Some of the world’s most tunable engines originate from Japan. We’re going to show you which are best and what to do with them. 

It’s safe to say that in the tuning scene a lot of engines are more famous than the cars. In fact some cars are only famous thanks to their engines. But the reason for this is simple – the engines have huge tuning potential. In all honesty, most of the engines aren’t amazing performers when standard. But it’s the highly tuned ones that bring the fame, and this feature is all about these engines. And how to realise
their potential…

Best Japanese engines to tune

1. Nissan RB Series
The engine that gave the Nissan Skyline worldwide fame, the RB is a turbo straight six, fitted to R32 to R34 Skylines, as well as a few more unusual vehicles. The three main turbo versions, the RB20DET, the RB25DET, and the RB26DETT have long been known as tuners dreams.

The RB20 is the smallest capacity and lowest power engine of the bunch, at just two-litres and only 210bhp. But that doesn’t mean it’s the poor relation – far from it. Put a decent size turbo on it and things really come alive – 450bhp and 8,000rpm is possible on standard internals, and 600bhp-plus is achievable from a fully built engine. And they love to rev too; a big power RB20 revving its nuts off is an incredible sounding engine.

The RB25 is the most common of the RB lumps in the UK, found in countless R33 GTSTs and R34 GTTs, and as it’s a 2.5-litre turbo that makes an easy 300bhp with really minor tweaks, and a pretty safe 500bhp with a big turbo conversion even on standard internals. It’s no wonder it’s a popular engine to tune. Although some say the RB25 engine is almost as capable as the RB26 when fully built for mega power, most people tend to stick around the 500bhp mark, as that’s achievable relatively cheaply and if done right it has tons of torque and a great powerband.

The RB26DETT is the daddy of the RB engines, the one found only in R32-R34 GT-Rs, and an engine designed from the start for one reason only, and that was to win races. As the engine was designed for Group A Touring Car racing in the late ’80s, most of the standard parts, especially the head, crank, rods, manifolds and intercooler had to be awesome, because the race rules meant they weren’t allowed to be changed.

Because of this, these parts are rarely changed below about 650bhp, and some people have even hit the magic 1,000bhp figure on engines running standard internals. While half the world likes to claim their mate has a 1,000bhp Skyline, in reality that’s an expensive number to hit. But if you can afford it, that’s nowhere near the limit. What is the limit? Well, the Heat Treatments’ R32 GT-R from New Zealand is rumoured to be pushing out around 1,800bhp from its RB26!

Unusually though, there is another turbo RB, the RB30ET. This was an Aussie-only single cam turbo engine not even found in a Nissan, but in a Holden four-door saloon. Despite having 12 less valves and one less cam than the other versions, and pushing out less power than even the RB20DET as standard, with a bit of tuning it was soon realised even 1,000bhp was possible, and with massive torque thanks to having the three-litre engine.

The current favoured trick in RB tuning is using the RB26 cylinder head with the RB30 block, along with a mahoosive turbo, to give the huge power RB26s are capable of, but with big RB30 torque. Best of all, for this the RB30 block doesn’t need to come from a turbo version, and non-turbo RB30s can be found in all kinds of places, even old Nissan Patrol 4x4s in your local free ads.

1 2