Nissan VQ25DD Specifications
| Engine Model: Nissan VQ25DD |
| Engine Type: 4-cycle 6-cylinder V-block DOHC 24-valve eVTC liquid-cooled gasoline |
| Total Displacement: 152.3 cu.in (2.49 L) |
| Rated Engine Power: 207-212 Hp (154-158 kW) at 6400 rpm |
| Fuel System Type: Direct injection gasoline |
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The Nissan VQ25DD is a 2.5-liter V6 engine from the VQ
family, representing the direct-injection variant of the VQ25 series. Produced
between 1999 and 2007 for the Japanese Domestic Market, the VQ25DD incorporates
Nissan’s NEO Di direct injection technology, which injects fuel directly into
the combustion chamber at high pressure. This configuration enables a higher
compression ratio, improved fuel atomization, and enhanced thermal efficiency
compared to the port-injected VQ25DE.
The engine features a 60-degree aluminum alloy block and cylinder heads, dual
overhead camshafts with electronic variable valve timing (eVTC) on the intake
camshafts, and a maintenance-free timing chain system. The VQ25DD powered the
Skyline V35, Cedric, Gloria, Stagea, and Fuga across multiple generations,
delivering a balance of power output and fuel economy suited to premium sedan
applications.
Engine Type: 60° V6, 4-cycle, water-cooled, naturally aspirated gasoline.
Displacement: 2,495 cc (152.3 cu.in).
Bore: 85.0 mm (3.35 in).
Stroke: 73.3 mm (2.89 in).
Compression Ratio: 11.0:1 to 11.3:1 depending on model year.
Firing Order: 1-2-3-4-5-6.
Maximum Power Output: 207-212 hp (154-158 kW) @ 6,400 rpm.
Maximum Torque Output: 265-270 Nm (195-199 lb-ft) @ 4,400 rpm.
Redline: 7,000 rpm.
Valvetrain Configuration: Dual Overhead Camshaft (DOHC) per cylinder bank,
operating 24 valves (4 valves per cylinder). The intake camshafts are equipped
with electronic Variable Timing Control (eVTC), a hydraulically actuated system
that continuously adjusts intake cam timing across the engine speed range.
Camshafts are driven by a silent timing chain.
The cylinder block is manufactured from aluminum alloy
with a 60-degree V-angle configuration. Bore diameter measures 85.0 mm (3.35
in). The block features a closed-deck design with cast-in iron cylinder liners
to provide wear-resistant bore surfaces. The crankshaft is forged steel with
eight counterweights, supported by four main bearings.
The block incorporates an integrated oil gallery system feeding the main
bearings, connecting rods, and variable valve timing components. A structural
aluminum lower crankcase (bedplate) replaces individual main bearing caps,
increasing overall block stiffness while maintaining low mass. The lightweight
aluminum construction contributes to reduced overall engine weight.
Each cylinder head is manufactured from aluminum alloy
with pent-roof combustion chambers and cross-flow port architecture, optimized
for direct injection.
Valves: 24 total; 12 intake, 12 exhaust.
Intake Valve Diameter: 32.0 mm (1.26 in).
Exhaust Valve Diameter: 28.0 mm (1.10 in).
Valve Stem Diameter: 5.5 mm (0.22 in) for both intake and exhaust, reduced from
earlier VQ variants to lower reciprocating mass and friction. Valve Seat
Inserts: Powder metal sintered alloy with multi-angle seat geometry designed for
direct injection combustion characteristics. Valve Guides: Press-fit sintered
iron guides.
Hydraulic Lash Adjusters: Direct-acting units mounted in the cylinder head
casting, operating on bucket-type cam followers. These adjusters automatically
maintain zero valve clearance throughout engine life.
Camshafts: Hollow cast iron camshafts with assembled lobes to reduce rotational
inertia. Each bank contains separate intake and exhaust camshafts. The intake
camshaft incorporates the eVTC actuator, which hydraulically advances and
retards cam timing continuously based on engine operating conditions.
eVTC System: Oil pressure controlled by a solenoid valve adjusts the intake
camshaft phase angle across a range of 40 degrees (20 degrees advance, 20
degrees retard). The system operates across the entire engine speed and load
range, optimizing volumetric efficiency and reducing pumping losses. Valve
Springs: Low-friction beehive-type springs with reduced seat pressure to
minimize parasitic losses.
