Home FAQs FAQ – What is the RB26 JDM Engine?

FAQ – What is the RB26 JDM Engine?

October 15, 2014

Yet another chapter in the long history of Japanese super engines of the 1990s, the RB26DET is in many ways the turbocharged inline six ring that all import enthusiasts reach for. First found in the 1989 Nissan R32 Skyline, the RB26DET made a triumphant return in the R34 many years later. The RB26 is a little harder to source than the RB25 or RB20, as it was only found in the GT-R version of the R32.

The biggest and baddest of the RB family of engines, outside of the lesser known RB30, the RB26 JDM Engine is one of the best Japanese engines ever produced. Following the similar recipe of an iron cast block coupled with a lightweight aluminum cylinder head, the inline six RB26 JDM Engine comes with twin turbochargers and a motor that loves to rev.

With a 86mm bore and 73.7mm stroke the RB26DETT displaces 2568cc and carries a boost friendly compression ratio of 8.5:1. And thanks to that over-square design and superior cylinder head valvetrain, the RB26 can comfortably rev to 8300 RPM with little worry.

Differences between the RB25 and RB26 JDM Engine are many, as the RB26 took the time to address some of the issues that plagued it’s smaller cousin. The crankshaft and iron block were reinforced by way of iron rib bearings and block reinforcements. The crankcase was connected to a one piece ladder frame block, helping to lessen crankshaft movement and out of spec situations. Like the 2JZGTE and many other Japanese turbocharged engines, aluminum pistons and under piston oil squirters were employed to help keep the motor running.

The RB26DET DOHC cylinder head is where much of the magic occurs. A heavy dose of performance and cutting edge (for it’s time) technology was used to create a high revving turbocharged fire-breathing monster that’s called the RB26DET. The stock camshaft durations were 240° for intake and 236° exhaust, with 8.58mm and 8.28mm of lift. The valves are sodium filled for weight and heat transfer, something that’s normally reserved for race only engines.

Valve diameters are 34.5mm for intake and 30mm for exhaust, and the RB26 JDM Engine was the first in the RB family to move away from the hydraulic lifter design in favor of bucket-type followers to prevent valve-train failures at high engine speeds. This enables the RB26DET to rev like there’s no tomorrow, and a large reason why enthusiasts and engine swappers want the RB26DET instead.

The throttle body and induction system received a complete overhaul from the RB25DET, and individual throttle bodies are connected to the intake manifold and plenum. Direct coil on plug lights off the mixture and to maximize the combustion chamber’s efficiency and burn, the engine used a cross hatch intake pattern to increase atomization. The RB26DETT can be found in in every R32, R33 and R34 Nissan Skyline GT-R, and there’s only a handful of changes from that large year range.

In fact, the only difference between any of those generation RB26DETT’s would be the ball bearing T28 or Super 60 turbocharger found in the R34 Skyline GT-R which shares a lot features as the turbo found in the SR20DET. Previous models of the RB26DETT came with a standard 360 thrust bearing Garrett turbocharger.

Electronically boost limited to 10psi in stock form, the RB26DET is well known for producing more than 1000hp with the proper level of supporting mods and tuning.

Nissan’s tuning division, Nismo offered modified versions of the Skyline GT-R called the N1 and N2. With upgraded components, bigger turbos and stroked to 2.8 liters, these RB26DETT’s are some of the most awesome engines to ever leave the small island of Japan. Sadly, thee production of RB26 JDM Engine came to an end in 2002 when the R34 was decommissioned.