Torque vectoring, or torque vectoring control, is a term that you might come across if you’ve visited some of the Focus ST forums on the web. While many view this system as a great benefit, other enthusiasts often bring up this Ford technology in a negative way, bemoaning the fact that it is used a more cost-effective stand-in for the limited-slip differential that they really want for the Focus ST. Not even the newly redesigned 2019 Focus ST comes with an LSD. Ford did finally add one to the 2018 Focus RS, but that was the final model year and only 1,000 were made.
Despite this oft-complained-about omission, it’s hard to complain about the handling prowess of the FWD Focus ST (and its smaller Fiesta ST sibling). Ford spent a lot of time tuning the software and suspension of the vehicle to achieve a fantastic calibration, with sharp handling that is flat and direct through curves.
What Is Ford Torque Vectoring Control?
Ford’s torque vectoring control system helps to improve handling and traction during turns by using the vehicle’s brakes to control the spin rate of a given wheel, effectively mimicking a limited-slip differential. The primary purpose is to improve handling, reduce understeer, and allow for faster speeds through corners.
Ford describes their brake torque vectoring system by using the analogy of a skier going down the slopes, using their outside ski to more effectively turn left or right. In your car, the overall effect of Ford’s system is similar. It applies small amounts of brake pressure to the inside front wheel during a turn, bringing its rotation rate closer to that of the outside wheel. This sends more torque to the outside wheel, allowing for better grip. Ford notes that these brake applications are “imperceptible,” and you almost certainly won’t be able to feel them even in spirited driving.
When wheel slip is detected, braking is applied to the inside wheel, reducing understeer and improving handling.
While we’re mostly talking about the performance aspects of torque vectoring control in relation to the Focus ST, this system has been present on many other non-performance Ford vehicles, from the Fusion to the Explorer. Though the overall process is effective, there are some differences in performance versus a true limited-slip differential.
Despite similar naming and mimicking the general process, it’s important to note that Ford’s system is different than the torque vectoring limited-slip differentials used by other manufacturers, such as Lexus. Instead of using clutch plates, only the brakes are used. This leads to a few downsides compared to a mechanical limited-slip differential, though most drivers are unlikely to notice them in virtually all driving conditions.
Torque Vectoring Control vs Limited Slip Differential
A limited-slip differential, or LSD, allows the driven wheels of a car to spin at different speeds. By transferring power towards the wheel that has more traction in a given situation, overall control and handling are improved. This is especially important for sports cars and off-road vehicles. For most drivers in most driving conditions, a torque vectoring control system will provide similar enough real-world effects to a limited-slip differential. But on a track, the differences will become more pronounced. One of the primary weaknesses of a torque vectoring system is that it uses the car’s brakes to control wheel spin.
This means that, on the autocross course or race track, there are some downsides to not having a limited-slip differential. Most notably, the extra use of the brakes can cause heat and brake fade that would otherwise not occur.
So why didn’t Ford include a mechanical LSD option from the factory? As is often the answer to questions like this in the automotive industry, the answer is “money.” The additional design and manufacturing costs would be much more expensive than this software solution. Plus, the Focus ST also achieves some weight savings by not having one. For the vast majority of situations, Ford’s torque vectoring control system does an admirable job of providing excellent handling in a FWD car.
Limited Slip Differential Options for the Focus ST
If you’ve decided that you want the additional handling prowess and track capability offered by a mechanical limited-slip differential, there are a good number of options. This is a fairly popular mod within the enthusiast community, and you’ll be able to find a differential that works well for your car whether it’s a daily driver or a track-dedicated racer. One option that comes highly recommended is the Quaife-style differential offered by Mountune. It’s well-reviewed, and importantly, approved by Ford. This means that you can have it installed by a Ford-certified service center and it will not break your factory warranty. If you’re ready to or already have installed aftermarket parts that are not under warranty, you have even more options for an LSD. Most will run you about $1,000, not including cost of labor. Despite the steep price, many Focus ST enthusiasts (or at least those that race on the weekends) see it as a necessary upgrade.
Whether or not you’re looking to change the handling characteristics of your hot hatch, you can check out our selection of Focus ST parts to find all of the performance and style upgrades you want for your ride.
Sources: Ford | Lexus
Image Credit: Ford