Aside from delivering an all new car for 2015, Ford presented Mustang fans with an additional conundrum. It offered up two performance oriented engines in the regular Mustang lineup, outside of the Ford Performance (formerly SVT) purview. The Mustang GT remains the top dog, blue collar Mustang, with 435 hp and 400 lb-ft of torque on tap from a slightly revised Coyote 5.0. Like a page out of 1985, Ford, also offered up a turbo 4-cylinder version of the Mustang, the EcoBoost. With just 2.3 liters of displacement, the small four-pot generates 310 hp, and a very V8-ish 320 lb-ft of torque. While some purists shudder at the idea of anything but a V8 between a Mustang’s fenders, many enthusiasts are left to consider the EcoBoost for its respectable power numbers, lighter weight, and even its fuel economy.

Most of you reading this are probably already familiar with our Project 5-Liter Eater, our 2015 Mustang EcoBoost Performance Pack. Ford recently sent us a 2015 Mustang GT Performance Pack to evaluate for a week. Since we have access to similarly equipped cars in terms of chassis, we thought instead of giving you the standard review with info that you already know, we’d see how these two cars compare side by side when our editors drive them.

Stacking Up The Power And Options

We already know where the two cars stack up in terms of flywheel horsepower, what we wanted to know was how they stack up on the dyno. We turned each car loose on the chassis dyno to find out how much power was making it to the rear tires.

The Mustang GT put down 390.8 hp and 369.7 lb-ft of torque to the rear tires. Our EcoBoost put down a stock number of 273.2 hp and 303.8 lb-ft. That’s a difference of 117.6 hp and 65.9 lb-ft at the wheels . While the EcoBoost is decidedly an underdog in terms of brute strength, don’t let that fool you into automatically thinking the EcoBoost isn’t an enjoyable driver. At a nearly 200-pound weight advantage over the GT, what the EcoBoost lacks in grunt, it makes up for with its more agile steering and turn in, as well as the ability to keep the back end under control more easily when exiting a corner.

The 2.3-liter EcoBoost is less than half the size of the 5.0-liter Coyote, however, and while the V8 makes great noise, and packs plenty of punch, the turbo-4 isn't far behind in terms of driving enjoyment, or horsepower.

Performance Pack

Both of our cars were equipped from the factory with the Performance Pack. On the EcoBoost that means 14-inch front brakes with 4-piston calipers, and 13-inch rear brakes with single piston calipers. It also means the car gets stiffer front springs, a larger diameter rear sway bar, and heavy duty radiator. Inside the car gets an oil pressure and boost gauge. We have to give props to Ford for a boost gauge that actually reads in PSIg, rather than a generic sweeper with no real markings.

Both cars benefit from the all new S550 chassis and Performance Pack upgrades. The Performance Pack includes a heavy duty radiator, stiffer front springs, and thicker rear sway bar. Outside the car gets a spoiler delete, and unique wheels and tires. Brakes are upgraded on both models, as are the gauges.

For the Mustang GT, the Performance Pack includes all of the enhancements the EcoBoost gets, plus even bigger brakes. The front brakes on the GT-PP measure a massive 15-inches, and come with Brembo 6-piston calipers. Inside the GT, in place of a boost gauge, there’s a vacuum gauge. It’s kind of hokey to be honest, who looks at a vacuum gauge? We’re still waiting to find out if someone can remove this gauge and replace it with the EcoBoost’s boost gauge, add boost to a GT, and get the gauge working. The chances are slim since the gauge is controlled by the computer, we can only hope the aftermarket has a patch.

Both cars also receive a wheel and tire upgrade with the Performance Pack, and a set of ZR rated high performance summer only tires. The GT gets 19×9-inch front and 19×9.5-inch rear wheels, 255/40R19 front 275/40R19 rear, tires. The EcoBoost gets 255/40R19 Pirelli PZero summer only tires on 19-inch wheels at all four corners. Both cars get unique EPAS and ABS tuning. The GT also gets a 3.73 ring and pinion and Torsen differential. The EcoBoost gets a limited slip differential and 3.55 ring and pinion.

The Drive

Now that we have the basics out of the way, let’s get down to what you really want to know, how do these two cars stack up on the street? We spent several days and a few hundred miles behind the wheel of both these machines.

Ford has managed to improve every interior aspect of the Mustang, while the S197 wasn't bad, the new model is a much nicer office for your driving pleasure.

