What is an RB engine?

If you’re into JDM cars you’ve most likely heard of the term ‘RB’, or “RB engine“. The term RB is thought to mean ‘Race-bred’ or, ‘Rhythm & Balance’ and is the engine code for the RB-engine series. The RB series was introduced in 1985 by Nissan and was developed up until 2004. Although production for the RB26 variant started again in 2019.

RB engines ranged from 2.0-3.0 liter straight-6 four-stroke gasoline engines. The engine itself was derived from the six-cylinder Nissan L20a engine, which shared its bore and stroke size with the first RB engine, the RB20. RBs have an aluminum head, belt-driven cams, and a cast-iron block. The turbo models have an inter-cooled turbo with the exception of the RB20ET and RB30ET variants

RB Meaning

The RB engine came with different numbers and designations which were used to identify the engine’s displacement and features.

Indentification	Displacement	(Bore x stroke)
RB20	2.0 L (1,998cc) I6	78 mm x 69.7 mm
RB24	2.4 L (2,428 cc) I6	86 mm x 69.7 mm
RB25	2.5 L (2,498 cc) I6	86 mm x 71.7 mm
RB26	2.6 L (2,568 cc) I6	86 mm x 73,7 mm
RB30	3.0 L (2,962 cc) I6	86 mm x 85 mm

Variants	Meaning
D	Dual overhead cam
E	Electronically fuel-injected
S	Carbureted
T	Turbocharged
TT	Twin-Turbocharged
P	The engine runs on LPG (Liquefied petroleum gas)

Power in the RB series ranged from 94-500 PS (69-368 kW; 93-493hp) and torque ranged from 142-540 Nm (105-399 lb. ft).

Nissan RB-Engine Racing History

The RB engine has an unformidable racing history. The 1989 Nissan Skyline GT-R was introduced to racing motorsports in 1990 and took on the likes of BMW, Ford, and Holden V8. The 1989 Skyline was powered by the RB26DETT and unlike its rivals had a four-wheel-drive system. In Race-trim the GT-R amassed an incredible 600 horsepower even with the 4-wheel-drive system it only clocked in at about 1260 kg.

The Skyline was really, really, really good.

There is no other way to put it, the 1989 Nissan Skyline was so good it was nicknamed ‘Godzilla’ by the Australian motor press. The GT-R completely demolished the competition between 1990-1992 in both the Group A Championship, placing 1^st three times in a row, and also securing two wins in the Bathurst 1000. What kept it from winning anymore, was its own success. The 1989 Nissan GT-R was eventually banned from motorsports due to its clearly superior 4-wheel-drive system, instant power, and low weight.

RB Engine Series

RB20

The RB20 was the very first engine in the RB series and was using the same bore and stroke sizes as its older sibling the L20A engine. However, most components were changed from the older designed engine. The RB20 came as a 2.0-liter (1998 cc) engine and produced in its least powerful form 93hp all the way up to its most powerful, 212hp. Both single (SOCH) and dual (DOHC) overhead camshafts were available for the RB20.

RB20 Engine Variations:

RB20P

The RB20P was probably one of the rarest engine variations on this list. Because it utilized LPG (liquefied petroleum gas) it only managed to achieve a mere 93hp output. This variation also only came with SOHC (single overhead camshaft).

RB20E

The RB20E was the first engine in the RB series, it was electronically fuel-injected and featured SOCH technology. Depending on the year of the production, power output varied between 129-148hp.

RB20ET

This was the upgraded version of the RB20E and was turbocharged boosting its power output to 145-175 hp. Alike the RB20E the turbo-version also featured SOHC technology.

RB20DE

This version was the first in the RB-series to feature dual overhead camshafts (DOHC) technology. This non-turbo version managed a power output of between 148-153 hp-

RB20DET

As you might have guessed the RB20DET utilized the same ingredients as the RB20DE except It also came with a turbocharger. However, it also came with new fuel injectors, connecting rods, and pistons – this allowed the RB20DET to produce around 220hp at peak power.