The fuel system employs Nissan’s NEO Di direct
injection technology with high-pressure fuel delivery. Injection Type: Direct
injection into the combustion chamber with injectors mounted centrally in the
cylinder head between the intake and exhaust valves. Injector Configuration:
High-pressure solenoid injectors with multi-hole nozzles designed for stratified
charge operation at low loads and homogeneous operation at higher loads.
Fuel Pressure: Low-pressure circuit supplies fuel from the in-tank pump at
3.0-4.0 bar (44-58 psi). A high-pressure mechanical pump driven by the intake
camshaft of the right bank elevates pressure to a maximum of 120-140 bar
(1,740-2,030 psi) depending on engine speed and load. High-Pressure Pump:
Single-piston plunger pump with a fuel metering valve controlling rail pressure
based on engine demand.
Engine Management System: Nissan ECU with advanced combustion control algorithms
managing stratified charge operation, injection timing, and eVTC calibration.
Intake Manifold: Composite plastic manifold with integrated intake air
temperature sensor and electronically controlled throttle body. The manifold
incorporates swirl control valves that alter intake port velocity to promote
mixture formation under stratified charge operation.
The lubrication system is a full-flow, pressurized
design utilizing a variable displacement oil pump to reduce parasitic losses
across the operating range. Oil Pump Type: Variable displacement vane-type pump
mounted to the front of the crankshaft. Pump displacement is regulated by the
engine control unit via a solenoid valve that adjusts the pump’s stroke based on
engine speed, load, and oil temperature.
Oil Capacity: 4.5-4.9 liters (4.8-5.2 qt) including oil filter replacement.
Recommended Oil Viscosity: 5W-30 or 0W-30. Low-viscosity oils are specified to
minimize friction losses. Oil Quality Requirement: API SL, SM, or later
classifications. ILSAC GF-3 or GF-4. Oil Pressure: At warm idle, pressure ranges
from 1.0-1.5 bar (14-22 psi). Under load, the variable displacement pump
maintains pressure between 3.0-4.5 bar (44-65 psi) based on demand.
Oil Cooler: Liquid-to-oil plate-type heat exchanger integrated into the oil
filter housing, utilizing engine coolant for thermal stabilization. Oil Filter:
Cartridge-type filter housed within a modular housing accessible from the engine
top or under-vehicle location. Crankcase Ventilation: Closed PCV system with an
integrated oil separator incorporated into the valve covers.
The cooling system is pressurized and utilizes a
centrifugal water pump driven by the timing chain. Water Pump Type: Centrifugal
pump with a die-cast aluminum housing and stamped steel impeller. Thermostat:
Wax-pellet type with integrated housing. Opening temperature is 82-88 °C
(180-190 °F). Full opening occurs at 95 °C (203 °F).
Coolant Capacity: 7.0-7.8 liters (7.4-8.2 qt) inclusive of engine block, heater
core, and radiator. Radiator: High-efficiency aluminum cross-flow core with
plastic end tanks. Cooling fan configuration consists of dual electric fans with
variable speed control based on coolant temperature and air conditioning load.
System Pressure: Radiator cap rated at 1.1 bar (16 psi). Coolant Specification:
Phosphate and silicate-free ethylene glycol-based coolant meeting Nissan
specifications for aluminum engine construction.
Ignition System: Direct ignition system with individual
pencil-type ignition coils mounted directly over each spark plug (coil-on-plug).
The system utilizes a crankshaft position sensor and dual camshaft position
sensors for sequential ignition timing. Spark Plug Type: NGK PLFR5A-11 or
equivalent (platinum-tipped for extended service). Spark Plug Gap: 1.0-1.1 mm
(0.039-0.043 in).
Timing System: Maintenance-free timing chain system with a single roller chain
driving the intake camshafts on both banks from the crankshaft. A secondary
chain on each bank transmits drive from the intake camshaft to the exhaust
camshaft. Hydraulic chain tensioners supplied by the engine lubrication circuit
maintain tension. The system is intended for the engine service life.
Exhaust System: Cast stainless steel exhaust manifolds with individual
collectors per bank, merging into a single exhaust pipe downstream. A dual
catalytic converter system (one per bank) is utilized with oxygen sensors
positioned before and after each catalyst.
Intake System: Air induction utilizes a large-volume air cleaner housing with a
resonator to reduce induction noise. The throttle body incorporates an
electronically controlled idle air control system.
