Welcome to Modgarage, a website dedicated to the world's first supercharged Alpina Roadster S. A project that required extreme amounts of patience, but also led to new friendships, amazing experiences and ultimately a very satisfying and truly unique result. From picking up the car at a German dealer in 2006 to stripping and rebuilding it in 2007 and 2008, getting it supercharged in Norway and attending the epic Petrolhead Nirvana Alpine Tour: it's all been an unbelievable and unforgettable experience.
The story began in April 2006, when I was looking into buying a fun car to take on weekend trips. After considering several options, I decided to focus on the Alpina Roadster S as I liked the Z4 body style and the typical Alpina refinements to the exterior, interior and engine. At the time, a mildly used Roadster S was available at ¤ 30K (Dutch price) less than a brand new Z4M Roadster while offering roughly the same level of performance. I had a memorable drive up and down to Nuremberg, Germany, to view a sterling grey Roadster S and picked up the car the next week on April 28th, 2006. With just 6000 kilometers on the odometer it was like brand new. In the summer of 2006 I took it out on a holiday to Norway, unknowing the car would later return to the Nordic countries to receive a massive power upgrade. The car remained mostly untouched during 2006 with the only mods an iPod interface, Helene Performance air filter and a Strong Strut strut tower brace.
2007 started off with an amazing London Tunnel Run, which I attended with some of my mates from Driving-fun.com. A few days after returning home my LSD with reduced final drive ratio arrived from Drexler Motorsport in Germany, marking the first serious performance upgrade for the car. March ended on a down note after kissing a tree, damaging the left rear suspension, wheels and body work. At this time I was already planning a massive round of modifications. In early 2007 the car had visited Reiger Suspension to measure the suspension mounting points and to corner weight the car. Other mods in the planning were a big brake kit and a quad pipe exhaust. During the process, the scope of the project grew larger and shifted towards the goal of building the ultimate street driven Z4. In the end, the car received a complete rebuild with a new suspension, new brakes, modified exhaust, racing seats, facelifted light units and a full body repaint, all using the best possible components.
Part of the inspiration for the project came from the classic Alpina cars of the seventies and eighties, when Alpina was succesfully competing in touring car championships across Europe. In the past two decades, Alpina has gradually moved its focus to luxury automobiles with sensible levels of performance. The early Alpina's were born on the track. They were light and agile and were less of a compromise between performance and luxury. In the eighties, Alpina's foray into turbocharging brought us legendary cars such as the B7S Turbo Coupe and the B10 Bi-turbo, a car that was the fastest saloon of its time and enjoys cult status today.
A few years ago, rumours arised on German Alpina boards about the development of a 370HP supercharged Roadster S. The car never made it into production, possibly because Alpina couldn't meet emission regulations or BMW wouldn't allow Alpina to compete with the Z4M. Since Alpina is a shareholder in supercharger manufacturer ASA, it is far from unlikely that the company made attempts to supercharge the S52B32-based engine used in the Roadster S. With my project, I wanted to make this rumoured supercharged Roadster S a reality and I strived to recapture the spirit of the race-bred Alpina cars of the early days.
After completing the first stage of the project in July of 2008, the car was booked into ESS Tuning in Norway for a custom supercharger conversion. ESS Tuning is the number one BMW supercharging specialist in Europe. The twinscrew supercharger kits for the M52 and M54 engines have been hugely popular with the E46 crowd. Thanks to the close family ties between the S52B32-based Alpina engine and the M52 series, the ESS twinscrew charger could be fitted to the Alpina engine with minor physical modifications. I drove the car from the Netherlands to Norway in the weekend of October 6th, 2008, travelling 500 kilometers through Germany in less than three and a half hours. After dropping off the car at ESS' headquarters in the rural countryside of the Aremark municipality in south-east Norway, I took the flight from Oslo to Amsterdam.
Six weeks later, the conversion was ready. I invited my friend and fellow Z4 driver Tom Antonis to accompany me on the trip to Norway and to help me out shooting a video on location in Norway. Since it would be expensive and impractical to move around the video equipment by plane and rental car, I decided to take my Alpina B10 3.2 Touring on a round trip to Norway. Loaded with video gear, we left on Thursday November 13th and picked up the car the next day in Aremark. We had a great afternoon with Asbjorn and Hans, who showed us around the ESS workshop. Asbjorn took us on a test drive in a supercharged 520i with beta stage software and we got to learn some insights about the art of DME tuning. We used Friday evening and Saturday to shoot the video. With a crew of two amateurs our resources and capabilities were limited, but given the circumstances I can be satisfied with the result.
On the way back home there were plenty of opportunities to play with the power of the supercharger on the empty motorways in Sweden and Germany. The performance of the supercharged engine was nothing short of stellar. Everytime I pressed the throttle, Tom disappeared in the rear view mirror within a matter of seconds, even while he was pushing hard in the 260HP B10 3.2. It was like using a translocator in a video game. The ESS supercharger preserved much of the character of the Alpina engine. The engine still shakes and vibrates waking up from a cold start, giving it real character as opposed to today's perfectly polished BMW engines. Once warmed up, driveability is very good. The supercharger allows the engine to breath much better at high engine revolutions, increasing the point of maximum power from 6300 to 7200 rpm. The engine is perfectly suited for low rpm cruising, however, if you want to extract maximum performance you still have to push hard and stay focused.
I used most of my free time in the next year to edit the video footage, develop this website and write content for it. The last big modification was added to the car in February 2009, when I had angel eyes done by Tekarbon in San Francisco. I had a truly epic experience in the summer of 2009 when I joined the Petrolhead Nirvana Alpine Tour, a 5000 kilometer exploration of the best driving roads in the Alpine region of France, Germany, Italy and Switzerland. The tour was somewhat overshadowed by the fact that the French police took away my driving lincense on the second day. On the bright side, it helped to build a reputation . The Roadster S Supercharged has been running fine with the exception of a broken alternator, a cracked weld joint in the exhaust header and some annoying electrical issues that are probably related to the seat and light upgrades.
I hope the project can be a source of inspiration for all mod fanatics and Z4 owners. If you have comments or questions, please post them on the website or contact me at femme at modgarage.net.
|Engine configuration||Inline-6, Supercharged|
|Supercharger type||Twin screw|
|Final drive ratio||3.46 :1|
|Front brake discs||380 mm, Drilled|
|Front brake calipers||6-piston, Aluminum|
|Rear brake discs||294 mm, Drilled|
|Unladen weight||1280 kg|
|Power||445 hp @ 7200 rpm|
|Top speed||275 km/h|
|0-100km/h acceleration||4.2 s|
|Torque||484 Nm @ 4500 rpm|