Tuning topics

Alpina's Ultimate BMW

A 152 mph road saloon

THE LITTLE TOWN of Buchloe, nestling deep in Bavaria an hour's drive from Munich, has nothing to commend it in the guide books, but to BMW enthusiasts across the globe it represents Mecca, home of BMW-Alpina, foremost tuners of the Munich marque. While Alpina have had immense success in Saloon car racing and rallying, outright victory in the 1970 European Touring Car Championship marking their most notable achievement, their bread and butter is road car tuning and Alpina 2002s are among the most desirable and numerous of tuned road-burners on the Continent. However good these may be, they pale into insignificance at the side of Alpina's latest fast road car, a remarkable BMW 3.0 CSI, which combines saloon car comfort and accommodation with 0-100 m.p.h. acceleration in 13.9 sec., a maximum speed of over 150 m.p.h. and sheer driving exhilaration. I came back from a recent test of this car in Germany and Austria astounded by its shattering performance, in a class with some of the most exotic sports cars. Alpina's comprehensive modifications have put this dramatic CSI, into the "one of the most desirable cars in the world" bracket, and at roughly £8,000, one of the most expensive.

The firm responsible for this impressive lightweight coupé was founded and is headed by Burkard Bovenseipen, who made his fortune on the stock market before investing it in the tuning business only eight years ago. He was already a motor sport enthusiast, had done some racing, mainly in a BMW 700 and saw a lack of good tuning facilities in Germany. From early beginnings fitting carburetter kits to BMW 1500s in his father's Alpina typewriter factory at Kaufbeuren, 18 kilometres down the road from Buchloe, Bovensiepen has moulded his business into what is believed to be the largest tuning-establishment in Europe. Eighty employees are involved in this almost completely self-contained small factory complex, which Bovensiepen runs on an industrial basis, designing, producing, distributing tuning equipment and accessories, modifying customers' cars in large volumes, building road, racing and rallying engines to pre-determined specifications, developing new specifications. Constructing and racing their own cars and building rally engines for use by Jochen Neerpasch's BMW works competition department.

Alpina are currently pre-occupied preparing a brace of Gp 2 CSLs for their own attack on the European Touring Car Championship and a single identical car for BMW Concessionaires GB Ltd., to contest the British Saloon Car Championship and a few ETC rounds. Brian Muir has forsaken his Capri to drive for both Alpina and the Concessionaires. Initially he'll have about 340 b.h.p. under foot using slightly enlarged versions of the CSL's 3,002 c.c. six-cylinder engine, growing later to about 355 b.h.p. when Alpina complete development of a 3,300 c.c. unit. As Alpina have managed to reduce the CSL's weight from 1,165 kg. in standard form to 1,060 kg. ready for the circuit, compared with 1,250 kg. for the all-steel racing CSs which proved too heavy to be competitive last year, Bovensiepen believes that Muir will stand a good chance of outperforming the hitherto invincible Cologne Capris.

No firm could be more qualified to modify the CSL, as it was largely at Alpina's suggestion, after they'd experimented with a CS, that BMW produced the CSL in the first place. Indeed, Alpina carried out much of the development work on the production CSL for BMW and their involvement is recognised by the fitment of Alpina alloy road wheels as standard. Just to recap on W.B.'s description of the CSL in last month's issue, it's a lightweight version of the injected 3.0 CSI, introduced unashamedly specifically to homologate it for 3.0 CSi. Bonnet, boot and doors are of aluminium, the shell is made of lighter gauge steel pressings, there's less sound damping material, engine capacity is increased from 2,985 c.c. to 3,003 c.c. to take it over the 3-litre class limit, a limited-slip differential is standard, fuel tank capacity is increased to 17 gallons and the alloy wheels have 7J instead of 6J rim's, their extra width accommodated by wheel arch extensions. Cars for the British market, like the one used by W.B. and MOTOR SPORT'S Production Manager to visit 10 European capitals in four days, have glass windows all round, the side ones electrically operated, and steel bumpers, whereas the lefthand drive German market car used as the basis for this Alpina test car, had Perspex all round, apart from a laminated screen, manual winders and plastic bumpers.

The Alpina car looked more brutal than W.B.'s example, accounted for by the lack of a front bumper, altered tide heights front and rear and a striking blue and red paint scheme complete with the revealing description "BMW Alpina" on each front wing and the tail panel. Both were fitted with Alpina's glassfibre front spoiler/air dam identical to those fitted to the racing coupés, which are claimed to add three or four m.p.h. to top speed, reduce fuel consumption, improve resistance to aquaplaning and improve high speed stability.

