The 2.5-liter turbo engine Nissan RB25DET was produced from 1993 to 2004 in Japan and put on models with a sporty character, such as Skyline, Gloria, Leopard and others. After modernization in 1998, the improved version of the engine received the addition of NEO in the name.
The 2.5-liter Nissan RB25DE engine was produced from 1991 to 2002 at the Japanese factory and was installed on such popular models as Skyline, Cefiro, Laurel, and Steija. Since about 1998, a modernized version of this motor with the prefix NEO is produced.
Characteristics of RB25DET/DE engine
| Characteristics | RB25DET (Standard version) | RB25DE (Standard Modification) | RB25DE NEO | RB25DET NEO |
|---|---|---|---|---|
| Precise volume | 2498 cm³ | 2498 cm³ | 2498 cm³ | 2498 cm³ |
| Power System | Distributed injection | Distributed injection | Distributed injection | Distributed injection |
| Power | 235 – 250 hp | 180 – 190 hp | 200 hp | 280 hp |
| Torque | 275 – 320 Nm | 225 – 235 Nm | 255 Nm | 335 – 365 Nm |
| Cylinder block | Cast iron R6 | Cast iron R6 | Cast iron R6 | Cast iron R6 |
| Block head | Aluminum 24v | Aluminum 24v | Aluminum 24v | Aluminum 24v |
| Cylinder diameter | 86 mm | 86 mm | 86 mm | 86 mm |
| Piston stroke | 71.7 mm | 71.7 mm | 71.7 mm | 71.7 mm |
| Compression ratio | 8.5 | 10 | 10 | 9.0 |
| Features | No | No | No | No |
| Hydrocompensators | Yes | Yes | No | No |
| Transmission of the timing belt | Belt | Belt | Belt | Belt |
| Fasoregulator | Option | Option | On Inlet NVCS | NVCS Inlet |
| Turbocharging | Turbo 45V1 or 45V2 | No | No | Turbine 45V3 or 45V4 |
| Recommended Oil | 4.7 liters 5W-30 | 4.6 liters 5W-30 | 4.6 liters 5W-30 | 4.7 liters 5W-30 |
| Environmental class | EURO 2/3 | EURO 2/3 | EURO 3/4 | EURO 3/4 |
| Example service life | 370,000 km | 400,000 km | 350,000 km | 320,000 km |
| Engine weight | 260 kg | 235 kg | 235 kg | 260 kg |
Vehicles with these engines
| Car | Engine | Years of manufacture |
|---|---|---|
| Nissan Cedric 9 (Y33) | RB25DET | 1997 – 1999 |
| Nissan Cedric 10 (Y34) | RB25DET | 1999 – 2004 |
| Nissan Gloria 10 (Y33) | RB25DET | 1997 – 1999 |
| Nissan Gloria 11 (Y34) | RB25DET | 1999 – 2004 |
| Nissan Laurel 6 (C33) | RB25DE | 1991 – 1993 |
| Nissan Laurel 7 (C34) | RB25DE | 1993 – 1997 |
| Nissan Laurel 8 (C35) | RB25DE | 1997 – 2002 |
| Nissan Skyline 8 (R32) | RB25DE | 1991 – 1994 |
| Nissan Skyline 9 (R33) | RB25DE | 1993 – 1998 |
| Nissan Skyline 10 (R34) | RB25DE | 1999 – 2002 |
| Nissan Cefiro 1 (A31) | RB25DE | 1991 – 1994 |
| Nissan Stagea 1 (WC34) | RB25DE | 1996 – 2001 |
| Nissan Leopard 4 (Y33) | RB25DE | 1996 – 1999 |
Design and repair of RB25DET/RB25DE engine
The most famous and very popular representative of the RB series with a working volume of 2.5 liters appeared in 1991, as a replacement for the RB20DET. At that time, the new RB25DE used a cylinder block similar to the RB20, but with increased cylinder bore to 86 mm, crankshaft, with a piston stroke of 71.7 mm, used other connecting rods and pistons. The cylinder head is twin-shaft, 24-valve. The first models (up to 1993) were not equipped with NVCS. Characteristics of camshafts on these engines: phase 240/232, lift 7.8/7.3 mm. These RB25DE S1 (Series 1) engines developed 180 hp at 6000 rpm. Later, in 1993 (with the release of the Skyline R33), the NVCS system on the intake shaft was introduced, and the exhaust camshaft was replaced with a 240, 7.8mm lift. The power output of these cars with the RB25DE increased to 190 hp at 6400 rpm. Since 1995, the ignition system, maf, camshaft position sensor, engine control unit were changed.
In 1998, a new generation of RB25DE NEO appeared on the Nissan Skyline R34. This motor met high ecological standards, and was equipped with a new intake manifold with thin runners, modified cylinder head with modified combustion chambers, without hydrocompensators, with new camshafts (phase 236/232, lift 8.4/6.9 mm), another exhaust manifold. Power of RB25DE NEO engine increased to 200 hp at 6400, torque 231 Nm at 4800 rpm.
