Guide: Destined for Disappointment - a Historical & Technical Appraisal of the Maserati Bora Gr.4 Competizione
BACKGROUND
Despite having been conceived strictly as a road car, in late 1972 Maserati’s French distributor, Jean Thepenier, commissioned a Group 4 racing version of the mid-engined Bora with which to contest the 1973 Le Mans 24 Hours and end-of-season Tour de France.
In order to qualify for the Group 4 category, a manufacturer first had to complete 500 examples of its road-going base car. In 1971 (the first year of production), Maserati had reputedly completed just nine Boras followed by an additional 220 copies by the end of 1972. As this was well short of the number required for homologation, Thepenier must have hoped that Maserati’s French owners, Citroen, would either carry out some kind of fiddle or (perhaps more likely) put pressure on the Le Mans and Tour de France organisers to allow the Bora to compete in a special invitational class.
At the time, the Group 4 category was largely dominated by two marques: Ferrari and Porsche.
Using competition prepared iterations of the Daytona (dubbed the 365 GTB/4C) Ferrari’s distributor teams had famously finished fifth through ninth overall at the 1972 Le Mans 24 Hours to claim the top five positions in the Grand Touring class. Having won the GT category of the biggest World Sportscar Championship race of the year, the Ferraris also went on to finish first and second overall in the epic Tour de France.
As for Porsche, the German firm generally swept to victory in most of the other major races that season although Chevrolet and De Tomaso also collected some major wins using their Corvette and Pantera models respectively.
With Ferrari, Porsche, Chevrolet and De Tomaso all known to have further uprated machinery in the pipeline for 1973, Thepenier was determined to enter the fray and give the financially struggling Maserati outfit a major boost.
With no guarantee of acceptance into the Group 4 class, Thepenier placed his order for two suitably enhanced Boras that he hoped would be able to contest the up to five-litre Grand Touring category and thus go head-to-head with the formidable Ferrari 365 GTB/4C Daytona.
Thepenier wanted his first car ready for the 1973 Le Mans Test which took place over the weekend of March 31st and April 1st. On the Sunday, the Le Mans organisers were also set to organise a 4 Hour race to bolster attendance in which Thepenier hoped his Group 4 Bora would make its competition debut.
With this in mind, cash-strapped Maserati got straight to work and had the first car, chassis 3000, running in early March.
CHASSIS
In order to drastically reduce weight, the Bora Competizione’s pressed steel monocoque was extensively drilled out.
A double wishbone suspension layout with an anti-roll bar at each end was retained. However, the suspension mounts were suitably reinforced and stiffer, competition grade spring / damper units were installed along with thicker anti-roll bars.
Although Citroen’s advanced high pressure hydraulics were retained to control the Bora Competizione’s ventilated four wheel disc brakes, the power-assisted steering, retractable headlight, clutch command, adjustable steering column and foot pedal systems (al normally hydraulically operated) were discarded.
The brakes were uprated by way of thicker discs and F1-style four-piston Girling calipers. Brake bias was adjustable via a switch on the dash.
The standard Bora’s 15-inch diameter wheels were switched to the same Campagnolo units used by De Tomaso on their Group 4 Pantera. These cast magnesium rims retained a 15-inch diameter as per the road car, but were widened from 7.5-inches all round to 11-inches up front and 13 at the rear. Tyres were supplied by Michelin.
ENGINE / TRANSMISSION
In the engine bay was a suitably uprated version of the Bora’s all-alloy, dual overhead cam, 16 valve 90° V8.
A 4.9-litre version of the existing 4.7-litre version was used. The 4.9 unit (stroked from 85mm to 89mm) was developed for the US market to counter the effect of various emissions equipment left absent on the Competizione. 4.7-sized 93.9mm cylinder bores were carried over as usual for an overall displacement of 4930cc.
In the transition to racing trim, Maserati switched the Competizione over from wet to dry-sump lubrication in order to avoid oil starvation while cornering. Other enhancements included uprated heads, a higher compression ratio (10.5:1 as opposed to 8.5:1), four Weber 50 IDA carburettors (instead of the usual 42 DCNF type), a cold air induction pan and a free-flow exhaust.