Emission Control: Exhaust Gas Recirculation (EGR) system recirculates a portion
of exhaust gases to the intake manifold to reduce NOx emissions. The system is
controlled by the engine control unit based on engine speed and load.
Overall Length: 630 mm (24.8 in) measured from
accessory drive pulley face to transmission mounting flange.
Overall Width: 680 mm (26.8 in) inclusive of intake manifold, throttle body, and
exhaust manifold heat shields.
Overall Height: 690 mm (27.2 in) from oil pan bottom surface to valve cover top
surface.
Dry Weight: 140-150 kg (309-331 lb) depending on intake manifold configuration
and accessory drive components.
Timing Chain Inspection: Chain, tensioners, and guides
inspection recommended at 120,000 km (75,000 miles). Replacement is
condition-based. Spark Plug Replacement Interval: 100,000 km (60,000 miles) for
platinum-tipped plugs. Drive Belt Tension (Accessory): Automatic tensioner
maintains correct tension; no manual adjustment required. Belt replacement
interval is 80,000 km (50,000 miles). Coolant Change Interval: 80,000 km (50,000
miles) or 4 years.
Engine Oil Change Interval: 10,000 km (6,200 miles) or 12 months for standard
driving conditions; 5,000 km (3,100 miles) for severe service. Idle Speed (warm,
neutral): 650-700 rpm. Injection Timing: Electronically controlled with
closed-loop feedback from oxygen sensors; no manual adjustment possible. Fuel
Pressure (low-pressure circuit): 3.0-4.0 bar (44-58 psi). High-pressure rail
pressure varies from 30-40 bar (435-580 psi) at idle to 120-140 bar (1,740-2,030
psi) under full load.
Cylinder Head Bolts (cold): 30 Nm (22 lb-ft).
Crankshaft Damper Pulley Bolt: 180-200 Nm (133-148 lb-ft).
Connecting Rod Cap Bolts: 20 Nm (15 lb-ft).
Main Bearing Cap Bolts (bedplate-to-block): 25 Nm (18 lb-ft).
Camshaft Bearing Cap Bolts: 12-15 Nm (9-11 lb-ft).
Camshaft Sprocket Bolts: 90-100 Nm (66-74 lb-ft).
Valve Cover Bolts: 8-10 Nm (6-7 lb-ft).
Intake Manifold Bolts: 20-25 Nm (15-18 lb-ft).
Exhaust Manifold Nuts: 25-30 Nm (18-22 lb-ft).
Oil Pan Bolts: 10-12 Nm (7-9 lb-ft).
Timing Chain Tensioner Bolts: 20-25 Nm (15-18 lb-ft).
Timing Chain Guide Bolts: 20-25 Nm (15-18 lb-ft).
Water Pump Bolts: 20-25 Nm (15-18 lb-ft).
High-Pressure Fuel Pump Mounting Bolts: 20-25 Nm (15-18 lb-ft).
Fuel Injector Clamp Bolts: 25-30 Nm (18-22 lb-ft).
Flywheel / Drive Plate Bolts: 90-100 Nm (66-74 lb-ft).
Spark Plugs: 20-25 Nm (15-18 lb-ft).
Nissan Skyline (V35 series): 2001-2006. The VQ25DD
powered the 250GT and 250GT Four variants of the V35 Skyline sedan and coupe,
providing the entry-level V6 powertrain above the inline-four QR25DE. This
application utilized the 11.3:1 compression ratio calibration with 212 hp (158
kW).
Nissan Cefiro (A33 series): 1999-2002. The VQ25DD was introduced in the A33
Cefiro as the NEO Di variant, positioned as the premium gasoline powertrain in
the Japanese Domestic Market. This application utilized a 11.0:1 compression
ratio with 207 hp (154 kW).
Nissan Cedric / Gloria (Y34 series): 1999-2004. The VQ25DD served as the base V6
powertrain for the Cedric and Gloria luxury sedans, replacing the older VQ25DE
in these applications. The engine was paired exclusively with a four-speed or
five-speed automatic transmission.
Nissan Stagea (M35 series): 2001-2007. The VQ25DD powered the 250T and 250T RS
variants of the Stagea wagon, offering direct-injection efficiency in a
performance-oriented estate body style.
Nissan Fuga (Y50 series): 2004-2007. The VQ25DD was installed in the base 250GT
and 250GT Four variants of the Fuga luxury sedan, continuing the
direct-injection V6 lineage in the Y50 platform. This application utilized the
higher 11.3:1 compression ratio calibration.
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