Homologation faceoff: BMW 3.0 CSL vs. Porsche 911 RS 2.7

Photography by Dirk de Jager unless otherwise credited

We’re in the Hockenheim pit lane, early in 1972. Porsche’s freshly appointed company boss, Ernst Fuhrmann, is less than amused.

Even though the Porsche isn’t running in the same class as the faster BMW and Ford coupes, the image of the 911 being beaten by such lesser gods is too much to take in. Fuhrmann demands an explanation: Why are these BMWs and Fords so much faster than our car?

Meanwhile, for BMW, the key question is this: What will beat the Ford Capris in the day’s Group 2 competition? A plan is concocted to create a substantially lighter and more powerful CS: the CSL, with the L standing for lightweight.

This is the story of two icons of the early ’70s, each built out of a necessity to create the best possible race cars. Both became automotive legends.

Building a Batmobile

Photography Credit: Courtesy BMW

The quest to build a faster BMW brings us to a former Porsche factory driver, Jochen Neerpasch. It was Neerpasch who, in his next job as Ford’s competition boss, initiated the first homologation special Capris that would steamroll the opposition.

BMW’s first answer to the race-ready Capris, upgrading its CS coupe with a six-cylinder engine, initially fell short. Racing the BMW coupes was left to private teams like Alpina and Schnitzer, with varying degrees of factory support and success.

A more focused effort was required if the crew from Munich wanted to wrestle away the laurels from the Cologne-based Capris. And at the same time, BMW worked to lure Jochen Neerpasch away from Ford.

At the Geneva International Motor Show in 1971, BMW unveiled that updated take on its coupe, the 3.0 CSL. In September of the following year, the first production car was ready.

The new variant wasn’t just a little faster. It simply moved the goalposts. The original, four-cylinder CS coupe made its debut in 1965 with a 100-horsepower, 2-liter, four-cylinder engine. Once fuel-injected, output from the 3.0-liter inline-six found in the new car reached 200 horsepower.

Plus, the 3.0 CSL weighed nearly 440 pounds less than the standard car–about 2550 pounds total–as aluminum panels replaced steel for the doors, hood and trunk. The front bumper was simply left off, while the rear bumper was changed to a plastic part. Seats and trim were made lighter as well, while plastic side windows were fitted.

Then there was the Batmobile, its nickname coming from the 188 examples homologated as an ultimate version of the CSL. It received an optional aero package comprising a lower chin spoiler at the front, fins on both sides of the hood, and a roof airfoil that guided air toward the massive rear wing.

Not only did the aero package reduce drag by 16%, according to BMW, but the wing construction added more than 65 pounds of downforce at speed, forcing BMW to reinforce the trunk lid.

In the first generation of Batmobiles–those offered in 1973–the wing consists of two uprights. For the final Batmobiles–cars built in 1974 and 1975–a third support was added in the middle. The wing was outlawed for street use in Germany, so it was delivered loose in the trunk.

The CSL paved the way for an even lighter race version that, at a little more than 2200 pounds, sat closer to the Capri’s race weight. The result of this work: In 1973, the first year that BMW was allowed to run the CSL, the European touring car title went back to Munich. BMW would hold the championship through 1979, four years after stopping 3.0 CSL production.

Porsche Forges Its Hero Car

Photography Credit: Courtesy Porsche

Meanwhile, over at Zuffenhausen, Porsche was facing some new realities. When Fuhrmann vented his anger over the defeat of the 911 at Hockenheim, more was playing in his mind than his spur-of-the-moment comments.

Fuhrmann, father of the quad-cam, vertical-shaft engine found in the race-ready 356 Carrera, had just taken the reins at the company from Ferry Porsche. By 1971, Ferry Porsche could no longer stand the internal family feuds that divided the sports car company he’d founded in 1947.

The integration of the Porsche and Piëch children in what was until then a fully family-owned company proved troublesome–to the point that Ferry Porsche withdrew the family members and himself from daily management positions. His nephew Ferdinand Piëch, the brains behind the 917, left the company altogether in 1971.

So by early 1972, Fuhrmann was running the company. From a racing standpoint, it was becoming clear that the 917 would fall victim to changing sports car regulations. The days of the closed-cockpit 917 prototype were numbered, so Fuhrmann wanted Porsche’s racing department to stick closer to the company’s road car offerings for the future.

