From Guitars to Supercars

Posted by John Mellberg August 06, 2021

From Guitars to Supercars

Swedish artisan and car builder, Ulf Bolumlid started out producing custom guitars. However, in the 1980s, he pursued his longtime dream of building cars. In 1992, his studio "Designs by Ulf" released their first model, the "Mania Spyder", which was sold as a kit car. After selling almost 50 units, Ulf began work on a more ambitious design, a coupe inspired by Le Mans prototypes and early hypercars of the day.

The machine would be called "Sensor GTR" and was inspired by cars like the Bugatti EB110 and McLaren F1. The car was to be built on a triangulated steel spaceframe, with independent suspension, and bodywork made of carbon-fiber or fiberglass. The chassis was designed to accommodate a range of motors from four to twelve cylinders with up to 1,000 horsepower. One of Bolumlid's most important goals was to achieve the lowest weight possible in the Sensor's construction. The Sensor was estimated to have weighed 750 kilograms in its lightest form.

Ulf Bolumlid's Sensor GTR

In standard configuration, the car was intended to use a V-8 with a displacement of 4.5 liters, rated for 450 horsepower, and more than 500Nm of torque. The engine would be mated to a Porsche 5-speed transmission, sending power to the 18-inch BBS rear wheels with Bridgestone Potenza tires. Sprints from 0-60mph were expected in less than four seconds with a top speed around 190mph.

In addition to the street version, the Sensor was also slated to be offered as a spartan track racer, called the "Superlight". The planned price of the base model started at $150,000, in turn-key form. However, there were no takers and Design by Ulf, which was part of the United Design Group, ceased operations around 2005. Two full size models and three bodyshells were made but the prototype was never completed.

Sensor GTR, design mock-up

However, this would not be the end of the story for the Sensor GTR. In 2016, one of the original bodyshells produced by Ulf was acquired by fellow Swede Per Ajdén with the intent of producing a fully realized car. Ajdén proceeded to 3D Scan the body, design a CAD modeled of the chassis and drivetrain, as well as interior and overall packaging.

The tubular chassis was laser cut and welded up from the CAD data. Its suspension consists of a double wishbone setup in front, with coil-overs at the rear, and the brakes were a combination of Wilwood and Audi A4 components. Motivation comes from a mid-rear mounted Volvo T5 motor, making 344bhp.

Sensor GTR, built by Per Ajdén

Ajdén's Sensor was fabricated almost entirely by himself, with assistance from his brother, in his own garage. Their work included everything from badging and trim, to a custom door operating mechanism not unlike Koenigsegg's cars employ. A vast majority of the cars parts were either scratch-built or heavily customized from OEM items. However, they did contract the paint-work out to a local shop.

The Sensor was completed in 2018. It is a remarkable accomplishment and a tribute to Ulf's original vision. Ajdén's craftsmanship and attention to detail in the build is truly impressive.

Ulf would go on to work with Koenigsegg, fabricating bodies for their initial prototype vehicles, and eventually retire. Ajdén continues to build cars, his latest being a Ford RS2000 rally car replica that is currently in progress.

Sources:
AutoGen Poland
Per Ajdén's Sensor on Instagram

Build Diary on YouTube