Everything About the S550 Mustang (2015-2019) Submodels

2.3L EcoBoost Engine Specs & Info

• 310 HP & 320 TQ
• Increase to 350 TQ for 2018 model
• Direct fuel injection
• 21 mpg city / 31 mpg highway

3.7L Cyclone V6 Engine Specs & Info

• 300 HP & 280 TQ
• 5 horsepower decrease from precious year
• Twin-independent Variable Camshaft Timing (Ti-VCT)
• 19 mpg city/28 mpg highway
• Base model engine
• Discontinued for 2018 model year

5.0L Coyote V8 Engine Specs & Info (2014-2017)

• 435 HP & 405 TQ 
• Boss 302 derived cylinder heads and forged connecting rods
• Redesigned camshaft and valve springs
• 11.0:1 compression ratio
• 15 mpg city/25 mpg highway

5.0L Coyote V8 Engine Specs & Info (2018 and on)

• 460 HP & 420 TQ
• Direct & port-fuel injection systems
• 7,400 rpm redline (7,000 rpm in 2017)
• 12.0:1 compression ratio
• 15 mpg city/25 mpg highway

5.2L Voodoo V8 Engine Specs & Info

• 526 HP & 429 TQ
• Flat-plane crankshaft
• Tremec TR-3160 six-speed transmission
• 8200 rpm redline
• Equipped only on GT350 models
• 14 mpg city/21 mpg highway

Following a ten-year run of Mustangs on the S197 platform, the Blue Oval manufacturer introduced the new S550 for the 2015 model year. The biggest news regarding the new ‘Stang was the use of independent rear suspension (IRS), which was shied away from on the previous platform because of cost. The front of the S550, ditches a traditional single A-arm setup for a two-link system with separate ball joints, which paid dividends to the car’s steering geometry and handling capabilities.

Ford directly carried over the 3.7L Cyclone V6 base-model engine from the previous year, though it lost five horsepower in the process. The GT’s 5.0L Coyote V8 from 2014 was also placed in the S550 GT, but it received a horsepower boost (to 435 horsepower) thanks to performance parts derived from the outgoing Boss 302 engine. These upgrades included forged connecting rods, cast versions of the Boss 302 cylinder heads, updated valves, and more.

In 2018, the Coyote was updated again, now with direct and port-injection systems, a raised redline of 7,400 rpm, and a higher compression ratio of 12.0:1. That said, the horsepower was boosted to 460 horsepower and torque increase to 420 lbs-ft of torque.

With the introduction of the S550 in 2015 also came a brand-new engine, the 2.3L EcoBoost inline-four. The turbocharged, direct injected powerplant cranked out a significant 310 horsepower while achieving strong fuel efficiency. Impressive stuff.

• Introduction of independent rear suspension (IRS)
• New 2.3L EcoBoost Inline-4 engine
• Updated, more-powerful 5.0L Coyote engine

The change to the S550 platform was a restyled exterior package, which gave it an aggressive appearance. The new ‘Stang’s rear end received wider shoulders, modernized tri-bar style tail lights, and a black decklid panel.

Up front, the S550 comes with larger grilles than the S197 to improve cooling, revised hood vents, and aggressively-shaped headlights. The S550 also comes with lower side skirts, which give it the appearance of riding much lower to the ground. Additional roof lines carry on to the hood, giving off an aggressive look.

Beginning for the 2015 model year, Ford introduced the Shelby GT350—powered by a 526 HP 5.2L Voodoo V8 engine. Aside from a more-powerful powertrain, the GT350 gets various other modifications to its chassis and overall package.

The suspension gets track-focused tuning, larger brake rotors with Brembo calipers, a lightweight Tremec six-speed transmission, and a carbon fiber reinforced radiator support piece which directs cooling channels to various components under the hood.

A limited-edition, track-focused GT350R is also produced, which sees a significant weight reduction in comparison to the “standard” GT350. Ford chose to ditch the A/C system, stereo, rear passenger seats, backup camera, and exhaust resonators.

Unique to the R model is a set of carbon fiber composite wheels, which weigh only 18 pounds a piece (similar aluminum rims weigh roughly 33 pounds). It’s also equipped with a larger front splitter and rear wing than the GT350 as well as a D-shaped steering wheel.

• 5.2L Voodoo V8 Engine
• Track-tuned suspension package
• Carbon fiber wheels (R model)
• Brembo braking calipers

Aftermarket Downpipes on the EcoBoost: Looking to give your EcoBoost Mustang a little extra pep? Upgrading its downpipes will allow your engine to breathe much more freely, which will help increase horsepower.

There are options out there, like off-road downpipes or high-flow downpipes, so take into consideration your desires and where you live when choosing your new downpipes. States with strict emission standards like California might even deem catted aftermarket downpipes illegal.

Rear Window Louvers – Give Your S550 a Classic Look: Itching to have your S550 look more like the Mustangs of the 1960s and 1970s? Throwing on a set of rear window louvers will offer up that timeless look, plus do their part in keeping the climate inside your Pony from getting too hot. Louvers are often offered in both plastic and metal options and can be painted to match the body color.

Increasing Power with Custom Tunes: Tuning your Mustang via a secondary computer (such as a SCT or Bama unit) can pay dividends to your ‘Stang’s power output. These devices typically come with pre-loaded aftermarket tunes, but custom tunes can also be created.

On an S550 with the EcoBoost engine, most programs can add an additional 40 horsepower and 40 lbs-foot of torque, adjust boost control, improve throttle response, remove the OEM speed limiter, and revise shift points in the transmission.

The 5.0 Coyote has also been known to benefit from an aftermarket tune. Increased output (by about 25 horsepower), altered throttle response, improved air intake control, calibration of the speedometer for aftermarket rear end gears, and revised shift points are products of a tune.