2003 QUANTUM XTREME

A seriously quick and well-developed Quantum Xtreme, weighing approx. 600kg and producing ~300BHP from a Rotrex-supercharged Ford Duratec engine, managed by a MaxxECU RACE ECU.

A properly engineered lightweight performance car that is road legal and perfectly usable on the road, while benefiting from significant investment to make it highly capable for track use.

🔧 Key Specification

~300 BHP Rotrex Supercharged Ford Duratec

Approx. 600kg → exceptional power-to-weight ratio

MaxxECU RACE management system with bespoke tablet mounting/display

Mazda 6-speed gearbox conversion

Paddle-type performance clutch

Double wishbone, multi-link suspension with inboard coilovers

Team Dynamics motorsport wheels with Toyo R888R tyres

Additional set of 5 alloy wheels with road tyres included

Sabelt multi-point harnesses

Removable Sabelt steering wheel

Fire extinguisher fitted

🛠️ Engine Bay & Fabrication

Bespoke cooling system:

Front-mounted radiator and intercooler

Additional rear-mounted cooling setup

Fabricated alloy pipework and components throughout

Work carried out by JEK Fabrications (motorsport specialists)

Bespoke plenum chamber and custom engine bay fabrication

Braided lines with anodised fittings

High-quality components throughout (including genuine Jubilee clips)

EGT sensors fitted to exhaust manifold

🔊 Exhaust & Setup

Bespoke performance exhaust system

Removable top silencer:

fitted for track noise compliance

removable for a more aggressive setup

🧾 Provenance & Documentation

This car was originally built by the manufacturer and featured in two separate kit car magazines prior to my ownership, which reflects the standard of the original build.

It comes with a comprehensive history file, including:

Original build manual

Large folder of paperwork and invoices

Additional invoices currently being sourced for major components (including supercharger and clutch upgrade)

🧾 Ownership & Build History

Over £15,000 invested (£22,000 total build cost).

I have owned the car for around 8 years, with the majority of development and upgrades carried out approximately 5 years ago. It has been built and improved over time with a clear focus on performance and engineering quality.

🚗 Driving Experience

With ~300BHP in a ~600kg chassis, performance is extremely strong.

Comparable in feel to Caterham/Seven-style cars, but with significantly more power than most.

Raw, lightweight and highly responsive.

🧾 General

Road legal

Fresh MOT

Always garaged (purpose-built OSB-lined garage)

Carbon fibre effect bonnet with heat ventilation

Convertible roof and doors included

Mileage: 12,921 (recorded prior to major upgrade phase)

➕ Additional

Separate 7.5” Sierra Cosworth rear differential available by negotiation

📍 Summary

A very fast and well-specified Quantum Xtreme with extensive upgrades in all key areas — engine, gearbox, suspension, cooling and fabrication — supported by strong history and documentation.

Now only for sale as I have moved into a Porsche 718 Spyder and feel the car would be better suited to someone looking to make full use of its performance potential.

** There is a YouTube video by PVE Engineering, who performed the upgrades, initially he intended to do a series of them but if you search the following within YouTube, you will see it, complete with a rundown of what was done. Please remember that this was only the first stage:

"Quantum Xtreme Duratec Supercharger conversion Episode 1"

All hardware was installed with an intention of mapping to 400 BHP, but this would have been far too much. At 300 BHP, it is already insane **