Ford’s latest V6 and V8 engines stand out for their good performance and even better fuel economy, but the new mills also stand out due to their glaring lack of direct-injection. DI is quickly becoming the industry standard but, as Ford found out during development, the latest technology isn’t always the best.
We’ve been lead to believe that direct-injection is better for fuel economy in all instances, but this purported fact doesn’t hold true for all applications. “When the program started, it [the new Duratec in the Mustang] was a direct-injection engine,” Greg T. Johnson, a powertrain integration manager whose responsibilities include both engines, told The Car Connection.
But after a number of tests, Johnson’s team realized they could better manipulate intake air temperatures – thereby increasing power and fuel economy – by omitting the DI technology.
Johnson admits the test engines with direct-injection helped with knock, but didn’t make a marked difference in overall performance – especially when the overall cost was entered into the equation. “Yeah, it helped us a little bit with knock, but it wasn’t that much for all the cost,” he said.
The results seem to speak for themselves. Ford’s new 3.7L V6 engine develops 305 horsepower, besting General Motors’ highest output 3.6L DI V6 by 1 horsepower. Ford’s V6 also clips GM’s by 1mpg highway. Ford’s latest 5.0L V8 performs comparatively as well, developing a healthy 412 horsepower and returning 25mpg.
Although adding direct-injection to the engine range would seem like the next logical step in the coming years, Johnson says there are no such plans in the works.
