Toyota 15B-FTE Specifications
| Engine Model: Toyota 15B-FTE |
| Engine Type: 4-cycle inline 4-cylinder direct-injection liquid-cooled diesel |
| Total Displacement: 250.5 cu.in (4.1 L) |
| Rated Engine Power: 151 Hp (112 kW) at 3200 rpm |
| Aspiration Type: Turbocharged, intercooled |
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The Toyota 15B-FTE is a 4.1-liter, inline
four-cylinder, direct-injection, turbocharged, and intercooled diesel
engine designed for high durability and efficient performance. It is
part of Toyota’s long-standing “B” series of diesel engines that are
recognized for their mechanical simplicity, reliability, and high torque
output suitable for heavy-duty and commercial applications.
Produced mainly by Toyota’s Hino division, the
15B-FTE was developed as the most advanced version of the B family,
incorporating electronic fuel control for enhanced combustion precision
and reduced emissions. The engine saw service primarily in Toyota Land
Cruiser 70 Series utility models and in light commercial vehicles across
multiple markets, where durability and long service life were essential.
The 15B-FTE shares its basic architecture with its predecessor, the
15B-FT, but features an electronically controlled fuel injection system
(EFI) managed by an engine control unit (ECU). The electronic control
allows more accurate injection timing and fuel metering, improving both
performance and emissions. Its turbocharged and intercooled
configuration produces higher power output than naturally aspirated
B-series engines, while retaining the low-speed torque and mechanical
robustness for which this engine family is famous. Built around a
cast-iron block and head, it provides exceptional thermal and structural
rigidity for sustained heavy use.
Engine type: Four-stroke, inline 4-cylinder OHV direct injection
turbocharged diesel engine
Displacement: 4,104 cc (4.1 L / 250.5 cu in)
Bore x Stroke: 108.0 mm x 112.0 mm (4.25 in x 4.41 in)
Compression ratio: 17.6:1
Maximum power output: 153 PS (151 hp / 112 kW) at 3,200 rpm
Maximum torque: 380 Nm (280 lb-ft) at 1,800 rpm
Firing order: 1–3–4–2
Number of valves: 8 (2 valves per cylinder)
Valve mechanism: Overhead valve (OHV) pushrod type with rocker arms and
adjustable tappets
Turbocharger: Toyota CT26-based turbocharger with air-to-air intercooler
Fuel system: Electronically controlled direct-injection diesel (Denso
EDC system)
Fuel type: Diesel fuel, ASTM D975 No.2 or JIS No.2 grade
Aspiration: Turbocharged and intercooled
Governor type: Electronic control type with load-sensing feedback
Timing gear drive: Helical gear-driven camshaft and injection pump
Cooling method: Pressurized water circulation via belt-driven
centrifugal pump and thermostat
Lubrication: Full-pressure feed with trochoid oil pump, full-flow
filter, and oil cooler
Emission level: Euro I–II compliant (varies by market)
Idle speed: 750 ± 50 rpm
Operating range: 750–3,200 rpm continuous
The fuel system of the 15B-FTE is an electronically controlled
direct-injection type. A Denso EDC distributor-type fuel injection pump
delivers high-pressure diesel directly to each injector. The ECU
calculates injection quantity and timing using input data from sensors
that monitor crankshaft position, intake manifold pressure, coolant
temperature, and accelerator pedal position. The injectors are
multi-hole, pintle-type nozzles capable of fine atomization under
pressures exceeding 21 MPa (3,000 psi).
Fuel is drawn from the tank by a low-pressure supply pump through a
primary fuel filter and water separator. The fuel is then delivered to
the injection pump inlet. A return circuit recirculates excess fuel to
the tank, providing continuous cooling and lubrication to the pump. The
ECU-controlled system improves throttle response, reduces smoke under
acceleration, and enhances cold-start performance compared with
mechanically governed predecessors such as the 14B-T and 15B-FT.
The lubrication system is of the full-pressure type, using a gear-driven
trochoid oil pump. Lubrication oil is drawn through a coarse pickup
strainer in the sump and forced through a full-flow, spin-on oil filter.
The main oil gallery supplies oil to the crankshaft, connecting rod
bearings, camshaft, rocker gear, and timing gears. A bypass oil cooler
is incorporated into the system, maintaining optimal viscosity under
heavy loads. Turbocharger bearings are supplied by a dedicated
pressurized feed line, with gravity return to the sump. The lubrication
system ensures reliable operation even at high oil temperatures typical
of heavy-duty use.