Such fantastic performance signifies quite radical work on the o.h.c. engine, as indicated by an increase from the production output of 200 b.h.p. DIN at 5,500 r.p.m. to 260-265 b.h.p. DIN at 6,800 r.p.m. A complete engine rebuild took up a large slice of the estimated £1,800 conversion on this particular car. The block was bored out 0.5 mm. to 89.5 mm. to increase capacity from 3,003 c.c. to 3,020 c.c., using special forged pistons on polished standard Con-rods and the standard flywheel was lightened. To this was attached a 240 mm. Fichtel and Sachs clutch with alloy pressure plate, 12 mm. larger than the production clutch and the same size as the racing ones, though with conventional facing material rather than the sintered bronze of the racer. The complete bottom end assembly was of course balanced.

A lot of work was put into the cylinder head, the main part of which was to convert the triple-hemisphere combustion chamber shape to fully hemispherical, together with polishing the ports and valves. The head was shaved to an extent determined by the pistons and deck height to reduce the combustion capacity after chamber work to an amount which gave a compression ratio of 10.5:1 instead of 9.5:1. A mild improvement in timing comes from the extra lift and dwell of an Alpina 300-degree sports camshaft. Alpina threw away the Bosch electronic fuel injection, replacing it with a Kugelfischer mechanical pump and their own design of injection system, using butterflies rather than the sliding throttle device used on the 3-litre racing engines, fairly short inlet trumpets were led into a special air-cleaner and silencer fed with cold air from the grille. The production exhaust manifold was retained, leading into an enlarged system exiting in the normal place under the tail. Thermostatically controlled oil cooler and electric fan were added.

W.B. mentioned that he'd have appreciated a five-speed gearbox in place of the non-too close ratios of the standard four-speed box; he'd have been ecstatic about the ratios in the special fire-Speed ZF box fitted to this tuned car: 2.99, 1.76, 1.30, 1.0 and 0.87. Fifth was technically an overdrive, but by lowering the final drive ratio from 3.45 to 3.89, Alpina enabled the CSL to pull maximum revs in this gear. The firm built this gearbox themselves using non-standard ratios, but Herr Hovensiepen doubts whether he'll make the box generally available as it has an inherent noise problem, chattering in the lower gears and howling in the higher ones, which the ZF box with normal ratios of 3.85, 2.40, 1.67, 1.26 and 1.0 doesn't have. The spread of the ratios on the latter box doesn't suit the car so well and because of its low gearing it can only be offered with the standard 3.45 final drive or a 3.27.

Speeds in the gears were staggering and made a mockery of the British 70 m.p.h. limit and the new German off-autobahn limit of 100 k.p.h.: 1st—44 m.p.h.; 2nd—75 m.p.h.; 3rd—101 m.p.h.; 4th—132 m.p.h. ; 5th—152 m.p.h.

Even though the standard CSL has excellent roadholding and handling, the calibre of this car's performance made further suspension improvements desirous. From my point of view the handling improvement I appreciated best was the basic one of replacing the power steering with a manual ZF box, instilling the steering with much more feel and precision yet remaining reasonably light by virtue of the standard 18.9:1 ratio. However, I felt that this ratio was too low and would have liked to try the car fitted with Alpina's racing box of 13.6:1 ratio, which shouldn't make things unbearably heavy on road tyres.

Modifications to the suspension included adding negative camber to the front wheels, Bilstein struts and rear dampers developed by Alpina in conjunction with the manufacturers, increased rate versions of the standard progressive coil springs which use thicker wire at the top than the bottom and are an original Alpina design, and adjustable anti-roll bars, 22 mm. thick at the front and 18 mm. at the rear. The seven 14 in. Alpina alloy wheels were retained, but the size of the rear Pirelli CN 36 tyres was increased from 195/70 to 205/70.

Starting was usually instantaneous when hot or after being left outside in the snow all night. A Dymo tape note on the facia warned drivers to let the oil pressure build up before driving off, visible on the instrument in the three-gauge Alpina instrument panel in the middle of the facia, the other additional instruments being for oil temperature and final drive temperature, the needle on the last gauge refusing to move until cruising speeds of over 100 m.p.h. were maintained.

