GT40 Evo - a Historical & Technical Appraisal of the Mirage M1
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BACKGROUND
In October 1966, John Wyer was visiting New York on business when he took a call from Gulf Oil Executive Vice President, Grady Davis.
The two men had met for the first time at the Sebring 12 Hours in March, after which Davis placed an order for a Mk1 GT40 (chassis P/1049). Back then, Wyer merely ran Ford Advanced Vehicles (FAV) which handled GT40 production and certain aspects of the racing programme. However, by the time of his visit to New York, Ford had agreed to sell FAV to Wyer, along with the GT40 production rights.
Grady Davis was a big motor racing fan and had been extremely impressed with his new car which Dick Thompson successfully raced in a number of SCCA and USRRC events.
As Gulf Oil was looking to expand its operations in Europe, Davis thought promotion through motor sport Would be the ideal platform to raise the company’s profile.
Davis sent Gulf’s private plane to New York and Wyer travelled to Pittsburgh for a meeting. Here, the two men thrashed out a sponsorship deal for 1967 and 1968 that would see John Wyer Automotive Engineering (JWAE) campaign cars under the Gulf Racing banner.
Rather than compete with an existing GT40, the 1967 programme would focus on an uprated variant albeit one still intended for the Group 4 Sports class. Wyer and Davis thought the GT40 platform still had considerable potential and, with that in mind, JWAE set about creating a super GT40: the Mirage M1.
Lighter, lower, more powerful and better aerodynamically than the existing GT40, the Mirage M1 was expected to be the class of the Group 4 Sports category which had a 50-car production requirement and permitted engines of up to five-litres. Such was the level of expectation, JWAE even thought that on ‘power’ as opposed to ‘handling’ tracks the Mirage would stand a good chance of beating the top flight Group 6 Prototypes which of course had no minimum production requirement nor any limit on engine displacement.
As the Mirages would not be ready until April, JWAE initially transformed Grady Davis’s personal Mk1 GT40 into a fully fledged competition car for the first couple of races in 1967. An orange stripe and Gulf branding was added to the otherwise dark blue machine.
Jacky Ickx and Dick Thompson finished sixth overall and first in the five-litre Sport class driving P/1049 at Daytona. They subsequently retired at Sebring with engine trouble. The first Mirage M1 was then tested at Snetterton on March 21st. Unlike P/1049, the Mirages were painted what became the iconic Gulf Racing colours of powder blue and orange.
CHASSIS
The M1 used the original GT40’s lower semi-monocoque structure (made of steel), but the top part was redesigned and fabricated from aluminium. This was done to give the M1 a narrower, more rounded cockpit profile that was better able to cut through the air.
Additionally, the front section of the chassis was squared off.
As usual, subframes were fitted front and rear for the engine and suspension.
The revised tub and more sophisticated suspension (with lower roll centres) was designed by Len Bailey. However, the GT40’s basic suspension layout was retained. This comprised double wishbones at the front with dual trailing links, transverse top arms and inverted lower wishbones at the rear.
Coil springs with adjustable dampers were fitted all round along with an anti-roll bar at either end.
Bigger ventilated disc brakes were installed. The fronts came with flexible air hoses and aluminium muffs that fed cool air over the braking surface.
Halibrand magnesium alloy wheels were shod with Firestone tyres.
A flexible bag-type fuel tank was fitted in each sill.
ENGINE / TRANSMISSION
Four different variants of the eponymous Ford V8 were used during the M1’s 1967 campaign.
For the car’s public debut at the Le Mans Test weekend in early April, largely standard units were installed.
These 4.7-litre 90° V8s used cast-iron for the block and pushrod heads. Displacement was 4736cc thanks to a bore and stroke of 101.6mm and 72.9mm respectively. They came with four twin choke Weber 48 IDA downdraught carburettors, modified valve covers, an uprated alternator and racing exhaust system.
With a compression ratio of 10.0:1, peak output was officially 380bhp at 6500rpm and 330lb-ft at 5500rpm. However, the horsepower figure was probably closer to 400bhp for the M1.
By the time the M1 made its race debut at the Monza 1000km two weeks later, JWAE had fitted five-litre engines that had been stroked to 4942cc and which pumped out around 440bhp. Aluminium Gurney Weslake heads were fitted from mid May.
