There’s nothing quite like unlocking the true potential of a single-turbo RB NEO engine—and this RB25DETT is a perfect example. Tuned by Steve @ Motorworx and running a Haltech Elite ECU, this beast can now put down a solid 400+ horsepower on high boost and 370 on low bost, and it’s as responsive as it is raw with its unique Tomei Turbo OEM bolt on in its low mount position.

The Setup

The RB25DETT is often overshadowed by its bigger brother, the RB26, but with the right setup, it’s a seriously capable platform. This engine came in clean and ready, but we knew there was more to be had with the right brain behind it—enter Haltech.

We opted for full Haltech engine management to take control of fueling, ignition, and boost. The ECU offered the flexibility and reliability needed to extract maximum performance while ensuring safety across all operating conditions.

The Tuning Process

The car rolled into the dyno at Motorworx, where we began by setting a solid base map. From there, we fine-tuned fuel delivery, adjusted timing for peak efficiency, and refined boost control to balance power and drivability.

Throughout the session, we closely monitored multiple channels live whilst tuning namely:

• Fuel pressure

• Boost pressure

• AFR (Air-Fuel Ratio)

• Oil pressure & temperature

Thanks to the Haltech ECU’s data-logging and real-time adjustment capabilities, we were able to find that sweet spot—where performance meets reliability.

The Result? A Clean 400HP +

There’s something satisfying about hitting a round number like 400hp, but this wasn’t about chasing a number—it was about smooth delivery, strong midrange torque, and a healthy safety buffer which heaps more room for scope.

The power delivery is linear and confident, with the Tomei Single turbos spooling quickly and holding boost strong all the way through the rev range. Whether it’s for spirited driving or weekend pulls, this R34 NEO RB25DETT is ready.

Final Thoughts

Over the nearly 3 decades it’s always a pleasure tuning RBs, but this one stood out for how well it responded to changes. Even with the original Nissan ECU with its FCTuningNistune ECU Solution, which got things initially going. Now with Haltech providing the brains, and Motorworx providing the tools and environment to get the job done, the result is a well-balanced 400hp street car with tons of personality.

Got a project in mind or want to wake up your own RB? Get in touch.

The post TUNING THE NISSAN RB25DETT (R34GTT) first appeared on FC TUNING.

The post TUNING THE NISSAN RB25DET (R34GTT) first appeared on FC TUNING.

Steve had worked with the car from close to its original specification and previously calibrated it using FC Tuning’s Nistune solution. When Haltech released the Platinum Pro Plug-In for the R34 GTT, the car offered the right opportunity to move to a more capable standalone engine-management platform without unnecessarily disturbing the factory wiring loom.

At the time, this was the first Nissan Skyline R34 GTT in the UK to receive a Haltech Platinum Pro Plug-In ECU. The top-mounted BorgWarner EFR 7670 installation was also among the first applications of this turbo on an RB-series engine in the UK.

Customer objective and original configuration

The customer wanted to retain the standard RB25DET NEO engine internals for the initial stage, while creating a hardware and engine-management foundation that could later support a forged bottom end and a worked cylinder head.

The 2014 specification retained the internally stock RB25DET NEO and included:

• Haltech Platinum Pro Plug-In ECU
• internally gated BorgWarner EFR 7670 turbocharger
• custom top-mount exhaust manifold
• R35 GT-R injectors, fitted as direct drop-in replacements for the OEM RB25DET NEO injectors
• upgraded fuel system
• upgraded exhaust
• performance air filter and supporting intake modifications

The planned forged-engine and cylinder-head phase remained an option rather than completed work. The stock-engine combination drove so well that the customer never proceeded with it. As of 2026, the engine still had not needed the proposed forged and head-worked upgrade.

Why use the Haltech Platinum Pro Plug-In?

The Haltech platform provided a more advanced engine-management foundation for the BorgWarner EFR 7670 and supporting hardware. The Platinum Pro Plug-In could integrate with the R34 GTT without replacing or heavily modifying the original engine wiring loom, preserving the integrity of the car while providing the additional control required for the new turbo and fuel-system specification.

For a road-focused car, this was a better fit than carrying out a more invasive universal standalone ECU and custom-loom conversion.

Supplied, installed and calibrated by FC Tuning

Steve supplied and installed the Haltech Platinum Pro Plug-In ECU before calibrating the car on a Dyno Dynamics dyno using 99 RON pump fuel. The setup was refined to provide strong usable performance while retaining the stock engine internals and OEM-like road manners.

Engine safety and control strategy

The calibration used Haltech’s fail-safe functionality together with a Haltech wideband control unit. The ECU monitored coolant temperature, oil temperature and intake-air temperature. The protection strategy also included oil-pressure monitoring and protection, overboost protection, air-intake strategies and boost-by-gear control.