This was not the brand’s first attempt at a competition-bred version of its iconic 911. In fact, Ferdinand Piëch himself had laid out the foundations for a lightweight 911 with the 911 R in 1967, only to be rebuked by the sales department and, more importantly, by his uncle Ferry Porsche.

When Fuhrmann asked company engineers Norbert Singer and Wolfgang Berger how they could improve the performance of the 911, their answer was very much in line with what Piëch had done five years earlier: Make it lighter and handle better. A special series of road cars would be required for Porsche to homologate a lightweight 911 for Group 4 competition.

Again, sales and marketing were sputtering, deeming such a specialized car impossible to sell. But this time, the company boss just said to do it already. It is testimony to Porsche’s ability to shift quicker than its competitors that just a couple of months later, at the Paris Motor Show in October 1972, Porsche presented the 911 Carrera RS 2.7 to the world.

It arrived hot on the heels of BMW’s lightweight CSL and cost only a bit more to buy. The BMW debuted at close to 32,000 deutsche marks, where the RS 2.7 cost 33,000 deutsche marks–close to $60,000 in today’s U.S. dollars.

Like BMW, Porsche’s formula included more power. Enlarging the 2.4-liter flat-six to 2.7 liters upped power from 190 to 210 horsepower. The new car could reach 149 mph and hit 60 mph in 5.6 seconds.

Stiffer Bilstein dampers, forged aluminum suspension components and reinforced rear control arms improved cornering capabilities. At the rear, a plastic engine cover with integrated ducktail spoiler added downforce; at the front, a chin spoiler did the same.

Porsche offered two different street versions. In the more luxurious Touring trim, the RS 2.7 weighed the same as the 911S at not quite 2400 pounds.

However, 200 lightweight versions shed another 220 or so pounds by dropping anything deemed unnecessary–things like the clock, the rear seats, the sound-deadening material. The interior door handles were replaced with simple leather straps.

The famous Carrera lettering was added to increase sales potential for what was still deemed an impossible-to-sell product. But Porsche needn’t have worried: Within weeks after its public debut, the production run needed for homologation–500 cars–was sold out. Fuhrmann kept production going, however, selling nearly triple that number during the model’s 1973 production run.

The street version allowed Porsche to unveil its 911 RSR in 1973, with Hurley Haywood and Peter Gregg taking one to first overall at that year’s Daytona 24 Hours. Another legend had been released.

Selling in the Stratosphere

The initial fears within Porsche’s sales department were not unfounded. Some now-legendary homologation specials were hard to sell in their days.

It’s hard to imagine today, for example, but Lancia once had difficulty finding buyers for its Stratos HF Stradale. Likewise, the original Cobra wasn’t initially a hot seller.

Despite a goal of selling 500 copies of the RS 2.7, Porsche found buyers for 1580 cars. BMW sold 1265 examples of the 3.0 CSL, with just 188 Batmobiles.

With sporting success and those limited numbers, however, comes mythical status.

Both have become poster cars, icons of ’70s car culture, and both were gifted with a rear spoiler so specific that one can identify the model even without the machine present below.

Apples and Tangerine Oranges

The differences in straight-line speed come down to the BMW’s four-speed gearbox and its greater weight. And in the twisties, it’s doubtful that the Batmobile can mount a real challenge to the RS. It will never be far off, but it doesn’t feel connected to the driver in quite the same way.

The BMW, however, offers superior brakes: better feel and stronger stopping power. And what the Batmobile really does is offer a fast car–fast enough, let’s say–while remaining luxurious. Where Porsche has very much focused on extracting maximum performance from the RS, BMW has retained much of the core of the CS coupe in its high-performance variant.

Forced to pick a winner, we’d have to give the nod to the Porsche as the purer driving machine. Yet we’d have to take a deep bow all the same to the Batmobile, purveyor of big power with a velvet touch.

No losers here.

Behind the Wheel: BMW 3.0 CSL Batmobile

The BMW 3.0 CSL may be known for its spoiler, but our car here didn’t wear one for a long time. Its first owner lived in Switzerland, where government regulations forbade it.

“The spoiler was still wrapped in the plastic it was delivered with when I bought it from the second owner in 2016,” notes the car’s current Belgian caretaker.

Like the 166 other Batmobiles produced, this one wears Polaris metallic gray in combination with the BMW Motorsport graphics, a no-cost option.

