- Traditional fuel injection systems pre-mix gasoline and air to cause the explosion that powers the engine's pistons. This process is done as the gas and air mixture enter cylinders from the fuel injectors and intake manifold. The direct fuel injection process does not pre-mix gasoline and air before it's ignited. Instead, gas comes directly into the cylinder from the fuel injectors while only air is sucked through the intake manifold.
- In 2008, G.M. started using direct fuel injection on the 3.6L V-6 CTS. The system, according to dealers, has increased engine horsepower from 255 hp to about 300 hp. Fuel efficiency, because of direct fuel injection, has seen increases of 3 to 5 percent. Cadillac models using direct fuel injection systems also run on 87 octane fuel, while traditionally, premium fuel was required for optimum performance.
- Cadillac direct injected systems are built with a newly-designed stainless steel fuel line that flows to the fuel rail. This accommodates the high pressures involved in direct injection. According to Cadillac, it has also upgraded fuel pumps on direct injection engines to pump more than 1,700 psi of pressure to complete the injection process. The pump is also made to operate at lower pressures when idling (see Resources).
