The RB26 is part of Nissan’s RB engine family, which includes other legendary engines such as the RB20, RB25, and RB30. Most enthusiasts consider the RB26DETT to be one of the best engines in the RB family. GTRs first represented Nissan’s 2.6 Liter twin-turbocharged Japanese craze RB26DETT engine in 1989.
Nissan used the RB26 in the Skyline GT-R, including the R32, R33, and R34 generations.
Nevertheless, it is a highly-respected engine in the industry with its high power above its weight. This created a cult that even owners of different cars such as 300ZX, 350Z, Infiniti G35, Ford Mustang, and many more follow.
Nissan halted production in 2004 as they moved to newer and more efficient engine platforms. Luckily, after 13 years of indefinite leave, through Nismo’s announcement, Nissan started RB26 engine production again in 2019 for aftermarket support.
It began in 2017 with just some parts like exhaust systems, intake, etc., but they agreed to produce more of this engine due to its growing demand.
So, with that, let us talk about the RB26 engine’s power, engine design, applications, issues, upgrades, and potential. We’ll also cover its contribution to the automobile field and how it became so popular with tuners.
Nissan RB26: Engine Specifications and Design:
- Production Run: 1989 – 2002
- Cylinder Block Material: Cast-Iron
- Cylinder Head Material: Aluminum Alloy
- Configuration: Inline-6
- Bore: 86 mm
- Stroke: 73.7 mm
- Valvetrain: DOHC 4 valves per cylinder
- Displacement: 2.6 L
- Compression Ratio: 8.5
- Weight: 570 lbs.
- Max HP: 316 HP at 6,800 RPM
- Max Torque: 289 lb-ft at 4,400 RPM
For this article, we’re mostly going to look at the RB26DETT, however, it is worth noting that Nissan produced a naturally aspirated RB26 known as the RB26DE. The RB26DETT was Nissan’s ultimately performance package. Nissan designed this engine for use in the Skyline GTR, which was its most performance oriented vehicle for sale. Starting from the top and moving down, let’s take a look at the cylinder head first!
Early production of 2.6 L RB26DETT produced was rated 280 HP at 6,800 RPM and 260 lb-ft torque at 4,400 RPM. However, on its production end, the power output was increased and reached 316 HP at 6,800RPM and 289 lb-ft of torque at 4,400 RPM.
This became possible due to the modifications and engine development and “the gentlemen’s agreement” made by Nissan in which Japanese cars should not exceed 276 HP. Though it appears to be less than 280HP on paper, most enthusiasts agree Nissan underrated the engine. Most dyno testing proves the RB26 produces approximately 316 HP coming straight from the factory.
RB26 is internationally recognized and famous for its power and unlimited power potential due to its construction, especially the iron block and forged internals. As a result, it makes it one of the most chosen platforms for tuners and aftermarket modifications in general.
You can find such engines on Skyline GT-R 32 and Skyline GT-R R33.
Nissan RB26: Cylinder Head
The cylinder head on the RB26 is constructed from cast aluminum to save weight and improve thermal efficiency. It features two camshafts (DOHC) and four valves per cylinder. The exhaust valves are sodium filled for thermal efficiency. The intake valves are 34.5 mm in diameter, and the exhaust valves are 30 mm.
Interestingly enough, Nissan didn’t add variable valve lift or variable valve timing to the RB26. However, you can fix the lack of VVT and VVL with HKS’ “V CAM” system. The camshafts are driven by a timing belt as you’d expect.
The intake system of the RB26DETT uses six individual throttle bodies instead of a single throttle body; each throttle body is measuring 45 mm in diameter, and the three sets of two throttle assemblies are tied together. This kind of intake varies from other RB-series engines as other models use a single throttle body.
This type of intake system offer better performance and significantly improved throttle response compared to the standard type of intake system, but it also increases complexity and it more prone to failure.
RB26 engine uses a parallel twin-turbo system. The air goes into the intake manifold using a pair of ceramic Garrett M24 turbochargers set by the wastegates to limit maximum boost pressure to 10 psi. However, Skyline GT-R has a built-in boost restrictor to keep the boost under the critical level at 13 psi.
With a parallel twin-turbo system, the turbos are sized equally and work together to give the RB26 more power. In other types of twin-turbo systems, a smaller turbocharger spools up first to provide low-end power until the larger turbo spools up to make top-end power.
It is worth noting the R34 received differentf ball-bearing Garrett M24 T28 turbochargers contrary to journal bearing turbos found on earlier RB26 engines, and those turbos continued to use ceramic exhaust turbine wheel.
- Solid Lifter valve actuation, shim under bucket
- 6 Throttle Body Intake
- Belt-Driven Cams
- Water-cooled, oil pressure lubed turbos
- Crank Angle Sensor driven off exhaust cam tells the ECU of the crank and cam position
- Sodium filled exhaust valves
Nissan RB26: Bottom End
The RB26DETT engine block, in contrast to RB25DET, is made from cast iron without an oil port. While Nissan could’ve opted to use cast-aluminum for the block, they ultimately used cast-iron because it’s cheaper and stronger, but it’s also much heavier.
The deck of the block is semi-open, which is a great middle ground between a closed deck and an open deck. A closed deck provides the most cylinder stability and strength, while an open deck provides less stability but much better cooling. With a semi-open deck, you get the best of both.
The forged steel crankshaft in the RB26 features a 73.7 mm stroke redesigned pistons that are 1 mm lower; also installed are RB25DET NEO connecting rods and a compression ratio of 8.5.
One of the most important features to keeping any high-performance engine cool is the use of piston oil squirters. This spray oil on the bottom side of the pistons to help keep them cool, which is especially important in scenarios such as a race track, where the engine is under high load for an extended period of time.