At the M1’s second race, the Spa 1000km in early May, JWAE’s lead car was fitted with a 5.7-litre Holman Moody engine that pumped out around 500bhp. The decision to go for an engine bigger than the Group 4 class limit of five-litres was a consequence of the FIA’s decision to categorise the M1 as a Group 6 car which, although appealed by JWAE, seemed unlikely to be overturned.
Regardless of which engine type was used, transmission was always through a five-speed ZF DS25 gearbox with triple-plate Borg & Beck clutch and limited-slip differential.
BODYWORK
Len Bailey’s redesigned bodywork was noticeably smoother than the original.
The Mk1 GT40’s engine cooling scoops mounted down each flank and on each sail panel were deleted in favour of a single NACA duct located high up behind each side window.
The cockpit was given a narrower, more aerodynamic profile similar to the latest generation of Ferrari Group 6 cars.
The rear clip was home to bulbous fenders and a more pronounced rear spoiler. A Gurney flap was routinely riveted in place for additional downforce.
In isolation, the slippery Mirage M1 appeared little changed, however, alongside a regular Mk1 GT40 the difference was stark.
Body panels were fashioned exclusively from the lightest fibreglass-carbon composite available.
INTERIOR
Interior appointments were much like the standard competition-spec. GT40.
Directly behind the three-spoke leather-rimmed steering wheel was a full width black metal dash with an instrument binnacle that encroached well into the passenger-side of the cockpit. All the usual gauges were retained.
Wedged in between the wide sills and the narrow transmission tunnel were a pair of vented bucket seats trimmed in fire-retardant fabric.
As per every GT40 racing car, a right-hand drive layout with right-hand gear change was employed. Similarly, cockpit access was made easy by virtue of doors that cut substantially into the roof.
WEIGHT / PERFORMANCE
As a consequence of the various weight-saving measures employed, the Mirage M1 likely tipped the scales a little less than a regular circa 910kg Mk1 GT40 in competition trim.
Top speed was likely in the region of 210mph.
A 0-62mph time of comfortably under four seconds would have been possible with the shortest possible gear ratios.
PRODUCTION
Three examples of the Mirage M1 were originally completed for the 1967 season: chassis M10001, M10002 and M10003.
COMPETITION HISTORY
The M1 made its public debut at the annual Le Mans Test weekend where two cars were on hand. Tellingly, the Le Mans governing body (the Automobiles Club de l’Ouest) put the Mirages in the Group 6 Prototype category instead of the Group 4 Sports class which set the trend for the rest of the year.
Chassis M10001 posted sixth fastest time overall and third quickest in the five-litre Group 6 Prototype class while chassis M10002 only did a few shakedown laps having been crashed on its maiden lap owing to a defective front brake.
The Mirages subsequently made their race debut at the Monza 1000km two weeks later, both now with five-litre engines. As had been the case at the Le Mans Test, the M1s were placed in the Group 6 Prototype class, a decision that JWAE appealed and which the FIA’s judgement was expected in May.
M10001 (allocated to Jacky Ickx / Alan Rees) qualified fourth but posted a DNF as a consequence of ignition trouble. M10002 (David Piper / Dick Thompson) started fifth but its run was beset with mechanical niggles and the car eventually placed ninth.
At the Spa 1000km, JWAE debuted a new chassis with 5.7-litre engine for Ickx / Thompson (M10003) which qualified second and went on to record a famous victory in what were frequently horrible conditions. The five-litre sister car of Piper / Rees qualified sixth but span off early on.
Three weeks after the victory at Spa, JWAE was dealt a blow when the FIA decided the Mirage M1 was not a Ford and would have to participate in the Group 6 class. It therefore continued to race against purpose built Prototype machinery for the rest of the year.
More bad news followed when Dick Thompson had a big crash in chassis M10002 during practice for the Nurburgring 1000km at the end of May. The car was a write off. Meanwhile, sister chassis M10001 for Ickx / Attwood qualified ninth but retired with a double puncture when lying third.
At the Le Mans 24 Hours, Jacky Ickx was back in the Spa-winning M1 (chassis M10003) which he shared with Brian Muir. The sister car (M10001) was entered for David Piper and Dick Thompson. Both machines were now running 5.7-litre engines.
