Ford says 'hello' to real torque vectoring

By Christopher A. Sawyer
The Virtual Driver

(February 9, 2015) It was while touring GKN’s European facilities in 2005 that I first came face-to-face with torque vectoring. During a tour of the production area, one of the executives started bragging to me about the technology’s capabilities, saying that I should find the time to make my way to GKN’s cold weather test facility where I could drive a Mustang fitted with the system.

There, he claimed, I would see how the ability to “fire” the electronically controlled clutch packs on either side of the differential not only gave the Mustang unheard of agility, but helped it to climb the icy, steep grades normally reserved for all-wheel drive vehicles.

Intrigued, I inquired as to the cost, and discovered that the price to the OEM was around $500. Given the normal rule of thumb, that would have meant a cost to the consumer of nearly $1,500, an exorbitant amount. Still, I wanted to see just what this technology could offer, but my schedule would not allow the side trip.

A year later, I had a chance to drive an Audi A6 Avant fitted with a torque vectoring rear differential closer to home. A tight, sinuous track was set up, and I was encouraged to drive the A6 quickly. Despite its all-wheel drive system, the car suffered from grinding understeer on entry to the turns, and momentarily lost traction coming out of them. It was like trying to navigate a cruise ship up a small river.

Engaging the torque vectoring system, which could be altered via laptop by the engineer sitting in the passenger seat, had a marked effect on the Audi wagon’s handling. With just a few keystrokes, the cruise ship became a cabin cruiser. A few more keystrokes, and the cabin cruiser became a sport boat able to pirouette quickly and cleanly around the tightest corners.

To show just how much effect the torque vectoring rear differential had on the A6’s handling, the engineer had me drive the car in a straight line as he engaged first the right, then the left clutch packs. With the steering wheel held straight, the Audi turned first one way, then the other — and quite sharply as a greater right-left torque split was dialed in — without any action on my part. Unfortunately, the cost had not come down much in the interim; it was still to high for most consumers.

Fast forward to 2015, and Ford announces its 2017 Focus RS will come standard with “Ford Performance All-Wheel Drive with Dynamic Torque Vectoring” to give the RS a “new level of capability and driver enjoyment.”

Ford claims this is a proprietary design, but that may depend upon your definition of the word “proprietary.” That’s because the trick rear differential on the RS is being supplied by GKN. Undoubtedly, the tuning of the system is proprietary, as is the packaging. Like the systems chronicled above, the Focus RS can shift 100% of the rear wheel torque (70% of total drive torque) to either wheel, and dynamically vary the side-to-side torque split in milliseconds.

Plus, Ford also is using brake intervention torque vectoring to smooth out the transition. As volumes rise, the cost per unit will begin to drop, and increase the opportunity to use this layout in other vehicles. Thus, rumors of an all-wheel drive Mondeo/Fusion ST may not be too far off the mark, even if there are some within Ford Performance who would like to do a full-blown RS version of the sedan as sort of a poor man’s Audi RS4.

Unfortunately, the rest of the 2017 Focus RS’s all-wheel drive appears to not be as exciting. Though Ford spokespeople were reluctant to do more than generalize about the new Focus RS, they let slip that the all-wheel drive system does not engage unless there is slip between the front and rear axles, which suggests that a viscous coupling center differential is used. The reasons are simple: cost and fuel efficiency.

Adding an electronically controlled clutch pack to the center diff. is possible and would improve performance and handling marginally. However, the difference is not enough to justify the increased cost. Also, not only does a viscous coupling react quickly enough, it is also lighter and improves fuel economy by leaving the rear wheels undriven when traveling in a straight line.

Ford says the Focus RS will generate more than 1g in lateral grip, and controlled oversteer drifts will be possible on the race track. Michelin will supply two types of 235/35R-19 tires, either the Pilot Super Sport RD or the semi-slick Pilot Sport Cup 2. (No fair guessing which gets you over the magic 1g cornering barrier.) In addition, there is a Drive Mode button located on the center console that allows the driver to choose between Street and Track settings; the latter being perfect for those drifts mentioned earlier.

It controls the two-mode switchable dampers, loosens the reins of the electronic stability control system, and alters the settings for the dynamic and brake-intervention torque vectoring systems. Also, steering feel has been improved via front suspension changes. These include shorter front links and a stiffer knuckle design.

Under the hood sits an updated version of the 2.3-liter EcoBoost four that is optional on the Mustang. With EPA certification yet to be completed, Ford is only willing to say that it will produce “more than 315 horsepower, and be mated exclusively to a six-speed manual gearbox.

The cylinder head uses an upgraded alloy and revised head gasket to deal with the greater boost pressure delivered by the new twin-scroll turbocharger and its larger compressor. This suggests the Focus 2.3-liter EcoBoost will produce more than the 134 hp/liter found in the 2015 Mustang. If we assume that the horsepower number goes to 140 hp/liter, that would give the RS just over 320 hp. Is this enough to justify the change in head material and the (rumored) stronger cylinder liners? Maybe not. However, it’s not at all certain that the claims the RS motor produces 150 hp/liter (345 hp) are on the mark.

So let’s split the difference and suggest that Ford engineers will launch the RS with 145 hp/liter, or a little more than 330 hp, and save the higher output claims for a limited-edition RS that will arrive at the end of this generation car's life. Like the RS500 it will be created with the help of Mountune.

The Focus RS will go on sale during calendar year 2016, and include an eight-inch touchscreen and the next generation of Sync. Partial leather Recaro front seats, a flat-bottom steering wheel, alloy pedals and additional gauges above the instrument panel’s center stack also are standard. As we get closer to launch more information will be available, including the cars claimed performance, engine output, fuel economy, the size of the Brembo discs and number of caliper pistons, pricing, production numbers, etc.

We may even get official word about the availability of the car’s Liquid Blue paint (rumored to be offered on all Ford Performance vehicles in the near future).

The Virtual Driver