The forged I-beam connecting rods are very strong are capable of withstanding a MASSIVE amount of power. They really only need to be replaced in extremely high-power builds where the extra strength is needed.
- OEM cast pistons have cooling channels under crowns (extra oil cooling to regulate piston temperatures)
- Piston Oil Squirters
- 8 Counter-weighted crankshaft
- I beam connecting rods
R34 GT-R RB26 vs R32-R33 RB26:
- Dual Mass Flywheel
- Plastic CAM Gear Cover
- Different Coil Cover Emblem
- Candy Red Coil Pack Covers
- Lighter Casting Inlet Plenum
- Hitachi Crank Angle Sensor
- Igniter Built Into Coil Packs
- Stainless Steel Dump Pipes
- Ball Bearing Turbo with Ceramic Exhaust Turbine Wheels
- 3:55 Sump Ratio
- Revised coolant/heater pipe diameter on the intake side of the block
RB26DETT N1 2.6 L
The original plan for the R32 GT-R is to have a 2.4 L displacement instead of 2.6 L and be loaded with the RB24DETT engine, which was developed by Nismo (Nissan Motorsports) for groups A and N motorsport.
However, Nissan found out that these engines require too much effort to maintain in such competition. So, they introduced the sport version RB26DETT N1 block.
This engine features an upgrade in the camshaft, reinforced connecting rods and pistons, improved water and oil channels within the block, a higher crankshaft specification, the use of Garrett M24 ball-bearing T25 turbochargers, and an upgraded turbo manifold.
The most significant difference between the turbochargers in the N1 and the standard RB26DETT engine is their turbine wheels. The former uses ceramic instead of steel.
Unfortunately, ceramic turbine wheels are quite unreliable to the nature of their characteristics, especially when used at high rotational speeds, centrifugal forces included.
Nismo RB26DETT N1 has a bore of 86 mm and can be bored up to 88 mm; its block is cast with an identification mark of 24U, which the standard RB26DETT is marked with 05U. N1s are compatible with all GT-R engine bays.
There is another engine that is called RB26DETT Z2, which is used in the Nissan Skyline GT-R-Z-Tune, which Nismo also builds. It has a more robust GT500 engine block and produces 495 HP and 400 lb-ft of torque.
And in 2001, RB26DETT N1 was replaced with a purely sporty VQ30DETT engine, followed by VR38DETT in 2007, which can be found in Nissan GTR R35.
Nissan RB26: Engine Tuning, Upgrades, and Modification
Increasing your RB26 is easy, for there are lots of aftermarket upgrades available to choose from. Popular modifications include a Nissan N1 oil pump, oil coolers, N1 water pump, and fuel pressure regulator.
You will also need a Bosch 044 fuel pump, fuel rail, 550 cc/min fuel injectors, boost controller, 3-layer radiator, Apexi power intake, as well as APexi Power FC and a 3-inch performance exhaust.
Install all of these upgrades and tune the ECU. This can give you 330 HP and a 15 psi pressure boost.
But if you wish to add more and reach 400 HP, you need to replace your OEM turbochargers with the GTR RB26DETT N1 turbochargers, buy a big intercooler and an MLS gasket head.
You will gain at least 400 HP and a boost pressure increase to 17 psi.
The next step is to push it to 550 HP. Here it would be best to buy ACL bearings, HKS GT2530 turbochargers, cam gears, Z32 MAF, NGK 10 spark plugs, 750 cc/min fuel injectors, split fire ignition coils, blow-off valve, HKS timing belt, and a 3.5-inch performance exhaust system.
It is good that RB26DETT has excellent stock internals for they can withstand high power output that can reach 650 HP.
But some owners really want to push a 900 HP run, yes it’s possible, but it’s not a good idea. Go buy some forged pistons, H-beam rods, enlarged oil pan, ATI crank dampers, ARP head studs, huge valve with springs, performance intake manifold, HKS 3037 turbochargers, 1000 cc/min fuel injectors, and do some head porting.
Nissan RB26: Common Problems
Even though RB26s are sport and performance-centric kind of engine, is it reliable and durable as it can prove that their internals can withstand such power output.
However, prior to its reign, R32 RB26 engines before 1992 had an oiling problem where the crankshaft that meets the oil pump was designed too small, leading to the oil pump failure at a high RPM range.
Nissan was able to solve this problem by equipping a wider oil pump drive and water pump.
There are aftermarket performance parts makers who also make this kind of product like extension drive collars to alleviate the problem. An aftermarket company developed a spline drive solution, which is, by design, is contrary to the traditional flat drive system and uses splines to drive the oil pump gears.
This kit is available for most of the RB26 engines, including N1s and Nismos.
There are also reports of oil starvation issus in the early RB26DETT, which can be found in the Nissan Skyline GT-R R32. This commonly happens during cornerings and hard turns.
To add to that, you need to use high-quality engine oil; and change the engine’s timing belt every 60,000 miles to prevent breakage.
Summary
Nissan RB26 engines have already made a name for themselves on different platforms and even on international stages. When it passes by, it is iconic, legendary, and an “uh-ah” machine.
It has been popular on street performance, car shows, motorsport, and even hobbyist alike, for they are that good to get your hands on. Its power, handling, cornering, and deep run for potential are unparalleled compared to the engine in its time.
It holds unique pigeon holes in our hearts and will always be. Just take care of it and always conduct a periodic engine oil change, usage of high-quality gasoline, and overall maintenance; it can last a lifetime for they are highly reliable and durable.
I hope that you understand the RB26 engines more with this little guide. As you go deeper into the wonder of the Nissan Skyline GTRs, may this help you navigate through the things that RB26 engines have.