Jekyll and Hyde: 1973 BMW 3.0 CS

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Some people like the look, feel and smell of a new car—things just work as intended and there are usually few, if any excuses. On the other hand, some people can’t stand the bland sameness that most new cars exude. However, some folks like the look and feel of a classic car yet want the performance and drivability of a new one. This is a tall order.

Sure, engines can be rebuilt, fuel injection added, and interior appointments upgraded, but when it is all said and done, classic cars were built in different times using different materials and following different prerogatives. The ultra-stiff, computer-designed chassis and whisper-quiet door seals of today are the product of much computer simulation and wind tunnel testing. The near-flawless ergonomics and drivetrain smoothness found in practically every modern car, from the most basic Kia to the best Mercedes-Benz, is nearly impossible to replicate in a 30- or 40-year-old car.

There are those who try to make modern perfection out of the old, and one engineer/tuner in Northern California seems to have met that goal. He also added an extra dash of performance, and in the process has built something a bit special.

Passion for the Marque

Bill Watson is the proprietor of Road Rockets, a BMW tuning shop located at Infineon Raceway in Sonoma, Calif. He is a pretty passionate guy—some could even say that he is absolutely obsessed, possessed and focused on building a better classic BMW. Bill has two specialties: the old BMW CS coupes from the early ’70s for the street, and the brand’s 2002 for the track. We sampled his work on the beautiful driving roads in and around Sonoma while attending this year’s HMSA Wine Country Classic. To say that the Road Rocket CS coupe is stunning would be an understatement. Through the use of Electromotive Tec3 engine management and ignition components plus Bilstein, Ground Control and Suspension Techniques suspension parts combined with proprietary components, Bill has designed and assembled one of the most updated classic BMWs we have ever driven. The secret to success in such an endeavor is tuning and sorting, as some 300 hours alone have gone into that part of the project.

What’s a BMW CS?

Introduced in the mid-’60s as the funky-looking 2.0-liter 2000 C and also available as the 2000 CS, the E9-chassis BMW coupe is a four-passenger, two-door machine. Designed as a personal luxury performance car, these coupes were long on style, but low on back seat room.

Speaking of styling, that funkiness comment refers to the styling of the headlights. Absolutely bug-eyed in appearance, this look was quickly revised for 1968 with the introduction of the 2800 CS. Also new was the 2.8-liter “big” six-cylinder engine that made BMW so famous in the ’70s and ’80s.

By 1971, a 3.0-liter version was introduced, first with carburetors and then in fuel injected form. Production faded out by the mid-’70s when the all-new 6 Series coupe was introduced as a replacement.

All in all, only about 30,000 of these fast, sexy coupes were built, making them seem like quite a collectors’ item today. Oddly enough, during the collector car price explosion of the last five years, early BMW coupes have been largely forgotten, making them a good investment and a wonderful, drivable collector car.

What Makes This One so Special?

This 1973 BMW 3.0 CS, dubbed the Neo-Coupe by its builder, was purchased in Canada by Steve Eggen, a successful businessman and San Francisco resident.

Once the car was in California, Bill went to work, starting with the engine. The first order was to bore the engine to 3.7 liters, a fairly common way to add torque to these engines. The compression ratio was kept to a reasonable 10.1:1 since California is plagued with only 91-octane fuel. Wiseco pistons and Total Seal rings are run for maximum efficiency.

Bill also installed a Schrick camshaft along with Pauter Machine valve spring retainers. A lot of cylinder head and intake manifold work, as well as a seriously cool airbox tailor made by Hamlin Fabrication, top off the engine. In addition, a variety of proprietary thermal processes were applied to many engine components, of varying composition, by Orion Research of Salt Lake City.

The pièce de résistance is the super-trick, fully programmable Electromotive Tec3 fuel injection system. The Tec3 has been coupled with Jenvey throttle bodies, Ford Motorsport fuel injectors, proprietary velocity stacks and K&N filters. This system, tuned with assistance from John Watson and Vic Sias of Sias Tuning, not only has incredible performance but also complete docility and drivability, a rare combo. (Watson also credits Bob Sullivan, Dr. Russ Dutwiler and Wendy Iverson for their help, patience and support on this project.)

The exhaust system uses a Stahl header, HPC coatings and a proprietary Spin Tech system custom fabricated by Ian Gordon Racing. Other details include a JB Racing flywheel and BMW M5 clutch assembly. Power is transmitted through a BMW close-ratio five speed transmission.

The final numbers? Peak horsepower is 320 at 5900 rpm, about a hundred more than stock. Torque is up as well, registering a stump-pulling 313 lb.-ft. at 4500 rpm. Not bad engine figures for a 3000-pound car.

Where Does It End?

Everyone has a different thing. Some like cars of the ’50s, some like the ’60s and some like the supercars of the ’70s and ’80s. One thing is for sure: the style, classic status and performance of the BMW coupes of the early ’70s make them definitely worth a look. And if you, too, are a perfectionist and want to spend some extra time and money on your coupe, or any other race or street BMW for that matter, drop by Infineon Raceway for a little chat. You and your car will thank us later.

Ultimate Driving Machine?

So, how does a BMW coupe drive after it has received some $75,000 and hundreds of hours in work? In a word, sweet.

First, however, you must understand that the CS coupes were no slouches in stock form: They had good power along with the benefit of incredibly gorgeous styling and fully independent suspension. These coupes were the pinnacle of BMW performance at the time.

From the moment you slide into the supportive yet comfortable racing seats and turn the key, you know things are going to be different with this one the instant the normally sedate big six rumbles to life.

As we pulled away from Bill Watson’s shop, sure the exhaust grumbled a bit more than normal and the dogleg box was typically notchy for a BMW, but we quickly realized that this machine was more balanced and refined than most other projects.

The steering is perfectly balanced, the ride firm but not abusive, and the exhaust is noticed, but not offensive. Here is a car that is sorted and tuned to the nth degree.

Once out on the road, as we hit second gear, the M5 clutch pulled up sharply, but with not too much pedal pressure; the BMW limited-slip differential grabbed hold as we squeezed the throttle pedal.

What overcame us was not typical BMW coupe performance, but what appears to be all-out M3 power and handling in a package matched with civility and class not often put together, no matter what the age and country of origin.

The nicely weighted steering, Bridgestone Potenza S-03 Pole Position tires and 16-inch BBS wheels make handling effortless. Thanks to Ground Control anti-roll bars and Bilstein shock absorbers, steady-state cornering is precise. Turn-in is sharp, and transitions are completely controllable with a hint of understeer.

The overall feeling of this car was one of two personalities: Driven easily, this CS was all leather, wood and chrome—a true grand touring classic. But when we got to the twisties and unleashed its split personality, those 320 horsepower reached up and slapped us in the face, begging for more.

This article is from an archival issue of the magazine. Like stories like this? You’ll see every article as soon as it's published, and get access to our full digital archive, by subscribing to Classic Motorsports. Subscribe now.