We witnessed the RB engine’s evolution from its initial production up to its latest updates, engine development while continuing doing so in many departments. The RB20 and RB26 reflect the innovation that Nissan wants to explore. Moving on, we want to have a simple discussion on which is a better engine between these two, the initial or the one that is considered to be a revolutionary engine. Both are excellent engine and has the right to claim to be, but which is better?
Join me as we crack the unique characteristics of these two engines and let us compare their potentials, design, reliability, and many more.
Let’s get right to it!
The Nissan RB20 Engine:
- Production Run: 1984 – 2002
- Cylinder Head Material: Aluminum
- Cylinder Block Material: Cast-iron
- Configuration: Straight-six
- Bore: 78 mm
- Stroke: 69.7 mm
- Valvetrain: SOHC two valves per cylinder and DOHC four valves per cylinder
- Displacement: 2.0 L (1998 cc)
- Compression Ratio: 8.5
- Weight: 580 lbs.
- Maximum HP: 212 HP at 6,400 RPM
- Maximum Torque: 195 lb-ft at 3,200 RPM
The Nissan RB20 engines are the first machines fitted on the Nissan Fairlady 200ZR and the HR31 Skyline, produced in Mid-1985. It comes in two cam releases, with the early twin cam engines features the Nissan Induction Control System Injection system (NICS). In contrast, the succeeding twin cam engines used an Electronic Concentrated Control System (ECCS). Later models that used ECCS engine management obliterated the small twelve runners and replaced them with larger ones – but they retained twelve ports on the head, hence a splitter plate. It also powered the A31 Cefiros, C32, and C33 Laurel. The Fairlady 200ZR is installed with an inter-cooled RB20DET.
The engine was based on the framework of the L20A engine. It has a cast-iron cylinder block and aluminum cylinder heads. The cylinder bore diameter is 78 mm; piston stroke is 69.7 mm, and a compression rating of 8.5.
The RB20 engine has seven variations under its name. And the first engine to come out in an RB20 name is the RB20E used in the C32 Nissan Laurel, produced in late-1984. R32 Skylines, Laurels, and Cefiros used the 1989 – 1993 release as their engines with an improved head design, more commonly known as the ‘Silver Top’ engines.
The RB20 engine variations are comprised of the following:
RB20E is the first release and features a single cam that can produce up to 14 HP at 5,600 RPM and 133 lb-ft of torque at 4,400 RPM. A turbocharged version, RB20ET, was followed right after the release of RB20E, which is also a single-cam but has a higher power production at 168 HP at 6,00 RPM and 152 lb-ft of torque at 3,200 RPM.
Nissan produced a twin-cam RB20 called RB20DE to produce 153 HP at 6,400 RPM and 137 lb-ft of torque at 5,600 RPM. A turbocharged version, RB20DET, of the same variant was also made that has a maximum power production of 212 HP at 6,400 RPM and 195 lb-ft of torque at 3,200 RPM. It also has a variant named RB20DET-R with a peak power of 207 HP at 6,400 RPM and 181 lb-ft of torque at 4,800 RPM.
A 12-valve, single-cam, autogas LPG powered engine badged as RB20P was rated at 93 HP at 5,600 RPM and 105 lb-ft of torque at 2,400 RPM. And lastly, a twin-cam NEO variant was made for a lesser emission and can produce 153 HP.
The Nissan RB26 Engine
- Production Run: 1989 – 2002
- Cylinder Head Material: Aluminum
- Cylinder Block Material: Cast-iron
- Configuration: Inline-6
- Bore: 86 mm
- Stroke: 73.7 mm
- Valvetrain: DOHC four valves per cylinder
- Displacement: 2.6 L (2498 cc)
- Compression Ratio: 8.5
- Weight: 570 lbs.
- Maximum HP: 316 HP at 6,800 RPM
- Maximum Torque: 289 lb-ft at 4,400 RPM
The Nissan RB26, more technically known as the RB26DETT engine or the twin-turbo RB26, is also a six-inline, 2.6 Liter that powered one of the most notable vehicles of our generation, the 1989 – 2002 Nissan Skyline GT-R models.
The RB26DETT cylinder block, identical to the RB20, is made from cast iron but without oil ports. It has a 86 mm cylinder bore, 73.7 mm piston stroke, and an 8.5 compression rating. The redesigned pistons installed were 1 mm lower and it is equipped with an RB25DET NEO connecting rods to join them. The engine’s cylinder block is covered with a 24-valve DOHC aluminum-alloy head with four valves per cylinder -two for both intake and exhaust and has no Nissan variable valve system VCT.
