of wheel torque
```
5.5. Build a waterproof control box mounted in the cab. Include emergency stops for both engines and a manual override for the air bag.
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6. Inflatable Raft / Air Bag System
6.1. Measure the area between the two frame rails – from just behind the front bumper to just ahead of the rear propeller. This is your “raft” footprint.
6.2. Order a custom drop‑stitch PVC air bladder (like an inflatable boat floor) with dimensions: length = wheelbase, width = frame rail outer‑to‑outer. Thickness when inflated ~8–12 inches.
6.3. Attach the bladder to the frame using heavy‑duty Velcro straps or bolt‑on fabric loops – it must deflate flat against the frame bottom.
6.4. Install a 12V high‑volume air pump (e.g., 2 CFM, 150 psi) with a pressure switch that stops at ~3 psi (just enough to float the truck, not burst).
6.5. Add a manual dump valve for quick deflation when exiting water.
6.6. Protect the bladder from road debris with a thin aluminum or UHMW skid plate that hinges open when inflated (optional but recommended).
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7. Fuel, Cooling & Electrical Systems
7.1. Fuel – Two separate tanks: diesel for front engine, gasoline for VTEC. Mount them low and centered to avoid tipping. Use anti‑slosh foam.
7.2. Cooling – Front diesel: radiator behind grille with electric fan. VTEC: second radiator under the bed with ducted airflow. On water mode, run both fans continuously.
7.3. Battery – A large LiFePO4 pack (48V, 10–20 kWh) to buffer generator output and power hub motors. Place it under the cab floor (sealed, ventilated).
7.4. Alternators – The diesel and VTEC each need high‑output alternators (or generators) to charge the battery pack. Rectify AC to DC if using generators.
7.5. Wiring – Use marine‑grade, tinned wire everywhere. All connectors waterproofed with dielectric grease and heat shrink.
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8. Final Assembly & Testing Sequence
8.1. Dry assembly – Mount everything except hub motors. Verify frame clearance for the air bag.
8.2. Weld / bolt all brackets – engine mounts, radiator supports, propeller bracket, air bag straps.
8.3. Install hub motors – torque to spec, wire each controller to the brain and to the battery.
8.4. Connect fuel lines, cooling hoses, exhaust – no leaks.
8.5. Upload brain software – bench test all inputs/outputs using signal simulator.
8.6. First start (dry land, wheels off ground) – Test diesel start, VTEC start, hub motor free spin, propeller engagement (disconnected from water).
8.7. Crawl test – On grass, slowly drive using only front hub motors. Verify air bag stays deflated.
8.8. Rear assist test – Engage VTEC generators, feel rear wheels help climbing a small slope.
8.9. Water test – In a pond or calm river: deflate air bag to minimum, drive slowly into water. Activate “Water” mode. Air bag should inflate within 30 seconds. The truck should float. Engage propeller – it should push you forward at 3‑5 mph. Use rudder to turn.
8.10. Recovery – Drive back onto land, dump air bag, switch to Crawl mode, drive out.
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9. Safety & Legal Considerations
9.1. On‑road legality – This vehicle will likely never be street legal (twin engines, no certified axles, inflatable raft). Use only off‑road or as a watercraft.
9.2. Buoyancy calculation – Before water test, calculate displacement. The air bag must displace at least 1.5× the truck’s weight. A 10″ thick bag under a 12′ × 3′ area displaces ~300 gallons = ~2,500 lbs buoyancy – enough for a 4,000‑lb truck if you add supplemental flotation in doors.
9.3. Emergency cutoffs – Install two large red buttons: one kills all electric hub motors, the other kills both engines and opens the air bag dump valve.
9.4. Fire suppression – Have a marine‑rated extinguisher in the cab and one near the VTEC engine.
9.5. Waterproofing – Seal all electrical enclosures to IP67. Use dielectric grease on every connector.
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10. Optional Upgrades
· GPS‑based mode switching – automatically inflate bag when water is detected.
· Solar panel on bed cover – trickle charge the battery while parked.
· Hydrofoils – fold down from the frame to lift the truck partially out of water for speed.
· Remote control – for operating the truck from a chase boat during initial water tests.
Fabrication project – expect 100+ hours and a budget starting at $15,000 (mostly for hub motors, controllers, and custom air bag).