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Nissan RB, released from 1985 to 2004, is a 2.0-3.0L inline-six four-stroke gasoline motor.
The aluminum head is applied for both single and dual overhead camshaft versions. Single overhead camshaft motors keep two valves per cylinder while the ones with dual overhead camshaft feature four valves per cylinder. Each camshaft lobe controls just one valve. RB motors are supplied with belt-driven camshafts plus cast iron blocks.
Models with turbocharging keep an inter-cooled turbo (except RB20ET and RB30ET with SOHC) along with recirculating factory blow-off valve (except motors employed for Laurel and Cefiro models). The latter deals with compressor surge reduction when the throttle closes fast.
RB motors are built on the framework of 6-cylinder L20A engines, keeping identical bore and stroke. Mainly, the brand’s factory in Yokohama, Japan, which deals with the production of VR38DETT today, released these motors. Additionally, some motors were produced by the NISMO department at the Omori Factory in Tokyo, where Z-Tune Skylines were also remodelled.
Nissan RB20 Engine Review
The debut version of RB lineup, RB20, was released in 1984. Being built as an alternative to L20, RB20 became the smallest motor of the range. Moreover, it was available in various modifications.
RB20E, the primary variation launched in 1984, was a cast-iron inline-six motor, featuring an aluminum head with one camshaft plus two valves per cylinder. It reached an output of 115-130 hp, depending on the year of production. It didn’t become too famed and, actually, it was rather ordinary.
In 1985, RB20ET, a version with turbocharging, was presented. Keeping boost pressure of 7 psi (0.5 bar), it wasn’t provided with an intercooler. Its output was 170 hp, but some models couldn’t exceed the power of 145 hp.
The same year, the best-selling model, RB20DE, was introduced. It differed from the previous version by its restyled head, keeping 2 camshafts plus four valves per cylinder. Moreover, it featured individual ignition coils, redesigned crankshaft, restyled connecting rods, pistons plus an inlet system along with fresh ECU.
Characteristics of camshafts were the following: duration 232/240 degrees and lift 7.3/7.8 mm. Output was 150-165 hp. Such motors were employed for Nissan Skyline R31/R32, Cefiro A31 plus Laurel C33/C34. This motor folded valves in case of timing belt damage.
In 2000, RB20DE was subjected to some updates, comprising fresh crankshaft, enhanced inlet system, restyled head without hydraulic lifters plus new ECU. Being named RB20DE NEO, it was more eco-friendly and had the power of 155 hp. Nissan Skyline R34, Stagea C34 plus Laurel C35 utilized RB20DE NEO motors.
Again in 1985, Nissan released RB20DET, a version with turbocharging. Using a 16V turbocharger, it reached a boost pressure of 7 psi (0.5 bar). Furthermore, fresh pistons, connecting rods, restyled camshaft, cylinder head seal, ECU and 270 cc fuel injectors were installed. These alterations contributed to a lower compression index equal to 8.5. RB20DET Red top models, employed for Skyline R31, had NICS intake system.
RB20DET camshafts had duration 248/240 degrees and lift 7.8/7.8 mm. Consequently, this modification was able to reach 180-190 hp, depending on the model.
RB20 Engine Specs
|Also called||Nissan RB20|
|Cylinder block alloy||Cast-iron|
4 valves per cylinder
2 valves per cylinder
|Piston stroke, mm (inch)||69.7 (2.74)|
|Cylinder bore, mm (inch)||78 (3.07)|
|Compression ratio||10.0 (RB20DE)
|Displacement||1998 cc (121.9 cu in)|
|Power output||85 kW (115 HP) at 5,600 rpm
92 kW (125 HP) at 5,600 rpm
96 kW (130 HP) at 5,600 rpm
107 kW (145 HP) at 6,000 rpm
110 kW (150 HP) at 6,400 rpm
114 kW (155 HP) at 6,400 rpm
121 kW (165 HP) at 6,400 rpm
125 kW (170 HP) at 6,000 rpm
132 kW (180 HP) at 6,400 rpm
140 kW (190 HP) at 6,400 rpm
158 kW (215 HP) at 6,400 rpm
|Torque output||167 Nm (123 lb·ft) at 4,000 rpm
172 Nm (127 lb·ft) at 4,400 rpm
181 Nm (133 lb·ft) at 4,000 rpm
206 Nm (151 lb·ft) at 3,200 rpm
181 Nm (133 lb·ft) at 5,200 rpm
184 Nm (136 lb·ft) at 5,200 rpm
186 Nm (137 lb·ft) at 5,600 rpm
216 Nm (159 lb·ft) at 3,200 rpm
226 Nm (167 lb·ft) at 3,600 rpm
240 Nm (177 lb·ft) at 4,800 rpm
265 Nm (195 lb·ft) at 3,200 rpm
|HP per liter||57.6
|Weight, kg (lbs)||230 (507) – RB20DE
245 (540) – RB20DET
|Fuel consumption, L/100 km (mpg)
|for Fairlady 200ZR
|Turbocharger|| Naturally aspirated
|Oil consumption , L/1000 km
(qt. per miles)
|up to 0.5
(1 qt. per 1200 miles)
|Recommended engine oil||0W-30
|Engine oil capacity, L (qt.)||4.2 (4.4)|
|Oil change interval, km (miles)||5,000-10,000
|Normal engine operating temperature, °C (F)||90 (195)|
|Engine lifespan, km (miles)
-No life span loss
In 1988, these motors gained ECCS system plus fresh camshafts and were named RB20DET Silver top. Camshafts had duration 240/240 degrees and lift 7.8/7.8 mm and led to output of 215 hp at 6,400 rpm.
