For decades, Cadillac was synonymous with luxury, but in the early 2000s, the brand embarked on a bold new mission—to challenge the world’s best high-performance sedans. The result was the Cadillac CTS-V, a sports sedan that combined Corvette-derived V-8 power with sharp handling, aggressive styling, and a six-speed manual transmission.
When it debuted in 2004, the CTS-V made an immediate impact, signaling Cadillac’s intent to compete with European performance giants like BMW’s M Series and Mercedes-Benz’s AMG lineup. However, Cadillac didn’t stop there. Following the success of the CTS-V, the brand introduced two more V-Series vehicles:
- The XLR-V roadster (2006-2009)
- The STS-V sedan (2006-2009)
While these models never gained the same recognition as the CTS-V, they represented Cadillac’s commitment to high-performance engineering. What set them apart was their supercharged 4.4L Northstar V-8, an exclusive hand-built engine that blended raw power with refined performance.
This article takes a deep dive into the CTS-V, XLR-V, and STS-V, exploring their unique characteristics, engineering breakthroughs, and lasting impact on Cadillac’s performance legacy.
The Difference Between the CTS-V and the XLR-V/STS-V
The first-generation CTS-V (2004-2007) was powered by a Corvette-derived LS6 V-8, producing 400 horsepower and paired with a Tremec six-speed manual transmission. It was a rear-wheel-drive (RWD) beast, built to take on the best sports sedans in the world.
In contrast, the XLR-V and STS-V took a different approach, utilizing a unique, Cadillac-developed supercharged 4.4L Northstar V-8. Unlike the LS engines in the CTS-V, these Northstar engines were:
✔ Custom-built and hand-assembled at the GM Performance Build Center in Michigan.
✔ Designed exclusively for Cadillac’s rear-wheel-drive performance models.
✔ Equipped with a supercharger for instant torque delivery and high-speed capability.
While the CTS-V focused on aggressive track-ready performance, the XLR-V and STS-V emphasized high-speed touring with effortless power and refined engineering.
Performance Specifications of the STS-V and XLR-V
The STS-V and XLR-V were powered by the same 4.4-liter supercharged Northstar V-8, but their performance figures varied slightly.
Cadillac STS-V (2006-2009)
- Horsepower: 469 hp @ 6,400 rpm
- Torque: 439 lb-ft @ 3,800 rpm
- Transmission: Hydra-Matic 6L80 6-speed automatic
- 0-60 mph: 4.8 seconds
Cadillac XLR-V (2006-2009)
- Horsepower: 443 hp @ 6,400 rpm
- Torque: 414 lb-ft @ 3,900 rpm
- Transmission: Hydra-Matic 6L80 6-speed automatic
- 0-60 mph: 4.6 seconds
The XLR-V had slightly less power due to intake and exhaust system modifications required to fit the engine into the compact roadster body. However, both models delivered 90% of their peak torque between 2,200 and 6,000 rpm, ensuring instantaneous acceleration and smooth power delivery.
Engineering Innovations in the 4.4L Supercharged Northstar V-8
The 4.4L Northstar V-8 was an evolution of Cadillac’s legendary 4.6L Northstar, re-engineered specifically for high-performance applications. Key improvements included:
1. Strengthened Engine Block for Forced Induction
- The 4.4L Northstar featured a sand-cast aluminum upper block with a semi-closed deck design, unlike the 4.6L’s open-deck construction.
- Cylinder bores were reduced to 91mm (from 93mm), improving durability.
- Thicker flanged iron cylinder liners were used to withstand the stress of supercharging.
2. High-Flow Cooling and Oil Management
- Revised coolant passages increased flow, preventing heat buildup under boost.
- A cast-in oil gallery supplied oil to piston cooling jets, reducing combustion temperatures.
3. Unique Cylinder Heads and Variable Valve Timing (VVT)
- Lowered compression ratio to 9:1, optimizing performance with forced induction.
- Reworked combustion chambers for improved efficiency.
- Stronger deck thickness in the heads for increased durability.
- T7 heat-treated aluminum construction for maximum strength.
- VVT (variable valve timing) on all four cams, with unique programming tailored for performance.
These refinements ensured that the 4.4L Northstar could handle extreme loads without sacrificing longevity or reliability.
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The Eaton Supercharger: Power on Demand
One of the defining features of the 4.4L Northstar was its supercharger.
- Designed by GM Powertrain and manufactured by Eaton.
- Roots-type blower with tri-lobe rotors, optimized for smooth power delivery.
- Integrated liquid-to-air intercooler, cooling the compressed air before it entered the engine.
The result? Instant throttle response, massive mid-range power, and relentless acceleration.
Fuel was delivered via dual stainless-steel fuel rails, ensuring a consistent fuel supply under heavy loads.
Why the STS-V and XLR-V Are Rare Collector’s Cars Today
Despite their engineering excellence, both the STS-V and XLR-V were discontinued after 2009. Their low production numbers make them highly desirable among collectors today.
Production Numbers:
- STS-V: 2,440 units (2006-2009)
- XLR-V: 2,188 units (2006-2009)
- 2009 models are exceptionally rare:
- 96 STS-Vs produced
- 239 XLR-Vs produced
With such limited production, these V-Series models have become hidden gems in the Cadillac performance lineup.
Conclusion: The Legacy of Cadillac’s First V-Series Lineup
The Cadillac CTS-V, XLR-V, and STS-V marked a turning point in Cadillac’s history, proving that the brand could compete with the best high-performance vehicles in the world.
✔ The CTS-V put Cadillac on the performance map, blending American muscle with European refinement.
✔ The STS-V and XLR-V showcased Cadillac’s ability to innovate, introducing supercharged luxury performance vehicles.
✔ The 4.4L Supercharged Northstar V-8 remains one of Cadillac’s most exclusive and well-engineered engines.
While the XLR-V and STS-V flew under the radar, they now stand as rare and collectible performance machines, representing a unique chapter in Cadillac’s storied history.
With the modern Blackwing V-Series carrying Cadillac’s performance legacy forward, enthusiasts will always look back at the first-generation V-Series as the beginning of a new era—one where Cadillac redefined what it meant to be an American luxury brand.