The primary advantage and we want to point out that the RB26DETT engine, instead of having a single flow of throttle, has six individual throttle bodies that measure 45 mm in diameter; and these three sets are arranged in a siamesed form. However, this kind of intake system varies from other RB engines since they use single ones.
The RB26DETT, in stock form, is already installed with a powerful parallel-twin turbo system. The engine sends the air into the intake manifold that uses a pair of ceramic Garrett M24 set by the wastegates to limit the maximal boost pressure to 10 psi. To add to that, the Skyline GT-R has a built-in boost restrictor to restrict to keep the boost under the critical level of 13 psi.
The earliest production of the RB26 engines was initially rated at 280 HP at 6,800 RPM and a 260 lb-ft of torque at 4,400 RPM. However, on the tail end of its production years, the numbers soared, nearly reaching the higher end 320 HP mark landing at 316 HP at 6,800 RPM and larger torque production of 289 lb-ft at 4,400 RPM. Mainly due to the development and modifications made to the engine.
Unfortunately, Japanese-made vehicle cars were limited to just 276 HP due to the Gentleman’s agreement signed by Nissan, which mentioned that they could not go beyond the number mentioned above. Though it appears to be lesser in the paper, many enthusiasts believed that the numbers penned on those papers were far from the true potential of the RB26 engine and stirs some phantom ratings. The twin-turbo RB26DETT machines can be found on exclusives such as the Skyline GT-R 32 and Skyline GT-R R33.
Nissan later modified the RB26 aesthetically and some ECU fine tunings. So in the Nissan R34, they used ball-bearing Garrett M24 T28 turbochargers separating from the typical journal-bearing turbos. Nissan also added fair amounts of upgrades such as a revised coolant/heater pipe diameter on the intake side of the block, stainless dump pipes; Igniter built into coil packs; the lighter casting of the intake manifold, and dual-mass flywheel.
The engine potential of the RB20 engine is not so close, especially when we are talking about how strong the stock internals are. The RB20 engine internals is good for about 400 HP, while the RB26, a larger one, can reach 600 HP in stock too. RB20 engines have a lower fuel supply at 270 cc/min, and the RB26 almost doubled the number at 440 cc/min. If you want to go beyond what is rated from the factory, you need the engine to be built again and customize the parts that need to be upgraded so these engines can reach higher power outputs.
You cannot go wrong on both, though. However, we cannot deny that RB26 has a better block and internals since it can withstand such numbers that RB20 cannot hold its own if not for changing its components.
For the torque production, RB20 is also inferior to the RB26, mainly because the RB20s lack some torque below 4,500 RPM ranges, affecting the engine’s abilities. It is a good balance that RB20s can rev up to 8,000 RPM with the stock valve train, but that does compensate for its torque shortcomings.
Furthermore, it is not hard to find aftermarket items for these engines, such as turbochargers, camshafts, intercoolers, head gaskets, and many more.
Problems Surrounding the Engines:
RB engines are known as one of the most reliable and durable engines Nissan produced especially considering that these two engines are performance-based and more of a sporty profile. These engines can definitely last a lifetime with high-quality engine oil and regular maintenance. However, there are some issues in the RB26 engine regarding faulty oil pumps and its excessive oil consumption; well, oil pumps might be the cause. There are also reports that the fuel ignition coils malfunction over time.
Meanwhile, the RB20 engine is not safe either because it also has issues regarding its oil system as well as ignition coils that cause an engine misfire. Almost similar to the RB26.
The twin-turbo RB26 and the low-profile but aggressive RB20 engines are not as same as they are. The RB26 is more power-oriented, has a higher torque production, larger fuel supply, and can put up colossal production numbers due to its strong internals, making it more ideal as a tuning platform and swapping. The thing with the RB26 engine is their price; they are more expensive than the RB20s, even RB25s. But it really gives a bang for your buck.
However, if you have a tighter budget and want to start a project car immediately, you can opt to have RB20. Cheaper, has decent power enough to drive and drift, and also considering its availability. It may not be as good as RB26, but RB20s are better than its competitors in that category.
The RB26 engines also revolutionized the way machines are made today; it is far more sophisticated than the advanced RB25, so it is easy to say that RB26s are better due to your money’s worth and the upgrades that attached to it.
Still, we should put some respect on RB20’s name since it pioneered and paved the way for the RB engines to be introduced in the automotive world. Though it lacks most of the technologies that the RB26 have, sure enough, that succeeding RB engines -including RB26, are modeled right next to the RB20 engine.