MGU: Single unit / Zytek

Transmission: Two gears / Sadev

In short: Much carbon fibre and a manual gear selector

With the exception of thermal issues in Malaysia, the Renault Sport-developed powertrain has been utterly dominant so far in the second season. That might not be surprising given rumours that the company has spent its way into the tens of millions of euros in development. The Renault has so much pace in hand that it is hard to see anyone challenging the blue and yellow cars this year.

The powertrain employs a single Zytek-developed motor. That’s a surprise, as Renault works with Magnetti Marelli on its F1 electrical propulsion systems so could have been expected to continue the partnership here. Zytek does have history with top end electric machines, however; the company played a significant part in the development of the 2009 McLaren Mercedes F1 KERS system, widely regarded as the best of the breed in F1’s early hybrid era.

Along with the motor, the cars presumably use a Zytek inverter too; certainly, the first season unit supplied by McLaren Applied Technology isn’t in evidence.

The motor drives the rear wheels through a two speed transmission developed by gearbox specialist Sadev. The first gear is used to get off the line at the start of the race (and possibly for very tight hairpins, such as in Malaysia); the second gear has a much wider working range and is used for the rest of the race, such that the driver effectively needs make no other gear changes once in second.

Although a larger motor is required to allow the virtually single-gear race performance, its weight is offset by extensive use of carbon fibre, reported to form both the motor bellhousing and the gearbox casing. This, too, is a departure from the norm for Renault, which does not use carbon fibre for its F1 gearbox casing.

The motor is mounted transversely in the carbon casing and is inserted from the right hand side. The aluminium cover plate then houses the gears to transfer power to the differential. In this orientation and gear set-up, the powertrain does not lose power through a 90⁰ bevel gear set up as it would with longitudinal motor installations.

In a marked departure from the high-tech paddle shifters ubiquitous in sports cars and single seater racing cars, Renault has installed a manual gear selector on the right-hand side of the cockpit, which we reported last month. It is a short metal lever with a black, round knob and is connected via control rods and cables to the carbon fibre gear casing at the back of the car.

At the gearbox end, the control cable is clearly visible when the rear fairing is removed. The cable pulls on a rocker set-up, which then pulls a rod emerging from the gear casing. This casing houses the two gears, which sit between the motor and the oversized differential ring gear.

While the manual gear selector at first seems overly simplistic and fairly old-fashioned for such a technologically-advanced powertrain, it does offer Renault several advantages: a fast start as well as effectively gear shift-less racing, combining the best of geared and direct drive systems; reduced weight; and a simpler, cheaper assembly that is less likely to go wrong.

How much of Renault’s performance advantage is derived directly from the powertrain hardware and software, rather than lightweight materials and well-designed rear suspension, is hard to say. Either way, with Sebastien Buemi in the form of his life, Renault is going to be very, very difficult to catch this season.

Scarbs is technical editor at Current E. Follow him: @ScarbsF1