2015 Ford Mustang: Everything You Need to Know About Its V-6, V-8, and EcoBoost Engines

Official information about the all-new 2015 Ford Mustang has been dripping like coffee made from molasses. The latest caffeine injection, however, was satisfying indeed: intel on the 2015 car’s three engines. We’ve already discussed the output figures, predicted their performance abilities,
and even built the 2015 Mustang of our dreams. Now here are the important details you need to know about all three powerplants:

3.7-liter V-6: 300 hp, 280 lb-ft

This is the DOHC 24-valve engine that comes in the bone-stock, $24,425 Mustang coupe. Actually, every Mustang engine employs dual overhead cams and a four-valve-per-cylinder design. With variable intake- and exhaust-valve timing, another trait carried across the engine range, the V-6 makes 300 horsepower at 6500 rpm and 280 lb-ft at 4000 rpm. Compared with the 2014’s 3.7, the torque peak is 250 rpm lower and max power is down by five ponies. For all intents and purposes, this engine is unchanged.

The 3.7-liter does benefit from the heavily modified drivetrain common to all 2015 Mustangs. The Getrag-supplied MT82 six-speed manual gets revised low-drag synchros and a new, stiffer linkage to improve shift quality. The manual’s shifter also switches from pushing down to access the reverse gate to a lift-up collar on the shifter. (The new style is a global Ford characteristic; the new Mustang will be sold overseas.)

Ford’s in-house final drive was also reworked, with the company fitting 9.8-inch differential internals in an 8.8-inch-sized unit with a stiffer ring, pinion, and case. Those hurting from the loss of an ultra-durable live rear axle should find salve for their wounds in that fact. Manual-transmission cars use an iron differential carrier to combat the impact loads of high-rpm manual shifts, whereas the automatic cars have an aluminum carrier. Both manual and automatic cars employ an aluminum differential cover. For the record, the iron carrier is 24 pounds heavier than the aluminum one.

2.3-liter turbocharged EcoBoost inline-4: 310 hp, 320 lb-ft

A four-cylinder engine will again power Mustangs, but this time not as the base engine. For $1570 over the V-6, Mustang buyers can have a turbocharged and intercooled, 310-hp 2.3-liter inline-four. Now, we’re not saying the V-8 GT detailed below is the best value, but consider that the EcoBoost’s 10 extra horsepower come at a cost of $157 apiece. Plus, according to Ford, the four pot doesn’t save any weight versus the V-6 model. In fact, Ford says the manual four tips the scales at six pounds heavier than the V-6; the automatic weighs six pounds less.

This engine shares some basic layout elements—bore centers and deck height—with other four-cylinder EcoBoost engines, but it’s otherwise basically unique. Although the Mustang’s 2.3 is similar to the 2.3 found in the new Lincoln MKC and the forthcoming Focus RS, the pony car’s version is installed longitudinally. The Lincoln and Focus use a transverse installation, meaning everything from the two-stage variable engine mounts to the intake is different, including the block.

A twin-scroll Honeywell turbocharger is bolted directly to the integrated-manifold head, an increasingly common feature these days. GM has used the integrated design on its high-feature V-6 for a few years, and the VW Group uses a similar setup on its EA888 family of engines. By adopting the first multiple-scroll turbo on a Ford engine, the EcoBoost can spin the low-mass turbine up to speed more quickly, minimizing lag and—equally important—mitigating efficiency- and power-zapping backflow into other cylinders. Direct injection and variable valve timing are in the mix, too. In a quest for durability, Ford installs a forged steel crankshaft and connecting rods. Mahle pistons bolstered with steel piston-ring carriers allow for an increased compression ratio of 9.5:1 versus the 9.3:1 of turbocharged 2.0-liter applications.

In terms of twist, this four-banger churns up 320 lb-ft at 3000 rpm, 40 more—at 1000 rpm earlier—than the V-6. That torque stays rather constant all the way to the horsepower peak of 5500 rpm, where the 2.3 still makes 296 lb-ft. It’s the low-rpm torque that should ultimately make the EcoBoost the quicker of the two non-GT Mustangs.

5.0-liter V-8: 435 hp, 400 lb-ft

Ford’s Coyote V-8 carries over as well, although it receives more substantial changes. Mustang engineers used the low-volume Boss 302’s V-8, a glorious-sounding 444-hp powerhouse, as its performance bogey. Unfortunately, the Boss engine incorporated some expensive manufacturing tricks that Ford couldn’t possibly use in a mass-produced engine, like hollow intake valves, sodium-filled exhaust valves, and CNC-ported heads, so it had to look elsewhere to approach Boss power levels.While the new engine doesn’t quite come up with triple-fours, it does pump out 435 horsepower at 6500 rpm and 400 lb-ft at 4250 rpm, increases over the old 5.0 of 15 horsepower and 10 lb-ft. The extra output was achieved via improved head flow (which Ford was able to accomplish through casting rather than expensive machining), larger valves with increased (Boss 302–spec) lift, stiffer valve springs, the Boss’s forged connecting rods, and some aesthetically pleasing tubular headers. The compression ratio remains 11.0:1, and an oil cooler is now standard. The 5.0 commands an $8500 premium over the V-6, which equates to $63 per additional pony.