Published on February 4th, 2015 | by Daniel Sherman Fernandez0
FWD vs AWD: hot hatchbacks
We’re seeing more and more hot hatchbacks adopt an all-wheel drive (AWD) drivetrain in recent years. Traditionally these models have been front-wheel drive (FWD) by virtue of their packaging and powertrain, but what has pushed manufacturers to develop AWD systems for their hot hatchbacks?
In the pursuit of higher power outputs, it becomes more difficult for an FWD car to put the power to the road without spinning the wheels. In some cases, high torque outputs result in torque steer- an involuntary pull of the steering in one direction or another, unique to FWD cars. There are ways to negate wheelspin, such as using a limited slip differential (LSD), and some cars manage torque steer better than others (such as the Renault Megane RS265), but ultimately these issue become harder to deal with as power outputs rise. In reality, anything more than 250 bhp and 300 Nm of torque becomes quite a handful for an FWD car to handle. Unfortunately, progress dictates that power levels must rise with each successive generation, and so manufacturers have to adapt.
AWD systems have various uses, from the traditional off-roading application, to high performance in low grip situations. We’re looking at the latter case, and in the context of hot-hatchbacks with transverse mounted engines, the AWD systems tend to be front-biased (more power goes to the front wheels more often). The advantage of AWD is that it manages power so that all wheels maintain grip and solid contact with the road. From a general standpoint, an AWD car can apply more power to the road as the power is divided over 4 wheels as opposed to 2. Currently, the Volkswagen Golf 7 R and Mercedes A45 AMG are the only AWD hot-hatchbacks in class, soon to be joined by the Ford Focus RS.
But AWD doesn’t always beat FWD. In the dry, the Volkswagen Scirocco R proved to be a more nimble, agile machine than it’s sister- the Volkswagen Golf 6 R. Despite being FWD, the Scirocco R was more stable under braking and had more neutral handling- whereas the Golf R tended to push a little bit wide with mild understeer. Both of these cars use the same chassis, albeit set up slightly differently and with different weights as well, but with identical power outputs it is a good comparison between FWD and AWD.
Where the Golf R does shine is in low grip situations, such as damp tarmac or on dirt. The Golf R is far superior when delivering the power, negating the wild wheelspin that occurs with FWD cars. While it is easier for the Scirocco R to rotate into a corner, it suffers from a lack of traction on corner exit- which is where the Golf R can rocket out with surprising stability. The same applies to track work, where the Golf R can accelerate harder and earlier out of tight turns without risk of understeer.
So we’re keen to see how Ford sets up the all new Focus RS. Announced with roughly 320 bhp and an AWD system, it should prove to be quite a weapon on both back roads and the track. But whether it can be as agile and nimble as the Fiesta ST is yet to be seen; hopefully Ford engineers will tune the chassis for a more neutral balance and maximize the effectiveness of the AWD system. While the Focus ST remains a 250 hp FWD hot-hatch, the Focus RS may operate on an entirely different level.