Racecar Engineering Offroad - Sample Issue by The Chelsea Magazine Company

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WORLD RALLY

How the FIA has improved safety

ODYSSEY 21

Development of the revolutionary chassis

BRUMOS RACING

David Donohue’s Porsche examined

ANDROS TROPHY

Electric rally cars in the European snow

WRC | 2023 ROUNDUP

Stage craft With hybrid development issues persisting, the leading teams in the WRC are now running closer than ever By Lawrence Butcher

he 2023 FIA World Rally Championship saw Toyota’s Kalle Rovanperä build on his record of becoming the youngest champion in the sport’s history in 2022 at the age of 22, and the first of its new hybrid era. He repeated the feat in 2023 and Toyota successfully defended its manufacturers' title. While Toyota dominated, Hyundai made considerable improvements to its i20, turning what looked like a disaster at the beginning of the 2022 season into a winner. Due to the way development works under the WRC regulations, updates must be introduced via the use of ‘jokers’, meaning manufacturers tend to add parts for the next season before the year is out, in order to make best use of their allocation. Jokers can only be added at fixed points in the year, with submissions having to be made on 1 January, 1 April, 1 July and 1 October. Though, as will be covered here, there are ways to circumvent these restrictions.

Toyota’s GR Yaris Rally1, with Kalle Rovenperä behind the wheel, proved dominant over the last two seasons. Pictured here in 2022, the first year the WRC raced with hybrid powertrains

» ‘Quite a lot of the reliability-

type improvements we’ve made have been somewhat statistical. This is not a way of engineering we would prefer to do in other areas of the car’ Tom Fowler, technical director at Toyota

RALLY | RENAULT CLIO RALLY3

The power of 3

As Renault unveils its latest World Rally contender, the future looks promising for the new middle rung of the FIA’s progression pyramid By Lawrence Butcher

he FIA’s Rally2 (the category formerly known as R5) has been a resounding success, with manufacturers such as M-Sport and Skoda selling hundreds, if not thousands, of cars to customers since the cost-capped rule set arrived in 2012. However, at one step down from the top of the current rally pyramid, Rally2 can hardly be described as accessible, with contemporary machines coming in north of €200,000 (approx. $212,000) after tax. A bargain for what they are, but a significant jump from the 2WD vehicles present in the Rally4 class. Since the effective demise of Group N4 (think Evos and Imprezas) there hasn’t been a logical stepping stone into 4WD competition. Enter Rally3, the middle rung of the FIA’s much-vaunted progression pyramid. Rally3 cars are cost capped at just over €100,000 (approx. $106,000), a significant saving over a Rally2, and compared to the few Group N4 cars still available.

» ‘The technical

regulations are quite open, which makes it interesting for us as engineers to work’ Yann Paranthoën, chief engineer and project manager on the Clio Rally3

EXTREME E | THE ROUTE TO HYDROGEN

Ongoing Odyssey How Extreme E’s electric off-roader has evolved, and what’s to come when hydrogen enters the mix By Daniel Lloyd The Spark-built Odyssey 21 is now at the end of its third season of competition, and has been progressively evolving throughout that time

xtreme E is now three seasons into its ambitious journey of taking electric motorsport out of the city, into the wild. Created by Formula E architect, Alejandro Agag, the championship’s aim is to highlight the destructive impacts of climate change by staging short off-road races in affected environments such as Greenland, Senegal and Chile. Stars such as Lewis Hamilton and Nico Rosberg lend their support to entries, while established teams like Andretti Autosport, McLaren and Chip Ganassi Racing compete. Although Extreme E is a spec series where the motor, inverter, battery, chassis, along with a number of other components, are tightly controlled to keep costs down, it hasn’t been exempted from technical evolution.

The Odyssey 21 of today is a tougher, more reliable beast than the Odyssey 21 of three years ago. The developments that have taken place in that time have laid the groundwork for a platform on which Extreme E can test hydrogen fuel cell capabilities ahead of its next big leap. The original racer was publicly unveiled in July 2019, and raced for the first time in the sand dunes of north west Saudi Arabia less than two years later. The inaugural championship consisted of five X-Prix events on four continents. Despite the success of launching a series during the coronavirus pandemic, there were some technical teething issues in the first season. For instance, the suspension package of a three-way adjustable mono damper gave too limited range of movement for the demands of the terrain.

RALLYCROSS | HANSEN PEUGEOT 208 RX1E

Flick of the switch Rallycross switched to electric powertrains in 2022 and, despite a fire at Lydden Hill in July '23, the series remains committed to battery-powered competition By Lawrence Butcher

» ‘We love to run these cars because you know, there’s no smell, no exhaust, it’s not noisy with people setting up their anti-lag systems. Yeah, we like it a lot’

Kenneth Hansen, team principal at Hansen Motorsport 46

allycross (RX) was the ideal candidate for electrification and, as it made the switch at the start of 2022, actually beat Formula E to the count in being the first all-electric series with FIA world championship status. With short duration heats, the need for excessively large, and therefore heavy, battery packs is negated, while the instant torque of an electric powertrain perfectly suits the point and squirt nature of RX and its short course tracks. Teams were given the choice of retro fitting their existing ICE Supercar class machines, or building bespoke cars to the new rules. In the case of Hansen Motorsport, which won the title in 2015, 2019 and 2021 and is headed by founder and principal, Kenneth, himself a 14-times European RX champion, it went the retro fit route. Having previously been the factory effort for Peugeot Sport, Hansen took its successful, ICE-powered 208 RX1, a car under constant development since 2014, and turned it electric.

Pros and cons According to Hansen, speaking at the Lydden Hill, UK, World RX round in July, there are pros and cons to each approach. For his team, it was the financial reality of building a completely new car, and having a well-proven platform to hand that swayed the decision. While those creating RX1e cars from scratch could optimise for the electric powertrain, rule breaks for retro fits could also be exploited. For example, there are lower weight limits on certain suspension parts. Conversely, wheel travel is limited to 250mm (previously in RX1 there was no limit, which remains the case for dedicated RX1e cars). Hansen notes that at tracks such as Lydden Hill, the constraint on wheel travel is not a real issue, but that’s not the case everywhere RX visits. ‘On some tracks, where you have more jumps, harder kerbs, it could be a negative. But we have some positive things with the unsprung weight, which is always something interesting.’ The electric powertrain also provides greater packaging flexibility than the previous ICE. Though the location of the main drivetrain elements is fixed, they take up less space so some of the previous challenges created by the location of engine and transmission are removed. When it comes to weight distribution, the EV drivetrain places the mass in different areas, compared to an ICE car, with a motor both front and rear.

Audi's innovative hybrid uses MGUs from its Formula E racer on each axle, a third electric motor to recharge the battery and also has a 2.0-litre ICE range extender borrowed from the manufacturer's old DTM programme 55