Just What Is A Supercar?

One of my earliest articles was an introduction to Supercars. It was a simple introduction that covered the basic aspects of the Supercars championship. This week, I’ll be explaining in greater detail the cars themselves.

Engines
Today all Supercars are powered by a 5.0 litre naturally aspirated V8 engine running on E85 ethanol. Ford, Holden and Nissan each have their own engines, and the engine must match the body. The Ford engine is a Boss 302-derived engine, and the Nissan from the VK56DE. Holden use something called the Holden Motorsport V8. The origins of this engine are unknown, but it’s most likely a small block Chevrolet, although some sources claim it’s a Holden 308. There is also a generic LS-based V8 Supercar engine developed by Craig Hasted, although it’s never been used.

Currently there five engine suppliers. KRE builds Holden engines for Triple 8 and Triple 8 customers, Walkinshaw builds Holden engine for themselves, Garry Rogers Motorsport, Erebus Motorsport and Brad Jones Racing, Prodrive and DJR Team Penske each build their own Ford engines, and Kelly Racing builds Nissan engines with help from Nismo in Japan. From 2014 to 16, Polestar/Cyan Racing built and serviced Volvo B8444S engines in Sweden for GRM. Erebus also built their own AMG M156 V8s from 2014-15.

The engines have a 7,500 rpm rev limit. Engine parity is achieved through cumulative horsepower. Power is measured at 50 rpm intervals between 5,800 and 7,450 rpm. The highest cumulative figure becomes the maximum until all engines have reached that figure and development can then resume. Teams are cagey about how much power their engines produce, but peak power is believed to be around 650hp.

From next year, engine rules will be opened up to anything that complies with the cumulative horsepower figures achieved by the V8s. Triple 8 will run a Cadillac twin turbo V6 in their Commodores at selected rounds, before a full time debut in 2019. Nissan is also considering a move to a twin turbo V6 in 2019.

Transmission
All Supercars run a control six speed Albins ST6 transaxle. Supercars is one of the few professional championships using a sequential shifter and clutch pedal. Paddle shift is under consideration for 2018 in an effort to improve leg protection.

Chassis and Suspension
Supercars run a control chassis designed by Pace Innovations with a carbon kevlar body shell resembling a four door sedan sold in Australia. The bonnet and lights are the only parts taken from the road car. Teams may build their own chassis, or buy one from a third party supplier. All teams build their own chassis or buy them from Triple 8. Pace Innovations supplied some teams with chassis in 2013 but haven’t since. The chassis are Supercars’ intellectual property and are not allowed to be built outside Australia or leave Australia without Supercars’ permission.

A control double wishbone rear suspension setup is used by all cars. Teams are free to design their own front suspension, but it must be a double wishbone design fitting the chassis pickup points. Teams can also choose their own shock absorbers from one of three approved suppliers: Sachs, Supashock and Ohlins. Sachs were previously the dominant supplier, until Prodrive switched to Supashock in 2015 and started winning every race. Walkinshaw, Erebus and DJR Team Penske have since adopted Supashock shock absorbers.

Brakes
The brakes are another control item, supplied by AP Racing. ABS is banned, but brake bias can be adjusted by the driver during the race. Last year Triple 8 adopted a brake bias control mounted close to the steering wheel, allowing their drivers to quickly adjust it between corners. Traditionally teams have used a lever on the floor next to the gear shifter,

Tyres
Dunlop supply control tyres in two compounds. The hard and soft compound tyres used in recent seasons were replaced this year by soft and super soft, with an all new construction for the first time in nearly 20 years. Unlike in Formula 1, teams are not given much choice over when they can use them. The tyres used are dictated by the rules of each event. At some, teams are given an allowance of both and can run them at any time in the race. Other rounds will only use one compound. All drivers qualify on the same compound.

Aerodynamics
Supercars run limited aerodynamic aids consisting of a simple front splitter and rear spoiler. Aerodynamic parity is closely monitored. Aerodynamic testing is conducted in December at the East Sale RAAF base whenever a new model is introduced or a team wants the parity reassessed. Coast down testing is used, despite its inherent inaccuracies and offers of free wind tunnel use from Monash University. This method, and errors in results, both real and alleged, makes aerodynamics a contentious issue among teams and fans.