The wideband controller supplied air–fuel-ratio feedback, adding another layer of protection and control for the internally stock RB25DET NEO.

Vehicle specification and result

• Vehicle: Nissan Skyline R34 GTT
• Engine: internally stock RB25DET NEO
• ECU: Haltech Platinum Pro Plug-In
• Turbo: internally gated BorgWarner EFR 7670
• Injectors: R35 GT-R direct-fit replacements
• Fuel: 99 RON pump fuel
• Boost: 1.5 bar
• Dyno: Dyno Dynamics
• Measured flywheel output: 534 hp and 501 lb-ft of torque

More power without sacrificing road manners

Despite the substantial increase in power, the owner reported improved fuel economy. Off boost, the car retained OEM-like drivability—if not better—while also gaining sharper throttle response. In the owner’s experience, it delivered the best of both worlds: considerably more performance without sacrificing everyday road manners.

The fact that the planned forged and head-worked phase had still not been required in 2026 provides a meaningful long-term outcome, rather than only a result from the original dyno session.

Watch the R34 GTT dyno video

The video above records the car and shows the final 534 hp and 501 lb-ft flywheel result at the end.

Dyno graph

Planning a Haltech-powered Nissan Skyline?

FC Tuning is an authorised UK Haltech dealer and can advise on ECU selection, supply, installation, setup and professional calibration for Nissan Skyline and other performance-engine applications.

Contact FC Tuning about your Haltech project, or learn more about Haltech ECU supply, installation and tuning.

The post Nissan Skyline R34 GTT RB25DET NEO – Haltech Platinum Pro Plug-In first appeared on FC TUNING.

Still on the stock turbo for now as it’s a daily runner but maybe a little more power in the future.

The post TUNING THE NISSAN RB25DET (R34) first appeared on FC TUNING.

Future mods to include an even bigger turbo capable of 600 + hp which will really turn this nice winged GTST into a fast road weapon.

More to come so watch this space.

If you like your Nissan Skylines remember to hit that LIKE button below and Share to a friend.

The post TUNING THE NISSAN RB25DET (R33) first appeared on FC TUNING.

Engine still in OEM form, just the usual RB bolt ons, but the owner will be looking forge the engine for long term reliability.

The stock RB25DET OEM ECU has been binned in favour for something different from the norm. A Megasquirt ECU system is now keeping things in check.
Great power from a well looked after factory Nissan RB25DET with PLENTY of potential once the engine is forged and then the boost on the Holset HX40 can be really wound up.

The post TUNING THE NISSAN RB25DET (R33) first appeared on FC TUNING.

Blown gaskets here and there were naturally hindering the engines power but once sorted, serviced,the ecu reset and retuned this nice RB powered showcar was soon back up and running nice with plenty of poke.

Still a lot more to come but after the initial hassles in putting yet another skyline right, I knew the owner would be happy with the power, so forget chasing numbers. It makes what it makes, as I like to state.

Enjoy the video and remember to hit that LIKE button and feel free to SHARE your to your petrol heads friends.

The post TUNING THE NISSAN RB25DET (R33) first appeared on FC TUNING.

Nice to things simple on these OEM New engine setups, with just bolt ons. In this case a hybrid turbo and Apexi programmable ecu were down for some mild tuning. Issues with an actuator on the day prevented us from laying down some decent power, but it still a nice result and a good base to work from for a remap next session in the near future.

The turbo has plenty of potential and I can see from experience the this engine will make alot more hp and a huge increase in mid range torque improving the fun and drivability, which is what we all need.

Everything kept in check with an old Skool plug n play Apexi PowerFC ECU.

Looking forward to catching up Al and giving you well over 400 ft Ibs of torque to match.

Remember to hit that LIKE button below.

The post TUNING THE NISSAN RB25DET (R34) first appeared on FC TUNING.

Next stop 400hp+ – Big turbo or Bolt on Hybrid, Injectors, MAF and a stronger clutch.

The post TUNING THE NISSAN RB25DET (R33) first appeared on FC TUNING.

One of m favourite colours, Nissan’s Bayside Blue

Featuring launch control for some fast road action.

More upgrade to come in the form of our custom top mounted Borg Warner turbo kits.

The post TUNING THE NISSAN RB25DET NEO (GTT) first appeared on FC TUNING.

Fitting all those mods though is a worthless act unless the engine management knows about it.

Nissan Skyline R34 GTT featuring an FCTuningNistune ECU Solution and launch control to compliment all the modifications fitted so everything is balanced.

The post Tuning the Nissan RB25DET (R34GTT) first appeared on FC TUNING.

FCTuningNistune ECU upgrade was fitted to allow full tuning of the engine with the mild boost pressure on the RB25DET.

A nice drive

The post TUNING THE NISSAN RB25DET (R34GTT) first appeared on FC TUNING.