Under The Hood: 2017 Ford Focus RS

Ford-Focus-RS-Engine-1m

Sharing the same displacement and overall design of the 2.3-liter EcoBoost engine of the Ford Mustang, the specific output version found in the Ford Focus RS does have a number of significant differences that help it achieve a higher horsepower and durability level.

Designed for a transverse mounting, it features a cast aluminum block with more robust cast iron cylinder liners and an aluminum head. In this application the engine produces 350 horsepower at 6,000 rpm and 350 pound-feet of torque at 3,200 rpm and steady all the way to 4,500 rpm.

Though it all sounds quite exotic the engine looks rather mundane with the cover off, most of the external hardware and apparatus being made of black composite plastic.

Following the airflow, the intake charge starts up front behind the grille and splits into a somewhat complex air filter box that features an open element cylindrical air filter. It’s dressy with the RS badge cast into a mesh honey comb grate.

From there the air travels through a plastic tube over to the rear of the engine, also stamped with the RS logo. It then heads around to the rear of the engine to a unique Honeywell twin-scroll fixed geometry turbocharger with larger compressor than that found on the Mustang.

It’s hard to see from above but the turbocharger mounts to a head with an integrated exhaust manifold that enables better thermal efficiency. From there the intake air travels under the engine to a large air-to-air intercooler mounted behind the grille up front and down low.

After cooling the air heads back up into the throttle body and up through a composite intake manifold that is again unique from that found in the Mustang with a higher and better managed flow. It heads into the cylinders which are managed by twin variable cam timing.

Ignition is fired by a now traditional coil on plug system and direct-injection. Not much of the fuel system is seen because of being direct-injection, it’s hidden down below.

The engine drives all four wheels though a very sophisticated yet simple all-wheel drive system that can transfer up to 70% of its torque to the rear axle. The rear differential itself can also vector that torque to a single wheel if necessary, and routinely sends power to the outside wheels during aggressive cornering.

Servicing the Ford Focus RS in spite of its inherent complexity is pretty straight forward. The air filter box is right up front in plain sight and is relatively easy to get into. The battery is right behind that, the main fuse block to to the right.

The brake fluid is the one item you may want to use a long stem funnel to top off as it is buried back under the ledge just a little.

The oil filler cap and dipstick are on top of the engine in plain sight even with the engine cover off. Coolant can be found on the passenger side over the wheel and the windshield washer fluid just ahead of it up front.

Other notable details are the cast composite plastic radiator support to save weight, an element actually pretty commonplace with cars now. Under the hood is also a pretty healthy sound deadening pad to keep the less desirable noises out.

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About the author

Sam Haymart

Smoker of fine tires, eater of natural foods, connoisseur of aromatic leathers, and pusher of limits. Editor at TheMustangNews.com and host at TestDriven.TV. Twitter - Facebook - Google+