Saab 9-5 NG V6 TiD⁶: The Last Remaining V6 Diesel Prototype!

Introduction: A One-of-a-Kind Saab 9-5 NG V6 Diesel

In the world of automotive enthusiasts, few brands inspire the kind of loyalty and passion that Saab does. Known for their innovative design and unconventional approach, Saab has a dedicated following despite the brand’s unfortunate demise in 2011.

However, within this dedicated community, there are stories of rare and unique Saab models that continue to captivate enthusiasts. One such story is that of the Saab 9-5 NG V6 Diesel, a vehicle that remains largely unknown even to the most die-hard Saab fans. This is the story of a forgotten powerhouse, brought back to life by a Swedish enthusiast, Ola Persson, and the rare V6 Diesel engine that powers it.

The Origin of the V6 Diesel: Project RA 629 DOHC

The story of the Saab 9-5 NG V6 Diesel begins with the ambitious RA 629 DOHC project (A29DT), a General Motors (GM) Europe initiative that aimed to create a premium V6 diesel engine for high-performance cars. The development of this engine was a collaborative effort between VM Motori in Italy (handling both hardware and software), Rüsselsheim, Germany, and Detroit, USA (overseeing car integration), with the overall project management based in Trollhättan, Sweden, Saab’s home.

The engine’s development officially started in 2006 after a feasibility study conducted by VM Motori. It was designed to be a powerful and reliable diesel engine, built to meet the growing demand for premium diesel cars. With its 2.9-liter capacity, the engine was capable of producing 250 horsepower and 550 Nm of torque, numbers that made it a formidable contender in the luxury diesel market. However, despite its potential, the project faced a tragic end due to the financial troubles that plagued GM and Saab.

The Saab 9-5 NG: A New Era Cut Short

The Saab 9-5 NG was supposed to usher in a new era for the Swedish automaker. With its sleek design and modern features, it was poised to compete with luxury sedans from brands like BMW and Mercedes-Benz. The V6 Diesel was to be one of the engine options that would elevate the 9-5 NG to the next level. However, the financial crisis that struck GM in 2008 led to the cancellation of the RA 629 project. By December of that year, GM issued a directive to destroy all prototypes and test cars equipped with this engine. Most of the cars were either scrapped on-site or sent to Rüsselsheim for dismantling.

Miraculously, one prototype Saab 9-5 NG V6 Diesel survived. For reasons unknown, it was left forgotten in a corner of a facility, a symbol of what could have been. This car, however, would eventually be rediscovered and brought back to life by Ola Persson, a man with a passion for restoring and preserving rare Saab models.

Ola Persson: A Saab Enthusiast with a Vision

Ola Persson is no ordinary Saab enthusiast. With a collection that includes a variety of Saab models, each one meticulously maintained, Persson is known for his dedication to the brand. But what truly sets him apart is his passion for taking on complex restoration projects. His self-built Saab 9-5 SportCombi, which could easily have passed as a factory prototype, is just one example of his work. However, his most ambitious project to date is the restoration of the forgotten Saab 9-5 NG V6 Diesel.

Persson’s love for Saab and his dedication to preserving its legacy are evident in the painstaking efforts he put into this unique V6 Diesel model. At the Saab Festival in Trollhättan in 2022, Persson showcased this remarkable vehicle, which had been fully restored and registered for use on public roads. The journey to bring this car back to life was not an easy one, but for Persson, it was a labor of love.

The Unique V6 Diesel Engine: A Rare Powertrain

The RA 629 DOHC engine was a marvel of engineering. With its V6 configuration, 60-degree bank angle, and common-rail injection, it was designed for high performance and durability. The engine featured a turbocharger with variable geometry, which allowed it to deliver power smoothly across the rev range. In its final form, the engine produced 250 horsepower and a massive 550 Nm of torque, making it one of the most powerful diesel engines ever developed for Saab.

The development process included several key stages:

• The Beta 1 phase, focused on component functionality, was completed by the end of 2006.
• By the spring of 2007, the Beta 2 phase was underway, testing the durability of the engine components.
• The Gamma phase, which ensured complete engine durability and off-tool status, was achieved by late 2007.

By December 2008, the engine was fully developed and ready for production. Pre-production was scheduled to begin in January 2009, but the project was halted during Christmas of 2008 due to GM’s financial troubles, leading to the cancellation of the entire program.

One of the remaining Saab 9-5 NG models, equipped with this engine, is most likely from the Gamma phase of development. This means it was built using tools intended for serial production, but it might not have undergone the full serial production process. The engine had already passed all durability tests, with calibration around 65-80% complete. While emissions were within acceptable limits and potential engine failure conditions were accounted for, the engine still lacked calibration for extreme conditions like high altitudes and extreme temperatures. Furthermore, driveability calibration, particularly in its integration with the gearbox, was incomplete. This resulted in hard shifts and slower-than-expected transitions.

While this engine never made it into mass production for Saab, it did find a second life in several premium models from the GM-Fiat collaboration. Vehicles like the Jeep Grand Cherokee, Chrysler 300, Maserati Ghibli, and Dodge Ram all benefited from the technology that had originally been developed for Saab. However, the engine was modified to a 3.0-liter displacement for these applications, making the 2.9-liter version in the Saab 9-5 NG V6 Diesel truly unique.

The Restoration: A New Life for the Saab 9-5 NG V6 Diesel

When Persson first acquired the Saab 9-5 NG V6 Diesel, it was in rough shape. Years of neglect had taken their toll on the car, and many parts were missing or damaged. However, Persson saw the potential in this rare vehicle and began the restoration process. One of the first challenges was getting the car roadworthy again. The air conditioning system, for example, had been rumored to be missing, but Persson discovered that it was simply empty of refrigerant. Once refilled, the system worked perfectly.

The bigger challenge was registering the car for road use. Since all prototype vehicles had been deregistered following Saab’s bankruptcy, it was no small feat to get the necessary paperwork in order. With the help of contacts in the Saab community and the original documentation from the car’s time as a prototype, Persson was eventually able to get the car legally registered in Sweden.

Performance and Upgrades: A Modern Saab with Classic Power

Persson didn’t just restore the Saab 9-5 NG V6 Diesel to its original condition; he improved upon it. In keeping with Saab’s performance heritage, Persson upgraded the car with several key enhancements. He added the Aero package, which included sportier bumpers and visible exhaust tips. A Hirsch Performance spoiler kit was also installed, along with an upgraded brake system featuring 4-piston calipers and high-performance rotors.

To complete the look, Persson fitted the car with 20-inch Turbo-star wheels, a nod to Saab’s legacy of combining performance with design. The result is a car that not only performs exceptionally but also looks the part of a high-performance Saab. The upgraded exhaust system provides a deeper, more aggressive sound, perfectly complementing the power of the V6 Diesel engine.

A Saab Legacy Preserved

The Saab 9-5 NG V6 Diesel is more than just a rare car; it’s a symbol of what could have been for the Saab brand. Thanks to the efforts of Ola Persson, this forgotten powerhouse has been restored to its former glory, complete with the unique V6 Diesel engine that was once destined to power Saab’s premium models. While the RA 629 DOHC project may have been cut short, its legacy lives on in this one-of-a-kind vehicle.

For Saab enthusiasts, the story of the 9-5 NG V6 Diesel is a reminder of the brand’s innovative spirit and the passion of those who continue to preserve its legacy. As Persson’s restoration shows, even in the face of adversity, the Saab community remains dedicated to keeping the brand’s history alive.