The 2006 Cadillac XLR-V – the newest addition to the luxury nameplate’s growing family of high-performance V-Series vehicles – establishes a new benchmark for the ultra-luxury class of high-performance roadsters in power, performance and personal amenities.
At the heart of the XLR-V is the new, 4.4-liter version of the Northstar engine outfitted with a positive displacement intercooled supercharger. The dual overhead cam (DOHC) V-8 engine delivers the highest horsepower rating of any Cadillac engine to date.
Called the Northstar V-8 SC (supercharged), the engine produces 440 horsepower (328 kW) at 6400 rpm and 425 lb.-ft. (576 Nm) torque at 3600 rpm (power and torque figures estimated) – and the engine’s power is underscored by its ability to deliver 90 percent of its peak torque between 2200 and 6000 rpm.
The Northstar V-8 SC generates 120 horsepower (90 kW) and 115 lb.-ft. (156 Nm) of torque more than its naturally aspirated counterpart, while its specific output of 100-horsepower-per-liter makes it one of the world’s highest specific output production V-8 engines.
However, the Northstar V-8 SC used in the XLR-V is more than just power and torque. The DOHC engine includes variable valve timing that enables outstanding top-end performance while maintaining the expected refinement and quality associated with a luxury marque.
The aggressive torque curve enabled by the choice of a supercharged engine gives the XLR-V acceleration capable of placing it firmly in the under-5-second-club for 0-to-60 time – a signature capability of V-Series vehicles.
The refined shift feel is enabled by careful electronic calibration of both the engine and transmission. During shifts, power is instantaneously lowered, then ramped back up carefully to make gear changes virtually unnoticeable.
The air induction system on the XLR-V was redesigned to address packaging needs created by the larger engine and addition of the supercharger.
These modifications increased the flow of air to the engine by 30 percent, funneling it from the front air intake over the radiator and to the supercharger via two ducts, which converge into one prior to reaching the supercharger so only one mass air flow sensor is required.
The system was designed to be as free flowing as possible, bringing in the maximum amount of air to the supercharger. Each duct has been carefully tuned to minimize supercharger whine and resonance in order to achieve the most pleasing intake sound quality.
The exhaust system features a unique muffler design, which effectively combines the construction of a more conventional muffler with a high-performance flow-through design. In order to keep sound levels at a pleasant, throaty pitch during everyday driving on streets and expressways, the exhaust is routed through a series of internal chambers that muffle sound levels . During more aggressive driving, a vacuum-actuated Pierburg valve in the muffler opens to allow straight exhaust flow-through. There are some perforations in the pipe to allow some dissipation into the other muffler chambers, but the overall effect is to reduce backpressure and increase power.
The Northstar V-8 SC is mated to the all-new Hydra-Matic 6L80 six-speed automatic transmission – the first use of General Motors’ new six-speed automatic in a rear-mounted configuration.
The 6L80 – the only transmission offered on the XLR-V – is one of the most technologically advanced automatic transmissions in the industry, using clutch-to-clutch operation and an advanced integrated 32-bit transmission controller to deliver smooth and precise shifts. In addition, a wide 6.04:1 overall ratio spread enhances performance and fuel economy.
Source: Cadillac press