2009 Cadillac CTS-V

For 2009, the Cadillac CTS-V (fig. 1) offers a number of new and improved features, led by a supercharged V8 that offers 556 horsepower (415 kW) at 6,100 rpm. The vehicle's potential is emphasized by the domed aluminum hood and new front fascia with larger grill intakes for improved cooling.

Here are some highlights.

6.2L V8 ENGINE (LSA)

(fig. 2)

558 hp @ 6100 rpm

551 lb-ft @ 3800 rpm

Supercharged (1.9 liter per revolution, 9 psi boost)

Cast aluminum block

Forged steel crankshaft

9.1:1 compression ratio

Forged powder metal connecting rods

Piston oil spray cooling

Rotocast aluminum cylinder heads

Cast aluminum intake manifold

2 valves per cylinder

Hydraulic roller valve lifters

Sequential fuel injection

Supercharger

The LSA V-8 is equipped with a sixth generation Eaton supercharger that features Twin Vortices Series (TVS) supercharging technology (fig. 3).The supercharger displaces 1.9 liters per revolution and generates a maximum boost pressure of 9.0 psi (0.52 bar).

The four lobe rotor design (fig. 4) enhances quietness while also optimizing the performance and overall efficiency of the engine. Compared with earlier three lobe rotor designs, the amount of power needed to operate the supercharger is reduced by about 35%.

Intercooler

The LSA's intercooling system uses a single aluminum tube and fin heat exchanger mounted above the rotors in the supercharger case (fig. 5). Air pumped by the supercharger flows down to the intake ports on the cylinder heads. The intercooler cooled by its own coolant circuit, with a reservoir mounted in front of the radiator.

LSA Oil System

The oil pump has a capacity of 33.8 gallons per minute, for efficiency during extended high-rpm operation. The six-quart oil pan is fitted with a liquid-to-air oil cooler (fig. 6).

TRANSMISSIONS

Two 6-speed transmissions are offered, both manual and automatic.

Manual Transmission

The new TR6060 manual transmission (MG9) (fig. 7) is based on the proven Tremec T56 six-speed used in the previous CTS-V, but is upgraded to handle the LSA engine's increased torque output.

It features both double-cone and triple-cone synchronizers. A short-travel shifter mechanism is used. Bearings are used on the shift rail in place of bushings. This reduces friction, making the shifter feel lighter and more direct.

Twin Disc Clutch

A Luk 240 mm twin disc clutch uses a pair of smaller diameter clutch discs that have less inertia than a single, larger diameter disc. This delivers improved clamping power and excellent shift effort. A dual mass flywheel is used for smooth, rattle free performance.

Automatic Transmission

The Hydra-Matic 6L90 six-speed is the first automatic transmission offered in the CTS-V (fig. 8).

The transmission is a heavy-duty version of the 6L80 six-speed automatic. A strengthened input gearset has two additional pinion gears (total of six). And a strengthened output gearset uses wider gears than the 6L80.

A twin-plate torque converter clutch accommodates the torque output of the LSA engine. This is the first twin-plate configuration used with GM's 300-mm torque converter. Like the dual-disc clutch of the six-speed manual transmission, the twin-plate converter clutch provides additional clamping power.

Tap-Up/Tap-Down Shift Controls

Standard steering-wheel-mounted paddles are provided for tap-up/tap-down shift control. There is also a console-mounted gear shifter control.

DRIVELINE

The driveline is mounted on a large steel subframe that provides isolation from the rest of the chassis (fig. 9). The rear axle and differential assembly of the CTS-V are upgraded to handle the additional torque. The GT4 axle ratio is 3.73:1 with the manual and 3.23:1 with the automatic. The driveshaft has a larger outside diameter and thicker wall, the limited-slip differential housing is made of cast iron and has offset mounts.

TIP: Two different size half shafts are used to counteract axle hop. The left side is 55 mm, and the right side is 35 mm.

A Rear Differential Cooler kit is available through Service Parts (TechLink October 2008).

TIRES AND WHEELS

Michelin Pilot Sport 2 tires (255/40R-19 front and 285/35R-19 rear) on 19-inch alloy wheels were developed specifically for the CTS-V (fig. 10).

MAGNETIC RIDE CONTROL (MRC)

Magnetic Ride Control (MRC), also known in SI as magneto-rheological real time damping (MRRTD), independently controls the fluid viscosity in each of the four shock absorbers during hard cornering, acceleration, braking and other dynamic maneuvers.

The driver can select one of two Magnetic Ride modes: Tour for grand touring or Sport for performance driving. Both modes use the same algorithms but have different calibrations.

A new type of magnetic fluid and a new piston shape inside the shock allow the Touring setting to be even softer, and the Sport setting even firmer.

The CTS-V also has a lower ride height than the CTS.

BRAKES

The J56 heavy-duty antilock brake system uses Brembo 14.6-in. six-piston brakes in front and 14.4-in. four-piston brakes in the rear.

A J63 competition brake package uses race-style front rotors that are bolted together, unlike the regular CTS-V front rotors which are cast 2-piece rotors. The competition package also includes red-painted Brembo brake calipers (fig. 11).

Electric Parking Brake

An electric parking brake is standard on the 2009 Cadillac CTS-V. An electric park brake (EPB) release switch replaces the park brake pedal and release handle used on the manual system.

The electric park brake module assembly has an internal motor, apply actuator, release actuator, and temperature sensor. The control module also contains the logic for applying and releasing the parking brake when commanded by the parking brake switch.

See the July 2008 issue of TechLink for greater detail.

INTERIOR FEATURES

The instrument panel has a boost gauge, lateral G meter and added tracers on the tachometer and speedometer.

The seat inserts are covered in a suede-like microfiber cover. Metallic throttle, brake and clutch pedals are also available with the microfiber package.

Performance Driving Seats

Optional performance driving seats provide excellent support for spirited driving (fig. 12). These new, 14-way adjustable performance seats include suede seat inserts and pneumatic bolster controls in the seat cushion and backrest.

A microfiber covered steering wheel and shifter are optional with the performance seat package.

Passenger Presence System

Starting with the 2009 model year the CTS-V (and CTS as well) is equipped with a Body Sense PPS system.

This system uses input from a flexible sensor (fig. 13) that emits a low level electric field to discriminate between an infant in a child restraint and an occupant sitting directly on the seat. The Body Sense PPS system will enable (turn ON) the passenger frontal airbag for a wider range of front seat occupants than the system it replaces.

TIP: Customers should be aware that some electronic devices placed on the front passenger seat (computers, MP3 players, cell phones, etc.) may interfere with the electric field generated by the system, causing it to enable (turn ON) the passenger airbag and turn on the safety belt reminder light and chime, even though the seat is not occupied.  The electronic device does not necessarily need to be turned on to cause this condition. If this happens, have the customer remove the electronic device from the seat.

- Thanks to Toby Davis