This car looks and feels brand-new. With a little more than 66,000 kilometers appearing on the clock–a tick more than 41,000 miles–it’s had just the one respray. The one big upgrade: a set of Eibach springs fitted in 1987.

As you step in, the first thing you notice is the luxurious environment. There is wood everywhere, a lot of light cheers up the cabin, and the Scheel seats look like they’re clad in corduroy. Yet the moment your bum hits that thick-walled sport seat, you feel your hips being fully enveloped.

This is the moment you realize there is more to this BMW than just the add-on spoilers. This is serious.

At slow speeds, the non-assisted steering makes you wonder about the lightweight credentials, especially compared to the 911, which has hardly any weight in the nose. But once the speeds rise, the Batmobile’s steering lightens up nicely.

Compared to the five-speed gearbox in the Porsche, the BMW has to make do with just four forward gears. Yet, both gearboxes have the same quality feel, leading to precise gear shifts.

Being bigger, the BMW doesn’t transition as sharply as the Porsche, and there’s a bit more body roll. But the BMW compensates through the engine.

Perhaps because the Porsche soundtrack is so familiar, the deep drum of the BMW’s inline-six at low speeds feels even more impressive. The Munich powerplant plays more registers, from the deep bellow to a strong raspy tune at high revs, and with some notes you’d find in the M1 as well. It does not rev as high nor as freely as the RS, but the BMW feels every inch as potent as the Porsche.

The first time you look in the mirror, the view with that big spoiler splitting the landscape gives you goosebumps–especially when a Tangerine Orange 911 RS 2.7, one of 126 in this color, is trying to work its way inside.

Behind the Wheel: Porsche 911 RS Touring

The Porsche 911 looks tiny compared to the CSL, as it’s nearly 2 feet shorter. The Porsche cabin doesn’t feel nearly as airy, either, yet it does offer an intimacy the CSL does without.

This RS, a 1973 Touring model delivered new in Switzerland, is wonderfully well preserved, too. It looks like it left the showroom just yesterday, and all remains fully original. The engine has never been opened as the car has covered only 44,000 kilometers–not quite 27,500 miles.

The car lives with its second owner, and he loves to tell the story about a particular mountain drive during an old-timer rally. “We had parked and suddenly a man of a certain age walks up to me and says, with a German accent, ‘What a beautiful car you have there.’ With a smile he added, ‘It is, in fact, my old car you are driving. I am glad to see you as well bring her to these roads she knows so well.’ We talked a bit more. The man, in fact, used to be the CEO of a well-known listed company on the Swiss stock exchange.”

This car has never been raced, never been put on the concours field. Yet it’s always been loved and driven with great care. An anonymous life.

It is here the RS 2.7 differs the most from any regular 911: The RS will always be special. The engine is a bit more present, not only through sound but also in the smell. A sweet scent of warm oil gently penetrates the cabin when the engine warms up.

The combination of the gentle drone from the air-cooled flat-six and the delicate whine of the five-speed transmission creates a soundtrack that soothes your brain better than any favorite coffeehouse playlist on Spotify. Driving the RS at slow speeds is already a very satisfying experience–even if the shifter throws are long, they’re precise.

Compared to the Batmobile, the Porsche’s ride is firm without becoming uncomfortable. That firmness pays off the minute you begin exploring the extra potential in the RS. The tachometer lets you play a bit more–up to 7200 rpm if desired.

At a little more than 3000 rpm, the 2.7 becomes racier, changing in character. It’s all well treating this as a normal road car, pleasant enough as that is, but the real magic happens as soon as you start digging a bit deeper. The long throttle pedal means you need to press on a bit more with your right effort. The engine responds with a deeper growl, and as the revs rise, the hair on your arms starts to stand up. The push is there, but don’t expect to be overwhelmed by the engine in a straight line.

When the cornering starts, however, the RS is still able to feel almighty quick and nimbler than most modern sports cars. The brakes demand a bit of care, but if you have the nose tucked down before the corner, the RS has an incredible ability to switch sides–the benefit of not having an engine at the front, of course.

That same rear-engine layout also delivers supreme acceleration through the corners, where the steering becomes light without ever losing touch with what is happening. Driving a RS 2.7 should be on any driving enthusiast’s to-do list.

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