Sound

Ford continues their use of the sound-tube on the 2015 Mustang GT. This tube routes some engine noise from the air intake to the passenger cabin. It’s the familiar rumble of the Coyote V8 and its smoothly singing 435 hp. It’s a soundtrack we’re very familiar with in a much more refined setting. We never get tired of hearing the Coyote’s howl, and the revised mufflers for 2015 give it more factory grumble than ever. This engine is especially sweet to us in the higher rev ranges.

With the exception of the 5.0 badges, and the GT on the rear deck, it's virtually impossible to distinguish the GT from the EcoBoost. Careful eyes will notice a pair of larger tailpipes on the GT, the traditional running horse Mustang badge on the EcoBoost, and unique wheels to each model.

In the EcoBoost, you just can’t get past the fact that you’re in a 4-cylinder. There’s no escaping the buzz and clatter. While Ford does their best to manage the sound with their active noise system, piping in other sounds through the speakers, it’s still a four-banger. What we do like is the whirring the turbo makes when you load the engine up and get your foot all the way down on the throttle. That is perhaps the most satisfying sound we can hope for from the stock EcoBoost.

Power

The Coyote is always satisfying, never failing to deliver the promised power with the jab of our right foot, and quick work of the clutch on occasion. You can easily get this car out of shape on demand with your right foot, and if you want to get sloppy and sideways when the wheel is cut, just apply more pressure with your right foot. The EcoBoost is surprisingly satisfying here as well. We never have trouble getting into boost quickly, and once there, this car can give a lot of older V8 musclecars a run for their money. The EcoBoost’s low peak power (around 5,000 RPM) and torque come on fast, making it incredibly satisfying to drive. We can get this car to bark tires going into third gear, and if we’re not careful, the traction nannies will try to reel us in on a fast takeoff -as soon as boost hits, wheel spin starts -even from a roll in third gear.

Both cars use a variant of the Getrag 6-speed manual transmission. In spite of some of the gripes we’ve heard, it’s the right transmission for these cars. Shifts are smooth, satisfying and precise. There’s a click-click motion on either car, and you always know you’ve hit the next gear. Gone are any previous worries about shifting under power, or other problems. This transmission loves to row.

While the EcoBoost has a much lower first and second gear ratio, the truth is it could use some more thought on gears 3, 4, and 5. While running back roads, through hills, and sweeping curves, we sometimes found ourselves hunting for the right gear until we got to know the car a little better. While cup holder placement is good on both cars, if you’re trying to not knock your big gulp or latte out of the holder while you hit the next gear, going to 4th when you were planning on 6th can become an issue.

Handling Prowess

Both of these cars excel at handling, especially when compared to their outgoing solid rear axle predecessors. The larger tires, better brakes, and suspension enhancements of the Performance Pack really shine when you push either car towards the limit. Side by side, these cars can both hang together in the corners. The GT has the grunt to run away through the straights, and perhaps even on corner exits. However, the EcoBoost feels better balanced due to its 200-plus fewer pounds on the nose of the car. That weight savings pays off in corner entry speed, and through the apex. Without the brute grunt of the V8, the EcoBoost can get deeper into the throttle without getting out of shape. For a skilled driver this pays off on the autocross, and the EcoBoost can log at least identical numbers to the GT if not surpass them in some cases.

Both cars would make excellent track day machines, if we were going autocross, we’d pick the EcoBoost for its balance and nimble front end. This car has less tendency to feel like the weight of the front end will cause it to understeer. For the open track, we’d take the GT for its horsepower, straight stretch speed capability, and its bigger brakes on the performance package to bleed speed even faster.

Verdict

Ford has done an outstanding job of taking the Mustang to new heights with the S550 platform. For a daily commuter, the EcoBoost is a blast to drive, gets solid gas mileage, and is mod friendly. The GT is also commuter friendly, with decent fuel economy, and plenty of power whenever you want it. There’s no way to beat that Coyote horsepower and rumble straight off the showroom floor, and if that’s what gets your blood pumping, the GT is the only way to go.

That being said, the EcoBoost feels more refined, and is sure to catch many would-be competitors by surprise at stop lights or even at track events. There’s something to be said for its lighter weight, and better balance. This car would make a great street sleeper, or autocross warrior. The EcoBoost’s much better fuel economy, even with spirited driving, and relatively low entry price, make it an attractive daily driver for the blue collar crowd or weekend warrior who wants to race on a budget.

We’d take either car for a daily driver, and in fact we already have with our choice of an EcoBoost Performance Pack for our own project car. That doesn’t mean we don’t love the GT and the 5.0 as well, it just means that we find the EcoBoost as satisfying of a car to drive as the GT.