To meet these lofty goals the Mustang structure is more
rigid with increased use of high-strength steel, increased gusseting
(especially around the radiator support), and wears a stronger, stiffer, and
lighter front cross member. Greater precision and world-class handling were
clearly on the agenda, and the chassis was made all new accordingly. Of course,
the new chassis is stressed and packaged to work with the all-new IRS. Such
provisions go deep, as the IRS packages completely differently than the
outgoing live axle. It uses a sub-frame mounting system for the differential,
which is based off of the familiar 8.8, and it feeds loads into the unibody at
much different points than the live axle.
To meet these
lofty goals the Mustang structure is more rigid with increased use of
high-strength steel, increased gusseting, and wears a stronger, stiffer, and
lighter front cross-member
Just to be clear about it, there is no provision for a live
axle anywhere in the ’15 Mustang lineup, and for better or worse, we’ve
doubtlessly seen the last live-axle Mustang from Ford. Insiders say
retrofitting a live axle to the 2015 will not be easy. All but dedicated,
mega-power drag racers will likely learn to live with the IRS.
Asked why Ford dropped the live axle, Dave replied with a
little laugh, then said, “It’s just time. I think it is really important as you
decide to take the vehicle global, I think that’s something important to that
strategy.
“We’ve done a lot with the solid axle, we’ve taken it a lot
farther than most people ever thought you could, we love where we’ve been and
what we’ve done, but looking forward and taking the car global, I think that’s
key to the strategy, to have the independent rear suspension. And, you know, when
we decided to do it, we did it right. I mean, this independent rear suspension
is a world-class suspension, and we’re pleased with how it’s performing.”
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 horse-power at 6,500 rpm and 270 lb-ft at 4,000 rpm.
Entry-level Mustangs
retain the familiar 3.7-liter V-6 with some, as yet unspecified, detail
improvements
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 it was
confirmed by him to make more power than the V-6 at a preliminary 305
horsepower 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.
Next is the first
rear-drive application of an Ecoboosted four-cylinder at Ford, an all-new
2.3-liter Ecoboost four-banger
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.
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
“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.”