Oil capacity: 8.5 liters (9.0 US qt)
Recommended oil: SAE 15W-40 API CF, CF-4, or higher
Oil pressure: 350–450 kPa (51–65 psi) at 2,500 rpm
The 15B-FTE uses a closed-circuit, pressurized cooling system that
employs a belt-driven centrifugal water pump to circulate coolant
through the cylinder block and head. A wax-pellet thermostat regulates
flow to the radiator to maintain consistent operating temperature. The
radiator is a cross-flow aluminum or copper core type equipped with a
pressure cap rated at 0.9 bar (13 psi). A viscous-drive or electric
cooling fan maintains airflow across the radiator core. The turbocharger
also receives coolant flow to reduce bearing temperatures and prevent
coking after shutdown.
Coolant capacity: 10.5 liters (11.1 US qt)
Thermostat opening temperature: 82°C (180°F)
Normal operating temperature: 85–95°C (185–203°F)
| Intake and Exhaust Systems |
The air intake system consists of a dry-element air cleaner with
restriction indicator, an intake duct, turbocharger compressor,
intercooler, and intake manifold. Boost pressure is approximately 0.8
bar (11.6 psi). The intercooler reduces intake air temperature by
50–60°C, improving air density and combustion efficiency. The exhaust
system includes a cast-iron manifold, turbocharger turbine housing,
downpipe, and muffler, designed to maintain exhaust back pressure below
10 kPa (1.5 psi) at rated power.
| Electrical and Starting Systems |
Electrical supply is 12V or 24V negative ground, depending on the
application. The alternator is rated at 80 amps, with optional 24V 50A
versions for industrial models. The starter motor output ranges from 2.5
to 4.0 kW. The ECU operates on a regulated 5V logic supply derived from
the main circuit. Cold starting is assisted by a glow plug system
controlled by a timer relay and temperature sensor. Typical glow plug
resistance is 0.6–1.0 ohm, and glow duration varies from 3 to 10 seconds
based on coolant temperature.
Overall length: 860 mm (33.9 in)
Overall width: 720 mm (28.3 in)
Overall height: 910 mm (35.8 in)
Dry weight: approximately 330 kg (728 lb)
Flywheel housing: SAE No. 3 standard
Crankshaft center height: 260 mm (10.2 in)
Balance type: Internal, with counterweighted crankshaft
Oil change interval: 10,000 km (6,200 miles) or 250 operating hours
(whichever occurs first)
Fuel filter element: Replace every 20,000 km (12,400 miles)
Air cleaner element: Inspect every 5,000 km (3,100 miles), replace if
necessary
Valve clearance (cold): Intake 0.25 mm (0.010 in), Exhaust 0.35 mm
(0.014 in)
Cooling system flush: Every 40,000 km (25,000 miles) or 2 years
Fan belt tension: Deflection 8–10 mm (0.31–0.39 in) under 98 N (22 lbf)
Battery charging voltage: 13.8–14.5 V at 2,000 rpm
Injection timing: ECU controlled (base setting 9° BTDC)
Idle speed: 750 ± 50 rpm
Cylinder head bolts: 118 Nm (87 lb-ft) + 90° turn in sequence
Main bearing cap bolts: 132 Nm (97 lb-ft)
Connecting rod bolts: 54 Nm (40 lb-ft) + 90° turn
Flywheel bolts: 120 Nm (89 lb-ft) + 45°
Injector hold-down bolts: 27 Nm (20 lb-ft)
Glow plug torque: 11 Nm (8 lb-ft)
Rocker shaft bolts: 35 Nm (26 lb-ft)
Oil pan bolts: 9 Nm (7 lb-ft)
Timing gear cover bolts: 12 Nm (9 lb-ft)
Crankshaft pulley bolt: 370 Nm (273 lb-ft)
Turbocharger mounting nuts: 45 Nm (33 lb-ft)
The Toyota 15B-FTE engine was fitted
primarily to the following vehicles:
– Toyota Land Cruiser 70 Series (models HZJ79, HZJ78, HZJ75, and HZJ73,
depending on market)
– Toyota Dyna 400 and ToyoAce trucks (selected export versions)
– Hino light-duty trucks (industrial variants)
– Agricultural and construction machinery requiring high torque at low
engine speeds
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