The clutch was heavy and abrupt, this rather than engine characteristics demanding three or four thousand r.p.m. on the rev. counter. to avoid stalling on getaway. It paid to be careful with the throttle when trying to leave the mark quickly, for excessive revs. provoked violent wheelspin and squealing, burning rubber all the way through to third, the tail stewing from side to side in anguish in spite of the limited slip differential and a trace of axle judder appearing. I'm sure I don't need to qualify the resultant acceleration; the figures tell their own story. Engine and exhaust noise rose to a crescendo as the fixed backs of the Scheel bucket seats tried to push the spine through the body and the rev, counter needle darted to and fro from 7,000 r.p.m. between the five gears. This same shattering acceleration continued all the way up to the end of the 240 k.p.h. speedo (149 m.p.h.), tailing off for the last three m.p.h.

Ideal cruising speeds in fifth gear were anywhere between 70 m.p.h. and 145 m.p.h., the engine showing no signs of over-exertion at the higher speed and stability remaining unimpaired, a tribute to the effectiveness of the spoiler. At the lower speed the CSL literally felt to be crawling and was deceptively slow at maximum speed, when the smooth engine's normal whirr had risen to a roar and wind noise grew around the flapping plastic side windows. At the other end of the scale, the engine was quite happy traversing heavy Munich traffic at 1,600 r.p.m. in the gears. Below that, transmission judder set in.

Much of my test was conducted in atrocious conditions of rain and snow and while moderately wet surfaces failed to disturb adhesion, heavy rain on the autobahns and studded-tyre rutted main roads showed up a serious aquaplaning problem because of the fat tyres, forcing me to curtail speed below that of narrow tyred family saloons. Rather ignominious and frustrating.

Roadholding was superb in the damp and on the occasional pieces of dry road I encountered. The limit of adhesion was so high that I never found it and I gave up trying because the impression was that it would appear very suddenly and £8,000 is a lot of motor car to drop off the edge of a mountain. After initial understeer it maintained a fairly neutral stance with very little roll and refused to budge. Unfortunately the steering lacked feel, largely because of that low gearing again, though the Alpina 15-in, four-spoke leather wheel was extremely comfortable and just the right size. The brake pedal too didn't transmit much feel, being very light with too much servo. Braking power was fantastic, however, the double-dual circuit -system working calipers on four-wheel ventilated disc brakes. Alpina had removed the risk of overheated brakes and so improved resistance to fade by increasing the thickness of the 270 mm. front discs from 22 mm. to 28 mm., leaving the standard 200 mm. outboard rear discs alone.

Ride was very firm, but the size and weight of the car kept the pitch frequency at a reasonable level, the shaped Scheel seats ensuring a high degree of comfort. In spite of the two criticisms regarding brakes and steering, the overall impression of driving this superb beast will remain with me for a long time to come. Alpina's ultimate road-going BMW is genuinely race-bred, for many of the modifications have come directly from experience with circuit cars and the 260 plus-b.h.p. engine isn't far removed from those used in the early racing coupés, yet it remains a perfectly practical road machine. In many ways it's reminiscent of driving a racing Jaguar D-type or similar on the road, because sheer power makes it flexible and docile, yet when unleashed it goes like the proverbial.

Similar Alpina modifications are available for the full range of BMW six-cylinder saloons and coupés, with an alternative engine conversion for carburated cars incorporating triple 45 DCOE Webers, which restrict power output to 250 b.h.p. As mentioned below, these and all other Alpina conversions are now available through the new Sportpart organisation introduced by BMW Concessionaires GB Ltd.—C.R.

Performance

0-40 k.ph. (25 m.p.h.) . . 2.3 sec.
0-60 k.ph. (37 m.p.h.) . . 3.2 sec.
0-80 k.ph. (50 m.p.h.) . . 4.8 sec.
0-100 k.ph. (63 m.p.h.) . . 6.4 sec.
0-120 k.ph. (75 m.p.h.) . . 8.4 sec.
0-140 k.ph. (87 m.p.h.) . . 11.0 sec.
0-160 k.ph. (100 m.p.h.) . . 13.9 sec.
0-180 k.ph. (112 m.p.h.) . . 18.5 sec.
0-200 k.ph. (124 m.p.h.) . . 25.0 sec.

Maximum speed: 152 m.p.h.

Speed in gears: 1st—44 m.p.h.; 2nd—75 m.p.h.;
3rd—101 m.p.h.; 4th—132 m.p.h.

Fuel consumption: 16.9 litres per 100 km.