Ickx / Muir qualified 15th and Piper / Thompson were 16th, but the two cars each suffered an engine failure during the build up and JWAE had no spare power units. John Wyer therefore decided to change back to five-litre engines for the race, but the scrutineers pointed out this could not be done as the cars still carried the larger fuel tanks for the over five-litre class. Luckily, Ford supplied a pair of 5.1-litre engines that enabled the Mirages to race.
Somewhat unsurprisingly given their largely un-tested nature, engine problems accounted for both cars: Ickx / Muir went out in the fourth hour and Piper / Thompson in the fifth.
The day after Le Mans, which had been the fastest on record, the FIA stunned the racing fraternity by announcing that Group 6 Prototypes would be limited to three-litre engines for 1968 in an attempt to reduce speeds.
Ford, Ferrari and Chaparral decided to quit.
As for JWAE, John Wyer elected to run Mk1 GT40s for 1968. The GT40 qualified for the Group 4 Sports class on account of more than 50 having been produced. As cars of up to five-litres were permitted in Group 4, the GT40 would have a two-litre advantage over the new generation of Group 6 Prototypes.
JWAE contested just one more round of the 1967 World Sportscar Championship: the Brands Hatch 6 Hours on July 30th.
A single entry was filed for Pedro Rodriguez / Dick Thompson who qualified ninth in their 5.7-litre car. Unfortunately, on lap 66, Thompson overcooked it at Clearways and stuffed the M1 into the barrier. The driver was uninjured, but the car sustained sufficient damage that its race was over.
That was the last time the Mirages were seen at World Championship level. However, JWAE entered the brace of remaining M1s for two races in Sweden over the summer.
First up was the Swedish Grand Prix, a 20 lap race at Karlskoga in mid August.
JWAE took M10003 for Jacky Ickx and M10001 for local hero, Jo Bonnier. Both cars had 5.7-litre Holman Moody engines. Ickx put his car on pole and Bonnier started third. They eventually came home in a 1-2- formation finish.
On September 24th, the Skarpnack airfield was the location for the 20 lap Stockholmsloppet which supported the weekend’s international Formula 3 race.
This time, Bonnier emerged as the victor driving M10001 with team-mate Paul Hawkins second in M10003.
During the middle of October, one 5.7-litre Mirage (chassis M10003) was taken to France to contest the Paris 1000km non-championship event around Montlhery. Jacky Ickx and Paul Hawkins started from pole and ploughed through the rain to take the M1’s fourth win of the year.
JWAE’s final outing of 1967 came at the Kyalami 9 Hours in mid November which was the opening race of the 1967 South African Springbok series. Chassis M10001 was selected for Jacky Ickx and Brian Redman to drive. They qualified third and took another well-deserved win.
SUBSEQUENT HISTORIES
At the end of the 1967 season, both remaining Mirage M1s were retired from competition duty.
M10001 was retained by JWAE in its original configuration.
M10003 was rebuilt into a Mk1 GT40 (chassis P/1074) and raced by the team in 1968.
As for M10002, that chassis had been an insurance write off after Dick Thompson’s practice accident at the Nurburgring and the damaged car saw at JWAE’s facility in Slough.
One never completed Mirage M1 tub also existed and this too was transformed into a Mk1 GT40 which saw action with JWAE in 1968 (P/1075). That year, the Gulf-backed GT40s won six World Championship events including Le Mans on their way to taking the title.
1968 KYALAMI 9 HOURS
In November 1968, JWAE wheeled out the sole remaining car still in Mirage M1 trim (chassis M10001) for the Kyalami 9 Hours which was organised outside the auspices of the FIA and still permitted over three-litre Group 6 Prototypes to compete.
M10001 was taken to South Africa for Jacky Ickx and David Hobbs who qualified third and secured the race for JWAE for the second year running.
Afterwards, M10001 was sold to privateer Malcolm Guthrie who had crashed his Mk1 GT40 badly enough that the car could not be locally repaired. To continue in the Springbok series (for which the Kyalami race had been the season opener), Guthrie concluded a deal with John Wyer to purchase M10001 which he continued to race into 1969.
Text copyright: Supercar Nostalgia
Photo copyright: Ford - https://www.ford.com, the ROFGO Gulf Heritage Collection - https://www.rofgo.com/ & Duncan Hamilton ROFGO - https://www.dhrofgo.com/
