A dream that started inside a home garage has transformed into one of Australia’s most extreme road-legal performance cars. Built by former KTM racing driver Jeff David, the Quantum GP700 is a lightweight hypercar that combines Formula 1 inspired engineering, advanced aerodynamics, and an engine capable of delivering a power-to-weight ratio beyond 1 horsepower per kilogram.
The project was born from frustration. After purchasing an Ariel Atom in 2005, Jeff David discovered that the car’s performance potential was limited by its handling characteristics, especially during aggressive cornering. Instead of accepting the limitations, he decided to redesign the concept from the ground up.
Using advanced measurement tools and telemetry equipment borrowed from a contact at the Formula 1 team McLaren, David analyzed suspension loads and aerodynamic behavior through strain gauge testing and MoTeC data logging. The results convinced him that the vehicle needed a complete engineering transformation.
What began as a modification project eventually became a clean-sheet hypercar design created using SolidWorks CAD software.
A Twin-Supercharged Monster with a Honda Heart
At the center of the Quantum GP700 is a heavily modified Honda K-Series engine, combining components from several legendary Honda powerplants. The engine uses a CR-V block, Type R cylinder head, and an F22C crankshaft from the Honda S2000.
With a custom twin-supercharger system, the compact four-cylinder engine produces an astonishing 800 horsepower.
Despite its extreme output, the Quantum GP700 weighs only 748 kilograms, giving it a power-to-weight ratio that exceeds many modern supercars and even approaches the territory of race cars.
Quantum GP700 Technical Specifications
| Category | Specification |
|---|---|
| Engine | Custom Honda K-Series |
| Engine Components | CR-V block, Type R head, F22C S2000 crankshaft |
| Induction System | Twin Supercharger |
| Maximum Power | 800 hp |
| Wet Weight | 748 kg |
| Power-to-Weight Ratio | More than 1 hp/kg |
| 0–100 km/h | 2.6 seconds |
| 0–160 km/h | 4.4 seconds |
| Transmission | 6-speed air-shifted Holinger gearbox |
Suspension Technology Inspired by Racing
David’s decades of experience developing suspension systems for endurance desert racing, including the famous Finke Desert Race, played a major role in the Quantum GP700’s chassis development.
The custom suspension system was engineered to handle extreme lateral forces during high-speed cornering while maintaining enough compliance for everyday road use.
Unlike many track-focused machines that sacrifice comfort completely, the Quantum GP700 was designed to deliver race car feedback without becoming impossible to drive on public roads.
Carbon Fiber and Kevlar Construction
The bodywork of the GP700 features lightweight composite materials combining carbon fiber with ballistic-grade Kevlar reinforcement.
This construction provides exceptional strength while keeping weight extremely low. The material combination also helps the body withstand high aerodynamic loads generated at high speeds.
A Garage-Built Engineering Masterpiece
The Quantum GP700 represents a rare achievement in the automotive world: a hypercar created outside a major manufacturer, without the backing of a global engineering department.
After thousands of hours of development and hundreds of thousands of dollars invested into components and testing, Jeff David proved that world-class automotive innovation does not always come from a factory or a corporate research center.
Sometimes, it starts with a vision, a set of tools, and a garage.
What do you think? Could a home built hypercar like the Quantum GP700 compete with today’s factory supercars? Share your thoughts in the comments.
Adhe is part of the 88 Eight Box Editorial Team, covering JDM culture, motorsport, automotive technology, and industry news. The team focuses on delivering original automotive stories, reviews, and insights for enthusiasts worldwide.