Along with the atmospheric engine, the most famous turbo modification RB25DET was also produced. The first version (RB25DET S1) appeared in 1993, on the Nissan Skyline R33 and from the usual RB25DE S1 differed by connecting rods, pistons for compression ratio of 8.5, the presence of a turbocharger 45V1 (larger than RB20DET), operating at a pressure of 0.5 bar. This version was equipped with a variable valve timing system on the intake camshaft NVCS, 370 cc/min injectors, and oil injectors are installed in the cylinder block. Power of such engine is 245-250 hp at 6400 rpm, torque 272 Nm at 4800 rpm.
Similar to the RB25DE, a restyling was carried out in 1995, during which the ignition system, maf, camshaft position sensor, control unit were changed. The turbine was replaced by a 45V2, where a plastic impeller is used instead of a steel impeller. Such engines are called RB25DET S2.
In 1998, the engine was modified and called RB25DET NEO. Such engines met higher environmental standards and differed by crankshaft, connecting rods from RB26DETT, pistons, increased to 9 compression ratio, cylinder block with oil injectors and without oil duct. Other differences: intake manifold (split), modified cylinder head with modified intake ducts and combustion chambers, rigid tappets instead of hydrocompensators. RB25DET NEO engines use camshafts with 236/232 phase, 8.4/8.7 mm lift and 340 cc injectors. Neo motors use a 45V3 turbocharger with a larger hot end and plastic impeller, boost pressure increased to 0.7 bar. All these modifications made it possible to remove 280 hp at 6400 rpm, torque 334 Nm at 3200 rpm. Later, from 2001, a 45V4 turbine, with a steel impeller, was put in.
There is no need to adjust the valves on RB25DE/DET, these power units are equipped with hydrocompensators, except for NEO versions. RB25DET/DE uses timing belt, timing belt life is 80-100 thousand kilometers.
Together with RB25DE/DET, the RB series included RB20E/ET/DE/DET, RB24S, RB26DETT and RB30S/E/ET.
After the RB25 was discontinued in 2002, it was replaced by the V6 VQ25DE/DET.
Nissan RB25DET/DE engine problems and shortcomings
Like many legendary motors of the 90s, the RB series is very reliable, not for nothing it is one of the most famous in the world. These engines are free of design flaws and major problems. Of the more minor troubles, we can note the periodic failure of ignition coils, which leads to trojan. Change them after 100 thousand kilometers and everything will be fine. Also, Nissan RB motors are characterized by high fuel consumption.
Otherwise, RB engines are quite reliable and durable, if you do not make a booster, regular maintenance and use quality oil and gasoline.
Comparing RB25DET with 1JZ-GTE, the closest competitor of Nissan motor, we can say that the design of 1JZ is a bit more successful, and in general the motor is a bit more reliable and more adapted to tuning.
Tuning Nissan RB25DET engine
RB25DET Boost Up
It is worth to put RB25DE tuning or RB25DE turbocharging out of your mind at once, it is much easier, faster, more reliable and cheaper to buy a contract RB25DET and get high power at once.
The limit of stock turbos on RB25DET is 0.8-0.9 bar, there is no sense to go further. At 0.9 bar, with 76mm exhaust, GTR front intercooler, Apexi power intake, MAF Z32, boost controller, new plugs, pump and oil pump from GTR N1, oil cooler, Walbro 255 lph pump, Apexi Power FC (or with another brain), you will get about 300hp at the wheels. That will allow you to go 1/4 mile in an average of 13 sec. That’s not enough for everyone, so we move on.
And next you need to replace the stock turbo with a HKS GT2835, buy 550 cc injectors, fuel regulator, Splitfire coils, 3 ply radiator. Then blow 1 bar and take off about 340hp at the wheels, at 1.5 bar get about 400hp.
More power can be made with a GT3540 turbo, with 256/256 camshafts and 750 cc injectors, this will give a chance to get about 400hp at the wheels at 1 bar of boost. With a turbo like that, you can go the quarter mile in the high 11 secs.
You can blow 500 hp in a stock piston, and with methanol and more, but it is better to buy GTR connecting rods, forged pistons, steel cylinder head gasket, ARP studs, make porting and then already blow 500+ hp.
In addition to boost and installation of turbos on RB25DET periodically practiced installation of RB26DETT. There are also variants with stroker kit (larger diameter pistons with long stroke crankshaft) up to 2.8-2.9 liters or up to 2.6 liters by installing crankshaft and pistons RB26DETT plus 1.2 mm cylinder-head gaskets. All of this is already expensive, complicated and unnecessary. In such cases, sell your RB25DET and buy an RB26DETT engine.
MOTOR RATING: 5-