How We Built A V8 Stealth Beetle

Building a V8-powered Volkswagen Beetle isn’t exactly straightforward, but here at 3L Engineering, we thrive on challenges. Our V8 Stealth Beetle took the iconic “people’s car” and turned it into a high-performance machine, complete with a twin-turbo V8 engine. Here’s how we did it, step by step, and how our creation caught the eye of Top Gear.

1. Starting with the Vision: Why a V8 Beetle?

The classic VW Beetle is one of the most recognizable cars from the 60s through the 80s, known for its distinctive shape and modest 40 horsepower engine. But we wanted to turn that perception upside down, so we set out to create something truly unique: a mid-mounted V8 twin-turbo Beetle. This required more than just an engine swap; we needed a custom-built chassis, new suspension, larger brakes, and a whole lot of ingenuity.

2. Finding the Perfect Donor Car

Our first task was sourcing a suitable Beetle body. Fortunately, our spray painter knew of a well-preserved Beetle that had already undergone some restoration. The car’s original color was also close to what the client had requested, making it the ideal starting point.

Removing the Beetle’s body from its original chassis is surprisingly easy – held on by just 15 to 20 bolts. Once the body was separated, it became clear that extensive modifications were needed. We cut out everything behind the back seats to make room for the V8 and the twin turbo setup, leaving only the shell and fenders. To maintain the car’s structure, we reinforced the body with mild steel supports and made significant alterations to the dashboard.

3. Custom Aluminum Chassis

The heart of the V8 Stealth Beetle is its bespoke aluminum chassis. Made from 5083-grade aluminum (often used in shipbuilding and fuel tankers), the chassis consists of 38 panels that are laser-cut and CNC bent for precision. We then assemble the panels in a custom jig, ensuring a 0.1 mm tolerance fit. It takes about 12 hours to weld the entire chassis, after two days of preparation. The result is a lightweight, rigid frame that can handle the immense power of a mid-mounted V8 engine.

4. Engine and Transmission Choices

For this project, we selected a 4.2L Audi V8 with 40 valves, paired with a six-speed manual transaxle. We sourced the engine components, including a clutch, flywheel, and pressure plate from the UK, while also adding two turbochargers to boost performance. Integrating the twin turbos required modifying the engine’s compression ratio, designing a custom exhaust system, and installing a water-cooled intercooler.

The transaxle ensures that the car’s weight is balanced in the center, enhancing its handling. We also included a chromoly roll cage, giving the car a more aggressive look while providing essential safety features.

5. Test Drives and Fine-Tuning

Once the drivetrain was installed, we test-drove the car without the body to fine-tune performance. This “naked” stage allows us to check for any mechanical issues like oil leaks and adjust the engine’s parameters safely. We then took the car to the dyno, where it reached speeds of 220 km/h in fourth gear at 6,000 RPM during power runs. On the dyno, we could tweak the ECU mapping, optimize the air-fuel mixture, and monitor temperatures without worrying about road conditions.

6. The Final Assembly

After the dyno testing, we began the final assembly. This included fitting the fenders, connecting the lights, installing the Napa leather interior, and securing the glass. The roll cage and other safety components were also finalized. We took our time with the final touches—polishing the car and making sure all the small details were perfect, because as we like to say, “The last 10% is 40% of the work.”

7. A One-of-a-Kind Machine

Every V8 Stealth Beetle is unique, and no two builds are exactly the same. This particular Beetle features the Audi V8 with twin turbos, but we’re already preparing to take on our next challenge: fitting a Chevrolet LS engine into the same platform. Each project presents new opportunities for innovation, from custom chassis design to bespoke exhaust systems.

Why the V8 Stealth Beetle Stands Out

What started as a passion project for bespoke engineering has become a statement in automotive craftsmanship. With the V8 Stealth Beetle, we didn’t just build a car – we created a completely unique driving experience, which is why Top Gear took notice. This Beetle isn’t just about adding more power; it’s about pushing the boundaries of what’s possible with a classic car while maintaining the spirit that made the Beetle iconic in the first place.