The difference between RB25 and RB26 engines is in terms of their power capacities and performances. The former 2.5 L engine boasts a power range of 182-203 PS at 6000 rpm and a torque of 255 N.m at 4000 rpm.
While the latter is a much more powerful version- owing to the numerous electrical, mechanical and technical improvements incorporated into this version. The 2.6 L RB26 engine operates at an enhanced power capacity of 280 PS at 6,800 rpm and a torque of 353 N.m at 4000 rpm.
The turbochargers offer enhanced performativity to the RB26 engine model.
Comparison Table Between RB25 and RB26
| Parameters of Comparison | RB25 | RB26 |
| Power Capacity | RB25 engines operate at a power capacity of 182-203 PS at 6000 rpm and a torque of 255 N.m at 4000 rpm. | RB26 engines operate at a power capacity of 280 PS at 6,800 rpm and a torque of 353 N.m at 4000 rpm. |
| Engine Capacity | 2.5 L engine capacity with a stroke of 71.7 mm. | 2.6 L engine capacity and a stroke of 73.7 mm. |
| Lifters | Hydraulic lifters. | Solid lifters. |
| Throttle Bodies | Single throttle body. | Six throttle body. |
| Turbo Power | Non-turbo (initial version) | Twin turbo-powered engine. |
| Cost | Lower than RB26 engines. | Higher than RB25 engines. |
What is RB25?
RB25 engines were introduced by Nissan in 1993 as a part of its coveted RB series specifically for the Nissan Skyline GTST R33. The RB25 engine was an improvement over its RB20DET predecessor.
This new range featured 2.5 L, 2498cc engines and witnessed a number of improvements that were rolled out in the subsequent years.
RB25DE was the initial model that was designed as a twin-cam and non-turbo engine featuring a 10:1 compression ratio. These engines boasted a power capacity of 182-203 PS at 6000 rpm and a torque of 255 N.m at 4000 rpm. Thus, the new model was an improvement on the power capacity of its predecessor at a lower rpm.
Two other updated versions of the RB25 were launched in the following years. The update for RB25 engine was launched in 1995 when Nissan announced the release of series 2 RB25DET engines in this range. The update featured an advanced turbocharger and electric system.
Ignition coils were also introduced in this improved version of the RB25 engine. Finally, in 1998 the RB25DET NEO was introduced with further revisions specifically for Nissan Skyline R34. This version was marketed as a low emission engine that significantly reduced fuel consumption.
What is RB26?
The RB26 engines were in wide circulation from 1998-2002. The RB26DETT line featured 2.6 L inline-six engines. They were primarily used in the Nissan Skyline GT-R. The single throttle body used in its predecessors was replaced by six individual throttle bodies in this new model.
The RB26 DETT engine is often entitled as the king of engines in the Nissan RB engine range. Implementing T-25 ceramic turbochargers, the engine has a twin-turbo system.
The highest recorded power level post-production was 280 PS at 6,800 rpm and a torque of 353 N.m at 4000 rpm. This is a remarkable improvement over its predecessor’s power capacity.
Other features of this engine line include belt-driven cams, sodium filed exhaust valves and solid lifter valves. This famed engine line was modified with the release of RB26 DETT N1 that improved this powerful engine design further. Recently Nissan announced its decision to resume production of the RB26 engines.
Main Differences Between RB25 and RB26
- The main difference between RB25 and RB26 is in terms of the power capacity of each engine version. The former has a capacity of 182-203 PS at 6000 rpm and a torque of 255 N.m at 4000 rpm. While the latter operates at a capacity of 280 PS at 6,800 rpm and a torque of 353 N.m at 4000 rpm.
- The former version boosts a 2.5L engine capacity with a stroke of 71.7 mm. The latter is empowered by a 2.6 L engine capacity and a stroke of 73.7 mm. This makes the RB26 version is more powerful than the RB25 model.
- Another difference can be noted in terms of the lifters featured by each version. While RB25 engines operate on hydraulic lifters, the improved RB26 version uses solid lifters.
- The RB25 engines used a single throttle body, whereas its successor- the RB26- operates on 6 throttle bodies.
- The initial RB25 model was a non-turbo engine, although turbochargers were added in the subsequent updated versions. The RB26 operates on a twin-turbo system that makes them much more effective and powerful than its RB25 predecessor.
- The comparative cost of the RB25 model is lesser than the RB26 version. The additional updates make the RB26 model more costly than its predecessor.
Conclusion
The famed Nissan Skyline engine models were widely appreciated by car enthusiasts globally for their low fuel consumption, top-of-the-line features and superior quality. However, there exist subtle differences between each version launched by the brand.
The RB25 engines were a class apart from their predecessors both in terms of power as well as built. This design was further improved in the updates rolled out in the subsequent years. However, the RB26 model revolutionized the engine market.
The turbochargers empowered enhanced power capacity, solid lifters, enhanced electrical mechanics, 6 throttle bodies and other improved features made this engine significantly different from the RB25 version.
The non-turbo RB25 version was different from this model in several ways including lower power capacity, hydraulic lifters and single throttle body.
The RB26 engine was priced at a higher price limit than RB25 models, owing to the electrical and composite improvements. Although both are powerful and effective models, the RB26 model is the more optimized choice.