In 1993, Nissan ceased the production of RB20DET and substituted it with RB25E, a naturally aspirated motor with identical power.
Good news: the owners of RB20DE and RB20DETmotors don’t need to adjust the valves. However, the valves at RB20DE NEO require regulation periodically. Every RB20 motor features a timing belt, which requires substitution after every 60,000 miles (90,000 kilometers) are run. In addition to RB20, RB range also comprised RB24S, RB25DE/DET, RB26DETT plus RB30S/E/ET motors.
After the production of RB20DE/E was ceased, VQ23DE became its alternative.
- Nissan Skyline
- Nissan 200ZR
- Nissan Stagea
- Nissan Cefiro
- Nissan Crew
- Nissan Laurel
- Holden Commodore
RB20 Engine Problems and Reliability
RB20 motors stand out from the rest by their great reliability and long lifespan. If to maintain it properly and use only high-quality fuel and oil, you will be able to run for 200,000-250,000 miles (300,000-400,000 kilometres) with no troubles. However, if you do some tuning, the lifespan can be shorter.
Nevertheless, the blindsides of these motors are ignition coils, which failure may cause a misfire. So, it’s important to replace them after every 60,000 miles (100,000 kilometers). Another minus is the high level of fuel consumption.
Nissan RB20 Tuning Options
Though this motor has many advantages, it’s still not perfect. Thus, you may notice the lack of proper torque under 4,500 rpm. However, it can be resolved in several ways, the most popular of which is the mounting of aftermarket camshafts and a bigger turbocharger. If you aren’t ready for huge money investments, you are free to install mild camshafts, leaving the original turbocharger. Not significantly, but the power boost will be evident.
Oil system is another weak point as the failure of ignition coils may lead to misfire. But if to compare this motor with other similar models, it seems to be almost trouble-free.
If you want to add some updates to your RB20 motor, you have rather a vast number of options. Thus, Garrett and HKS turbochargers allow reaching boost pressure of 11.5 psi. For instance, HKS Sport Turbo range is great for output enhancement. Or, 2530kai may increase the power to 350-360 hp. Moreover, such an output can be achieved by ECU tuning and upgrading of camshafts. Or, 2530 turbocharger, which is a bit smaller, increases output without any major changes. By simply placing it instead of the original one, you will gain some power boost plus a motor with greater level of responsiveness.
Garrett, which provides turbochargers for original Nissan motors, offers some alternatives as well. The cooperation of two brands makes a great number of Garrett turbochargers suitable for Nissan engines. However, it’s crucial to consider the exact type of motor as only the proper size turbo will lead to the maximum output.
But turbochargers aren’t the only elements, which can be added to your motor. Thus, pay attention to a turbo booster kit by Trust. Its mounting is super easy as it features a bolt-on design. Besides a turbocharger, the kit also comprises seals, lines, a wastegate plus fresh manifold. Some kits may also have some other components to make the installation simple and fast. TD06-20G is one of the most appropriate kits for RB20DET motors.
Additionally, the motor performance can be enhanced by fuel injectors, GTR intercooler, downpipe, 3-inch straight pipe exhaust system, spark plugs, turbo boost controller plus fuel pump. Walbro 255 and GTR brands are decent options for fuel pumps. Meanwhile, MLS head seals, head studs and restyled camshafts allow reaching 450 hp.
RB20 vs RB25
Actually, RB25 turned out to be more efficient and powerful than its predecessor. This range consists of four motors, two with twin camshafts plus turbocharger and two with twin camshafts but without turbocharger.
Unlike RB20, RB25 motors are able to allow Nissan automobiles to reach greater power and torque at lower rpm. Such an enhancement was achieved thanks to ignition coils featuring integrated ignitors, a restyled airflow meter, throttle position sensor plus some other updates. In 1998, the motor was supplied with ahead, which led to a lower emission rate.