Airflow Technology Feeds New 3.6L Cadillac SRX

[Bruce Nunnally]

2012 model delivers more torque across broader range of engine speeds

DETROIT – It wasn’t a breeze, but redesigning the air induction and exhaust systems in the 3.6L direct-injected V-6 engine helps give the 2012 Cadillac SRX the most standard power in its crossover segment.

The new engine is standard on all SRX models sold in North America. It goes on sale this month.

“When we started planning to equip this vehicle with the 3.6L engine, I challenged our engineers to achieve 300 horsepower and maintain fuel efficiency,” said Liz Pilibosian, vehicle chief engineer. “They came back and exceeded the goal with 308 horsepower.”

Engineers made key engine changes and redesigned air induction and exhaust systems to get more horsepower and torque, the twisting force that gets a vehicle moving and what the driver feels when accelerating.

“We wanted to continue our evolution of the SRX by improving the power and acceleration response of the vehicle,” said Steve Kline, lead development engineer. By increasing air intake capacity, Kline said, cooler and denser air is available to the engine, making it more powerful and responsive – especially on hot days in slow city traffic.

The exhaust system improvements are extensive. “It’s all-new from the engine to the exhaust outlets,” Kline said. “From larger diameter pipes to a higher-volume muffler, the system is tuned to pull exhaust gases out of the engine at 1,200 to 3,000 RPM. This means more torque when you need it most.”

SRX drivers will notice less shifting of the automatic transmission and more torque across a broader range of engine speeds, rotations per minute or RPM. This provides greater confidence for passing and freeway maneuvers and an overall driving experience more responsive to driver input.

Conventional wisdom would suggest that larger engines are louder, given that 308 horses under the hood can make a lot of noise. Engineers countered that with a variety of soundproofing materials. These acoustic treatments cover the instrument panel, center console, engine compartment and wheel wells.

As chief engineer for the SRX, Pilibosian is responsible for performance and testing, a role that suits her wrench-in-hand personality.

“I’ve always been mechanically inclined,” she said. “When I was younger, I liked to build things. My dad, an engineer himself, helped guide me toward an automotive career.”