Quantum GP700

Quantum GP700

Not exactly what you’d call ‘classically beautiful’, but the results speak for themselves.

There are some things in life that just don’t make sense. Like why certain groups of adults insist on wearing their hats backwards and why the United Kingdom is spoilt for choices when it comes to open top, ‘track cars’. Here are cars with no roof, no windscreen and open wheels, widely available in a country which has areas that see 3000mm of annual rain. One of life’s many mysteries, eh?

Head 15,000 kilometres Southeast however and you have Australia, land of animals that are habitually trying to kill you, convicts and sunburn (especially in the case of the hat-backwards patrol). The market for open top track cars in the land down under is trifling which is odd when you consider it’s often referred to as the ‘wide brown land’ due to its abundance of fine weather. However, there is one company that’s trying to fill that void – Quantum.

Quantum GP700

Not hard to see how the GP700 produces over 2G of cornering force from this angle…serious aero’ and barely legal R-spec tyres.

Quantum’s GP700 is as creatively named as Koenigsegg’s Agera One:1, in that it has 700hp and weighs in at, you guessed it, 700kg. The brainchild of a Melbourne based father and son, Jeff and Andrew David, the GP700 has been a seven year labour of love seeing them design and/or build everything from the Ariel Atom inspired chassis, to its Honda based power-plant. The GP700’s similarities to the British Atom aren’t coincidental, with Quantum’s first foray into ridiculously powered, under-dressed cars starting with a re-engineered Atom.

Not content with the 600hp supercharged Honda motor in their Atom, the Quantum lads added another supercharger to the GP700’s 2.7L four cylinder. The K24 based motor, typically found in US Honda Civics, has had its capacity bumped up from 2.4L thanks to a custom crank, rods and pistons. The new crank is a whopping three kilograms lighter than stock and helps revs reach a monstrous 10,000rpm. The two centrifugal superchargers are set-up to work as a compound supercharging system. This set-up means the superchargers are mounted in series, with one smaller supercharger channeling boost into another larger one, in a bid to reduce lag.

Motec data logging dash strangely teamed with what looks like a Suzuki Hayabusa instrument cluster. Presumably the only set of gauges Quantum could find with a 10,000+rpm rev counter.

Would Sir/Madam like some carbon-fibre with their gauges? Motec data logging dash joins Suzuki Hayabusa sourced analogue cluster for some reason.

Speaking of lag, Quantum has the Holinger supplied sequential gearbox shifting in 0.025 seconds, allowing the GP700 to hit 100km/h from rest in just 2.6 seconds. No lag there either, then. If you want a rough idea what that feels like then you’ll be exerted to more G force launching the GP700 than jumping out of a plane (1G vs. 1.2G).

The car’s handling and braking hasn’t been forgotten either, with years of work modeling geometry and layout using Suspension Analyzer Pro, SolidWorks and Excel spreadsheets. Dutch suspension manufacturer WP provides the position displacement dampers, which are a first for a car. This style of damper is common in motocross bikes, with Jeff David adopting them for the GP700 after 30 years’ experience in valving and tuning motocross suspension before setting up Quantum.

The results speak for themselves, with a claimed 2.5G of cornering force, on street legal R-spec tyres, thanks in part to the suspension tuning and also the GP700’s bodywork that can produce more than 700kg of down force at 280km/h. The Wilwood supplied brakes, low weight and barely road legal tyres produce over 2G of stopping force and should see you stopping the GP700 from it’s top-speed of around 320km/h fairly briskly.

Impressive. But $900,000 worth of impressive? I'll let you be the judge.

Impressive. But $900,000 worth of impressive? I’ll let you be the judge.

There is however, an elephant in the room – the GP700’s price. At $900,000AUD it’s not a small elephant either, it’s the fully-grown matriarch of the herd. While Quantum argues that the price is befitting of the performance, one has to wonder how many people will be willing to fork out the best part a million dollars for a car built in a shed by a man called Jeff. So it seems that while Australia has the weather for roofless, windscreen lacking track cars, they’re not exactly what you’d call accessible. Still, doesn’t explain those people wearing their hats backwards…

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