And did any of the German marque’s Coupé Sport Leicht models match the muscular excess of the 1975-6 IMSA machine, built to take on the GTO class of the IMSA Camel GT series?
These were the elite 3.0 CSLs in a long line of victorious E9-shape racing BMWs that had stretched back to the beginning of the decade. The CSL had been the first car chosen for development under the BMW’s performance subsidiary team, and was the logical next level in a touring car arms race that had started in the ’60s with the introduction of a new range of smaller, more compact Neue Klasse saloons.
The CSL had stepped things up in every sense. Its long, raked lines and perfectly pronounced nose that seemed to be reaching forward for even more speed gave it the ultimate look for a ’70s pin-up.
‘Leicht’ mean lightweight, highlighting the use of aluminium doors, boot and bonnet, thinner steel for the body and Perspex replacing the glass windows: these were stripped out specials aimed at the FIA Group 2 touring car rules.
BMW took their E9 coupé and knocked out a series of road-going homologation specials to satisfy production regulations in ’72. As with any homologation dodge, the street cars were purely to tick a box: the rear wing was tucked in the boot when you drove off the forecourt, as it was illegal for the road in most countries.
As the CSL programme kicked in, BMW poached Jochen Neerpasch and Martin Braqungart from Ford’s European racing programme – these two personnel would be the architects of BMW’s future racing success. CSLs went on to win six European Touring Car Championships for BMW between 1973 and 1979, and the car was successful in many national championships, including the DRM in Germany.
The CSL’s development continued year on year in Europe ahead of its eventual assault on the US. In 1973 the original 180hp 3-litre inline-six (a cast-iron block with an alloy head, longitudinally mounted) was increased to 3.2-litres – though the car always remained designated a 3.0 CSL – and then the new 3.5-litre M49 engine was developed for 1974, with DOHC and 24 valves. This was where the fun really started.
The body also continued to buff up, with the fenders getting wider and wider and the splitter more pronounced with each iteration until it reached this ultimate evolution in ’75, with the original narrow body hidden inside a cocoon of add-ons.
A five-speed Getrag gearbox replaced the original four-speed and the suspension was beefed up: the front mounted McPherson struts with Bilstein gas-pressurised shock absorbers and the rear semi-trailing arms with coil springs and Bilstein gas-pressurised telescopic dampers. Power was now up over 400hp and the CSL cleaned up in Europe, with the factory ably supported by the Alpina and AC Schnitzer customer teams.
But then the oil crisis of the mid-’70s led to severe rule changes in Europe that pulled back the previously reasonably open regs, restricting engine power and banning the extreme body kits. As opportunities diminished in Europe for the wide-bodied racers, they opened up across the Atlantic.
With the more powerful engine in place, BMW North America saw the perfect opportunity to use the up-gunned CSL to take on the dominant Porsches in the IMSA GTO class for 1975 and face off against a new level of opponent. Whilst the touring cars withered the GT BMWs prospered, and ushered in a new era of competition for the marque.
The GT-orientated IMSA regulations in the USA allowed BMW’s M squad to work on creating an even more extreme racecar. Further weight was taken out, bringing the base down to around 1,000kg, and the corners inflated yet more.
If it was the Adam West Batmobile before, now it was the Dark Knight. In each corner super-wide fenders were bolted on, with those air formers still running down the sides of the hood, marking the increasingly large difference between street and circuit.
Even then, the fenders barely contained the wide track and enormous racing slicks.
16″x16″ BBS centre-lock split-rim alloys and huge 350/1650-16 Goodyear rubber shrouded the big ventilated discs behind…
…whilst up front 16″x13″ rims and 300/625-16 tyres tried to keep everything pointing in the right direction in the face of the 430hp going through the rear.
The shovel nose was made even more pronounced with a new front air dam, and those blacked-out lights and grill were the perfect complement to the white ‘n’ stripes BMW racing livery.
Unlike the cramped conditions inside a modern GT, the CSL’s cockpit was positively cavernous, with the only obstacle the rollcage’s protective side tube.
Inside, as you’d expect for a car of the time, the switchgear is straightforward: a row of simple buttons controlling ignition, wipers, lights and fuel in the central console, and in front of you central RPM (with 8,500rpm redline) and temp gauges and the three-spoke wheel.
The foot-rest dwarfs the road-car size clutch and brake pedals, and the floor-mounted throttle pedal appears needle thin: delicate controls for such a brute of a car.
With the E9 a true four-seater, the boot full of fuel and the intercoolers and radiators in the fenders, there’s plenty of empty space behind the seats.
The twin exhausts exiting out of the passenger side give the CSL a distinctive sound, popping and crackling when out on track…
…whilst out back is the hydraulic connector for the built-in air jacks.
These weren’t a new technology, but it was still relatively unusual to use them because of the extra weight they inferred.
But in endurance racing every second would count in a pit-stop, so the CSLs were fitted with a full four-point pneumatic system mounted inside the wheelbase. These definitely had seen some action.
Five CSLs were built to race in the USA, and across the two seasons they competed CSLs took seven wins at tracks including Sebring, Laguna Seca, Riverside, Daytona, Lime Rock and Talledega – Hans Stuck took four victories in 1975 alone.
Brumos’ Porsche RSR still took the Camel GT Trophy in 1975, but it proved the CSL was a competitive prospect. In 1976 Peter Gregg and Brian Redman achieved victory in the Daytona 24 Hours against stiff competition from Porsche and Corvette – BMW’s first blue riband victory in North America, and where we had caught up with this, the winning car.
BMW North America still retain ownership of this chassis, after 38 years.
Many other famous drivers had been behind the wheel of the IMSA CSL in period, including Sam Posey, David Hobbs, John Fitzpatrick, Hurley Haywood, Ronnie Peterson and BMW mainstay Dieter Quester.
The fact that BMW North America keep this and so many other historic racers in running condition is something we should all be thankful for: the combination of the breathtaking shape and pure livery make it the epitome of a classic BMW, run then as now by passionate racers.
from SPEEDHUNTERS
