Popular models like the Skyline, Cefiro, Laurel, and Stage were equipped with the 2.5-liter Nissan RB25DE engine, which was manufactured at a Japanese facility between 1991 and 2002. Up until 1993, the NVCS variable valve timing system was absent from the initial models. These engines’ camshafts have phase 240/232 and rise 7.8/7.3 mm. At 6000 rpm, the RB25DE S1 (Series 1) produced 180 horsepower. With the introduction of the Skyline R33 in 1993, NVCS was added to the intake shaft, and a 240, 7.8 mm lift took the place of the exhaust cam. At 6400 rpm, power rose to 190 horsepower. The engine control unit, camshaft position sensor, maf, and ignition system have all been modified since 1995.
From 1993 to 2004, the Nissan RB25DET 2.5-liter turbo engine was manufactured and installed on sporty models like the Skyline, Gloria, Leopard, and others. The original RB25DET S1, which debuted in 1993 on a Nissan Skyline R33, was different from the standard RB25DE S1 in that it had connecting rods, pistons for an 8.5 compression ratio, and a 45V1 turbocharger running at 0.5 bar of pressure. This version had 370 cc/min injectors, oil nozzles in the cylinder block, and a variable valve timing system on the NVCS intake camshaft. 245–250 horsepower at 6400 rpm and 272 Nm of torque at 4800 rpm. In 1995, the RB25DE underwent a restyling that included changes to the control unit, maf, ignition system, and camshaft position sensor. The turbine was swapped out for a 45V2, which uses a plastic impeller rather than a steel one. These engines are known as RB25DET S2.
Upgraded models bearing the NEO prefix have been manufactured since roughly 1998. A lot has been updated, and these engines also complied with stricter environmental regulations.
Specifications
| Production years | 1991-2002 (RB25DE) 1993-2004 (RB25DET) |
| Displacement, cc | 2498 |
| Fuel system | distributed injection |
| Power output, hp | 180 – 190 (RB25DE) 235 – 250 (RB25DET) |
| Torque output, Nm | 225 – 235 (RB25DE) 275 – 320 (RB25DET) |
| Cylinder block | cast iron R6 |
| Block head | aluminum 24v |
| Cylinder bore, mm | 86 |
| Piston stroke, mm | 71.7 |
| Compression ratio | 10 (RB25DE) 8.5 (RB25DET) |
| Features | no |
| Hydraulic lifters | yes |
| Timing drive | belt |
| Phase regulator | optional |
| Turbocharging | no (RB25DE) turbine 45V1 or 45V2 (RB25DET) |
| Recommended engine oil | 5W-30 |
| Engine oil capacity, liter | 4.6-4.7 |
| Fuel type | petrol |
| Euro standards | EURO 2/3 |
| Fuel consumption, L/100 km (for Nissan Skyline 1997) — city — highway — combined |
14.4 9.8 12.0 |
| Engine lifespan, km | ~400 000 |
| Weight, kg | 235 (RB25DE) 260 (RB25DET) |
Specifications of the NEO modification
| Displacement, cc | 2498 |
| Fuel system | distributed injection |
| Power output, hp | 200 (RB25DE) 280 (RB25DET) |
| Torque output, Nm | 255 (RB25DE) 335 – 365 (RB25DET) |
| Cylinder block | cast iron R6 |
| Block head | aluminum 24v |
| Cylinder bore, mm | 86 |
| Piston stroke, mm | 71.7 |
| Compression ratio | 10 (RB25DE) 9 (RB25DET) |
| Features | no |
| Hydraulic lifters | no |
| Timing drive | belt |
| Phase regulator | at the NVCS inlet |
| Turbocharging | no (RB25DE) turbine 45V3 or 45V4 (RB25DET) |
| Recommended engine oil | 5W-30 |
| Engine oil capacity, liter | 4.6-4.7 |
| Fuel type | 92 |
| Euro standards | EURO 3/4 |
| Engine lifespan, km | ~330 000 |
Disadvantages of the RB25 engine
One of the most widely used inline six-cylinder engines is well known for its outstanding dependability;
Owners primarily complain about their engine’s high fuel consumption;
Tripping is caused by the short lifespan of ignition coils;
The valve bends when the timing belt breaks, so don’t skip the replacement process;
Bad gasoline is disliked by the fuel system, and injectors clog easily.