As a result of these changes, the weight of the engine was reduced by a reputed 50kg.
Peak output went from 300bhp at 6000rpm on the normal 4.9 version to a conservatively rated 355bhp at 6800rpm. However, some sources quoted a horsepower figure in excess of 400bhp.
The familiar five-speed ZF gearbox was given synchronised ratios adapted for racing with a choice of ratios available to reflect the nature of any given contest. The original self-locking limited-slip differential was retained but an oil cooler with two electric fans was added along with a competition clutch.
BODYWORK
A series of modifications were made also to the bodywork.
At the front, the standard Bora’s pop-up headlights were exchanged for fixed units mounted underneath Plexiglas covers in enlarged cowls. The decorative trim and grilles from the front intake aperture were discarded and spot lamps positioned at each corner. Discrete brake cooling ducts were added at the base of front apron.
Down each flank, subtly flared front arches along with much bigger rear extensions were added to cover the new Campagnolo wheels. Located behind concealed panels on both B-pillars were filler caps for the two long-range fuel tanks mounted either side of the engine. Above the left-hand side fuel filler door was a circular opening inside of which was an electrical kill switch. Further back, the original sail panel vents were ditched and cooling scoops added that directed cool air all the way back to the engine’s intake system.
At the rear, the tail fascia bumper and grille were ditched. Instead of four small diameter exhausts (two per side), a pair of single large diameter exhausts poked through the exposed aperture.
Other new details included a single windscreen wiper (instead of two) and retaining straps for the front and rear lids.
INTERIOR
Inside, everything deemed unnecessary was left absent to include most of the standard upholstery, sound insulation, the electric windows and audio system.
The spartanly equipped cockpit was home to a roll cage, bucket seats with competition harnesses, simplified instrumentation and a fire system.
WEIGHT / PERFORMANCE
Compare to the standard Bora which weighed in at 1610kg, the Competizione version was 250kg lighter (1360kg).
Top speed went from 168mph to in excess of 180mph. Depending on gearing, a 0-62mph time of under five seconds would have been likely (down from 6.2 seconds).
THE FIA DECIDES
Unfortunately, within a very short space of time it became clear that the governing body would not accept the Bora Competizione as a bona fide Group 4 entry and nor would a special invitational class be organised as had sometimes been the case to accommodate other prestigious marques. Because the Group 6 Prototype class was subject to a three-litre engine limit, there was no question of the Boras running in that category either.
This left the gamble of a Prototype class being formulated at September’s Tour de France as Thepenier’s only hope to see his expensively developed Boras run in anger. In anticipation of this, Francois Migault and Jean-Pierre Jaussad were reputedly brought on board to aid development..
SUBSEQUENT MODIFICATIONS
As it quickly became clear the Bora Competizione would no longer have to comply with Group 4 regulations, a series of further modifications were made.
Most significantly, the front and rear fenders were flared quite dramatically and the large steel and glass hatch was replaced by an aluminium unit with heavily vented Plexiglas windows.
A further 150kg was saved which took the Bora Competizione down to just 1210kg.
NO PROTOTYPES AT THE TOUR DE FRANCE
Sadly, Jean Thepenier’s hope of a Tour de France entry never materialised. As had been the case in 1972, the 1973 event formed part of that year’s European GT Championship which was organised for Group 3 and 4 cars and special dispensation for Prototypes to run was not forthcoming.
PRODUCTION & SUBSEQUENT HISTORY
Two copies of the Bora Competizione were built on chassis numbers AM.117.3000 and 3001.
The first example, chassis 3000, was used for most of the testing and development work.
Because Thepenier delayed payment for the second example until the Tour de France organisers confirmed the car would not be permitted to run, Maserati were left in the lurch as their French distributor never paid for it. Chassis 3001 was subsequently sold to a Middle Eastern customer while the original car languished at Thepenier’s Paris showroom until the mid 1980s by which time it had been repainted red.
Text copyright: Supercar Nostalgia
Photo copyright: unattributed