RB20DET-R

This engine was the race-version of the RB20DET. Its specification was very similar to the RB20DET but was more focus-oriented to work optimal at high revolutions. That means that the race-version was not really fitted for daily use as it often felt ‘sluggish’ and unresponsive when driven “normally”.

RB20DE NEO

Very similar to the RB20DE the NEO version was the eco-friendlier variant. Peak power was slightly lower at around 150-160 hp.

Used in: Nissan Laurel, R32 Skyline, Nissan Cefiro, HR31 Skyline, Nissan Fairlady 200ZR.

RB24

The RB24 is the Frankenstein of the RB series, which also made it the rarest. The RB24 was built by using parts from different RB engines. Because this engine was not built for the Japanese market the supply for these engines was kept short.

The cylinder head was from the RB30, the crankshaft was from the RB20DE(T), and the engine block from an RB25DE(T) – combined this build revved higher than its counterparts, but the power output still stayed modest at around 140 hp.

RB25

The 2.5-liter version of the RB engine all featured dual overhead camshaft technology.

RB25DE

Alike the RB20DE, this version also featured DOHC technology. Thanks to more developed components and higher displacements the RB25DE managed to push out 175hp in its earliest form, and as development went along, power output increased to 210 hp.

RB25DET

This was the turbocharged variant of the RB25DE and increased power output to 240-250hp.

RB25DE-NEO

The NEO version was the eco-friendlier variant. Peak power output for this version landed between 190-200 hp.

RB25DET-NEO

The turbocharged variant of the RB25DE-NEO modeled, managed a cool power output of about 270-280hp at peak power.

Used in: R32 Skyline, R33 Skyline, Early R34 Skyline, Nissan Stagea

RB26DETT

Used in the Nissan GT-R Skyline between 1989-2002 you could say the RB26 was the daddy of the RB-series. It was the first engine in the series to utilize twin turbos. And while the original engine due to a “gentlemen agreement” between Japanese automakers only produced a ‘mere’ 280hp in factory form – it is said that these engines came from the factory with about 340~hp. The RB26DETT is known to be able to withstand the power of around 600hp without even changing the factory internals, which made this a fantastic tuner engine.

Used in: Nissan Skyline GT-R R32, Nissan Skyline GT-R R33, Nissan Skyline GT-R R34, Nissan Stagea 260RS

RB30

The RB30 was one of the most uncommon variants and was almost exclusively sold to the Australian car market. Ironically, although being a Nissan-designed engine, the RB30 was more commonly known as the GM-Holden Engine as it was mostly used in the Holden VL Commodore, but the non-turbo version was also used by the R31 Skyline. All RB30’s used SOHC technology.

RB30E

This was the non-turbo version and was used in both the VL commodore and Nissan Skyline R31 GTS1/2. The RB30E produced 155 hp in the commodore while producing 175hp in the GTS1 and 190hp in the GTS2.

Used in: R31 Skyline, R31 Skyline GTS1, R31 Skyline GTS2, VL Commodore

RB30ET

The turbocharged variant of the RB30E produced around 201hp and 218lb-ft. Unlike the other engines on the list, this one was never actually put inside a Nissan. Holden had a contract with Nissan to supply the engines, and the contract said that they could not put it in any of their cars.

Used in: Holden VL Commodore

Conclusion

The RB-Engine Series was an amazing technological advancement made by Nissan. The engine was versatile and was not only used in sports cars but wagons and SUVs as well. In comparison to America’s large V8s the RB-engines, we’re light and nimble while still achieving a large power output. They were also smaller, as the displacements for American V8s could easily surpass 8-Litres, the most powerful RB had a displacement of 2.6-liters. This made it so that the RB could be fitted into smaller chassis, which allowed these cars to have lower weight and improved handling compared to their counterparts.

The RB series is loved by tuners since they came “very well built” from the factory. That means that tuners could double, and sometimes triple the factory horsepower without ever having to touch the engine’s factory internals.

If you’re interested in the predecessor to the RB I’ve got an article covering the Nissan L series engine!