Tom Wilson
January 27, 2014
Photos By: Courtesy of Ford Motor Company

Powertrain

Of all major systems, the '15 Mustang's powertrain is the most familiar to we enthusiasts, but there is still plenty new. Ford's overall statement on the '15 underhood family came from Dave, who said he was, "happy to say we have the most powerful, fuel-efficient engine lineup in the history of Mustang."

Entry-level Mustangs retain the familiar 3.7- liter V-6 with some, as yet unspecified, detail improvements. Ford would not talk specifics, but the V-6 is the least changed engine and clocks in at a preliminary spec of 300 horsepower at 6,500 rpm and 270 lb-ft at 4,000 rpm.

Next is the first rear-drive application of an Ecoboosted four- cylinder at Ford, an all-new 2.3-liter Ecoboost four-banger. The new 2.3 is also rumored to appear in a new Focus RS in Europe, but Dave noted this Ecoboost 2.3 is specifically designed for "Mustang performance," and itwas confirmed by him to make more power than the V-6 at a preliminary 305 horspower at 5,500 rpm and 300 lb-ft of torque from 2,500 to 4,500. No matter the final rating the 2.3 will play the expected Ecoboost dual role of performance upgrade from the base V-6 combined with a fuel economy boost compared to the 5.0-liter V-8. In fact, it's said to offer a "substantial" fuel-economy improvement over the outgoing 3.7-liter V-6.

Could this be the first Mustang engine to exceed the old 5.0 H.O.'s pushrod thrust while doubling its mileage?

In any case, the hardware confirmed by Ford is enticing. A stout steel crankshaft is on board, signifying a need to contain meaningful power, along with a high-flow, three-port cylinder head designed to gather and pulse the exhaust stream to the twin-scroll turbocharger for quicker spooling (think of an impact gun compared to a breaker bar energizing the turbine). This is done by branching the exhaust from cylinders two and three together while letting cylinders one and four exhaust independently. Keeping with modern practice this is done completely within the cylinder head casting. There is no exhaust manifold in the traditional sense, with the turbocharger simply bolting to the extended side of the cylinder head. Ford calls this an Integrated Exhaust Manifold and says it reduces turbo lag, and allows for longer exhaust valve timing for increased performance because there is less reversion (back flow) from other cylinders.

Perhaps more telling, the integrated exhaust plays an important role in quickly spooling the 2.3's big turbocharger. Sized larger than normal Ecoboost practice to make good top-end power, Ford found the IEM key in reducing the big unit's turbo lag.

Of course, the major attraction to a four- cylinder turbo in a performance car is not hitting the extremes in any one area but in tossing all the darts relatively close to the bulls eye. Thus, a favorable power-to-weight ratio, contained cost, good fuel economy, and excellent weight distribution are all factors in considering how the 2.3-liter Ecoboost Mustang will perform. A flat and distinctly muscular torque curve is also a given with an Ecoboost engine. Dave said the 2.3 "is extremely rewarding and well-balanced. It will definitely put a smile on your face. It is absolutely worthy of wearing the Mustang badge; we're really proud of this engine... it's going to be a great addition to our lineup."

While his boss, Raj Nair, was more specific, saying, "At the highest level, my favorite Mustang to drive is the Boss 302. So the target for the team was to get that level of balance that we have with the 302 across the total lineup.

"The 2.3 in particular, as well the 3.7- and 5.0-liter, not only achieve that level of balance, but the window that you have between steering control, throttle control, managing the weight and rotating the vehicle in the 302, I wouldn't say it's narrow, but you have to be on your game at 10/10 (driving at the limit). What we have now with the [2.3] is the window... is much wider. It is easier to drive the vehicle and enjoy the vehicle." Or, as Raj summed it up, "Flatter the novice and reward the expert."

We can only think the 2.3 Ecoboost Mustang will have the dynamic range to deliver on the unrequited promise of the mid-'80s SVO Mustang, a car that showed fleeting glimpses of glory but couldn't deliver the needed refinement or performance at both ends of the tach. Certainly it has been performance tuned and will serve as the desirable option for a newer generation fans who don't necessarily like or want a V-8.

Most exciting of all, the Coyote is evolving using parts and experience from the Boss 302's vaunted Roadrunner engine. Again, Dave laid out the highlights: "Of course, the 5.0-liter, the engine that's at the top of our lineup, we are not leaving that alone. We are improving its fuel performance, and overall power. "

"We taking learnings from the Boss 302, and even, in some cases, some components out of the Boss 302. We're making the engine breath better," he said. "Larger intake and exhaust valves is one improvement... Revised camshafts with higher valve lift and a new cylinder head with improve port flow [is another improvement]. All that we learned from the Boss 302."

"Now, some of the components we're using are the Boss 302 valve-springs and connecting rods..." he added. "We're also adding a standard air-to-oil cooler because the top speed across the entire lineup on Mustang is being increased, with the V-8 hitting 155 mph."

"So, you've seen us take the 5.0-liter from 412 to 420 horsepower, now we're going to take yet another step forward. We always put the and solution out there, so we're improving the fuel as well," he explained. "And how are we doing that? We have a new intake manifold with remote control valves... That allows us to control the combustion chamber and optimize it to give it more stability at idle and it will improve our total emissions and fuel economy. And then we have mid-lock variable cam timing phasers as well that allow us to more... precisely control the airflow."

More specifically Dave confirmed the new 5.0 cylinder head is not the fully CNC-ported Boss 302 head, which is impossible to build in Mustang GT volumes. Rather it's a new casting incorporating lessons learned from those heads. That said, at press time the projected specs on the revised 5.0 are an obviously conservative 420 horsepower at 6,500 and 396 lb-ft at 4,250 rpm.

All of these engines are married to the same six-speed transmissions in use today, but with significant improvements. The Getrag manual gains improved internals for smoother shifting and improved shifter plane spacing. It is "rewarding and precise," states Dave.

The automatic is re-engineered to reduce parasitic losses and withstand great power and torque. Furthermore, every automatic, with all engines, offers paddle shifting with rev-matched downshifts. These shifts are tuned by the new driving mode selector so Sport gives quicker, more aggressive shifts, and we presume Snow/Wet gives less shocking gear changes.