DRIVEN: 2015 Ford Mustang Ecoboost



Once inside the car, the ergonomic features of the Ecoboost are virtually identical to the Mustang GT discussed in my previous review.  Like the GT, the interior has a higher quality feel with luxurious soft touch surfaces and better materials than its predecessor or even others in its category.  One major difference is that when equipped with the Performance Package, the Ecoboost replaces the GT’s somewhat trivial vacuum gauge with a useful boost gauge in addition to the oil pressure gauge.

Once you press the engine Start/Stop button the inline-4 comes to life and settles into a subdued idle.  There are many criticisms of the sound of the Ecoboost, which is ironic because it’s actually just as loud as the GT and dare I say, sounds just as good?  Now before this statement ruffles your feathers, go and drive one!  A stock GT is extremely quiet which muffles the signature V8 growl that everyone loves, thus the majority of the noise you hear inside either the GT or Ecoboost car is actually the induction noise.  Ford did this on their previous Mustang as well by using a pipe to connect the car’s intake to the cabin to improve sound just like McLaren does with the 12C and Porsche does with the 911.  I still wonder if there are strict idle and low rpm decibel levels that all manufacturers have to abide by which results in cars with almost no character from the exhaust unless equipped with active butterflies like more expensive cars have.

Now if you uncork the V8 with an aftermarket exhaust, I understand and would agree that Ford’s 5.0 is a fantastic sounding engine.  But I come from a tuner background dominated by small displacement forced induction cars.  To me, the sound of a freed up Ecoboost with its complex symphony of a raspy 4-cylinder, the whirl of the turbo spooling up and down, and the crackling overrun on deceleration is very satisfying.  Many turbo import buyers will feel right at home here, it’s a different world than the roar of a V8 and I enjoy the uniqueness of both.



Having driven almost every variant of Mustang that was made in the last 25 years (from a 5.0L LX to GT500KR) and racing them professionally for the last 7, there’s no mistaking that you’re driving a Mustang when behind the wheel of a 2015 Ecoboost.  On the road, the overall ride quality is similar to the GT, which is a huge improvement compared to the previous solid axle S197 chassis over bumps and rough roads.  The new S550’s independent rear suspension and dual ball joint strut front suspension have far more anti-dive and anti-squat than its predecessor which results in a much flatter, more stable, and composed driving dynamics.  Like the GT, the Ecoboost has departed from its stereotypical ‘Ponycar’ background and has become a more refined, solid, and a higher quality sports car while retaining a familiar Mustang feel to it.


Boss 302R RacecarThis is the #15 BOSS 302R that I compete in the IMSA Continental Tire Sports Car Challenge series for Multimatic Motorsports.  The series is as close to showroom stock as you can get in professional racing and it is essentially a caged 444hp 5.0L BOSS 302 street car, which is arguably the best performing Mustang to date.  While a S550 Mustang GT equipped with the Performance Package is faster than the Boss 302 street car on a racetrack, it does not quite equal the excitement of the Boss’ suspension tuning which is more engaging and driver-focused.  We will see if the new Shelby GT350 is a worthy successor to the Boss’ driving standards.

The Ecoboost weighs roughly 150lbs less than the GT and a lot of that weight was taken off the front.  The Ecoboost has a slightly better 52/48 % Front/Rear weight distribution compared to the GT’s 53/47% distribution.  Although 1% does not sound like much, the Ecoboost’s front end feels much lighter and more responsive than the GT.  Where the GT is limited by understeer on corner entry and mid-corner, the Ecoboost is better balanced with noticeably less understeer.  While the GT has an additional 125 horses and 80lb-ft of torque which makes on-throttle rotation easy, the Ecoboost spools up with just enough power to overwhelm the rear 255 PZeros, sending the car into smile-inducing powerslides.  I was very happy with the power to grip ratio of the Ecoboost and found it to be a really fun car to drive.  With its more balanced chassis, it may be more fun than the GT on a tight, twisty mountain road.


Ecoboost front fasciaAir curtain hole
Other than the grill insert, the front Fascia of the Ecoboost is virtually identical with the Mustang GT, including this slot which creates an air curtain that accelerates the air around the front tire, evacuating the high pressure that builds up in front of the tire and improving airflow around the body.  While the black splitter sticks out as far as the GT, the Ecoboost’s splitter does not extend as low and the under aero is vastly different.
Standard ecoboost airdamEcoboost PP airdam
The standard Ecoboost (left) has this “A” shaped flexible airdam, the Performance Package equipped car (right) has a more traditional shaped airdam that’s used on the Mustang GT.  Unfortunately the Ecoboost PP does not have the front ‘diffusers’ like the GT PP equipped cars have.
Standard ecoboost trunkEcoboost PP trunklid
Like the Mustang GT, the standard Ecoboost (left) has a small optional decklid spoiler that does not appear to be that functional, while both the Performance Package equipped GT and Ecoboosts have a mandatory spoiler-delete (right) which is an interesting decision.

Now let’s compare the Ecoboost to a popular track day car, the 2,800lb Scion FRS/Subaru BRZ twins.  Despite being much slower in a straight line (hitting 60 in well over 6 seconds) due to a modest 200hp and 151tq, the FRS/BRZ has a lighter and more nimble chassis than the Mustang thanks to the flat-4 engine’s lower center of gravity. In order to increase the car’s fun factor, Scion and Subaru use skinny 215 tires to reduce the total grip of the car which enabled for on throttle oversteer.  Once you put stickier or wider tires on a FRS/BRZ, sustained powerslides are all but impossible.

The FRS/BRZs are much smaller cars with less trunk room than the Ecoboost and while you can fit 4 people in a Mustang in a pinch, the rear seats of the FRS/BRZ are as worthless as those in a 911.  I like the FRS/BRZ on track, and while econoboxes have a minimalist charm to them the interior looks and feels simpler, lighter, and cheaper. The econobox feel is also reflected in its harsh, jarring and unrefined ride quality. Despite various aftermarket parts which attempt to improve the ride, nothing really fixes the inherent suspension design’s lack of compliance, and many owners echo this complaint.


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