May 10

May 10 Guide: Lotus Esprit S1

Ben Tyer

Lotus Index

Lotus - Lotus Esprit - 1970s British Cars - 1970s Supercars - Ital Design

Background

As the 1970s dawned, Lotus looked to revamp their production car line-up.

By the middle of the decade, the Elan, Elan +2 and Europa had made way for a trio of new models called the Esprit, Eclat and Elite.

The Elite (Type 75) and Eclat (Type 76) were front-engined four-seaters wrapped in Coupe and Shooting-break body styles respectively.

Most exciting though was the stunning new Esprit (Type 79).

Launched at the Paris Motor Show in October 1975, the Esprit was a mid-engined two-seater cloaked in a fabulous wedge body penned by Giorgetto Giugiaro at Ital Design.

Notionally a replacement for the quirky and somewhat impractical Europa, the Esprit needed to offer improved performance, additional cockpit space and a more conventional appearance than its predecessor.

It would also be a step up in price and retail at a similar amount to the Porsche 911. However, Lotus were not expecting to rival the German firm in terms of production figures.

Styling for the Esprit began long before its mechanical development.

Colin Chapman first met with Giugiaro in early 1971. At this point, the Englishman was shown renders for the forthcoming Maserati Boomerang.

The Boomerang was a state-of-the-art styling exercise that would announce Maserati’s intention to produce a mid-engined supercar. Chapman approved of its fabulous lines and commissioned Giugiaro to begin work on the as-yet unnamed Lotus.

By the end of 1971, Ital Design had produced a quarter scale model, but Chapman was unimpressed with the wind tunnel readings and decided to abandon the collaboration.

Undeterred, the Italian styling house pressed on and produced a full size mock up on the lengthened and widened Europa chassis they had been supplied with.

This full-size push-mobile was then displayed at the Turin Motor Show in November 1972, where it was unveiled alongside the Boomerang. Together, the two cars made quite the impression. Such was the response, Chapman reversed his earlier decision and the project was back on track.

A fully operational prototype was subsequently completed. In the absence of an official title, it was badged IDGG 01 (Ital Design Giorgetto Giugiaro 01). This red car was followed by the first true production prototype in late 1974.

Chassis

In typical Lotus fashion, the Esprit was built on a steel backbone chassis. At 2438mm, the wheelbase was 127mm longer than the outgoing Europa. When combined with an additional 223mm of width, the new car was able to offer considerably more cockpit space.

Suspension was independent all round. The front arrangement consisted of double wishbones and coil spring/damper units with an anti-roll bar. Things were more complex at the rear. Lotus employed fixed-length driveshafts that doubled as the upper transverse links plus lower transverse links, box-section semi-trailing arms and more coil spring/dampers.

A twin circuit Girling brake system employed 9.7-inch diameter discs at the front and 10.6-inch discs at the rear. As per contemporary racing practice, the rear brakes were mounted inboard.

Steering was unassisted rack and pinion type.

For the wheels, Lotus used Wolfrace 14-inch cast alloy rims. They measured 6-inches wide at the front, 7-inches wide at the rear and originally came shod with Goodyear Grand Prix tyres.

Twin fuel tanks with an overall capacity of 68.2-litres were located either side of the engine, up against the rear bulkhead.

Engine / Gearbox

The Esprit was designed from the outset to use Lotus’s new Type 907 four cylinder engine. Short, wide and shallow, it was ideal for such an application and offered a very high output considering its low weight.

Both the block and four-valve head were cast from aluminium alloy. The engine was longitudinally mounted at a 45° angle.

In exactly the same state of tune as found in the Elite and Eclat, the Esprit engine displaced 1973cc thanks to a bore and stroke of 95.2mm and 69.2mm respectively.

With compression set at 9.5:1 and a pair of downdraught twin-choke Dellorto DHLA 45 carburettors, peak output was 160bhp at 6200rpm and 140lb-ft at 4900rpm.

By today’s standards, such figures may not seem particularly impressive, but in a package that weighed less than 900kg, the Esprit offered comparable performance to its rivals.

As the Renault gearbox used in the Europa could not handle the Esprit’s torque load, Lotus had to find a suitable replacement.

They decided on the all-synchromesh Citroen C35 five-speed transaxle as used in the Citroen SM and Maserati Merak. Importantly, Citroen were able to guarantee a supply for at least ten years.

Although available with a variety of internal and final drive ratios, Lotus eventually chose the exact same set up used by the SM.

Bodywork

Whereas Giugiaro had to dramatically water down the Boomerang concept for the production-ready Maserati Bora, the Esprit retained its concept car looks.

The design was a mix of flat surfaces and straight edges.

As usual for Lotus, the bodyshell was made from fibreglass.

Each retractable headlight housed two driving lights. The tail lenses were sourced from the Fiat X1/9.

Brightwork was restricted to the front and rear windscreen surrounds, the door handles and the wheels. The bumpers, side window frames and body swage line were black.

A rudimentary chin spoiler appeared something of an afterthought, but cosmetically, the Esprit was a match for anything offered by Ferrari or Lamborghini.

Interior

In the cockpit, bucket seats with fixed backs were divided by a bulky transmission tunnel

All the instrumentation was housed within a floating binnacle, the ends of which were angled inwards towards the driver. Veglia supplied the S1’s green-faced gauges that were located behind a simple two-spoke steering wheel.

Large read outs for road and engine speed were flanked to the left by smaller dials for oil pressure and water temperature. To the right were gauges for battery amps and fuel.

A variety of rocker and toggle switches plus the ventilation controls were housed at the angled ends of the binnacle.

Buyers could choose from a variety of upholstery options to include full vinyl, vinyl and fabric or full fabric with tartan inlays for the seats and door panels.

Electric windows were standard.

Weight / Performance

All told, the Esprit weighed in at just 898kg.

It had a top speed of 124mph and 0-62mph time of 6.6 seconds. However, so good were the Esprit’s chassis dynamics, most thought it capable of handling substantially more power.

Production Begins

Following its launch at the Paris Motor Show in October 1975, the Esprit entered production in May 1976. The first deliveries took place in June.

The car was praised for its good looks and superb handling, but requests for more oomph and greater refinement were common.

USA Version

In early 1977, US deliveries began of a smog-equipped S1.

Stifled by heavy emission control systems, this Federal version put out 140bhp.

However, unlike many Italian exotics of the period, the Esprit was at least officially available in North America. By contrast, Lamborghini and Maserati were practically frozen out of the US market during the mid-to-late 1970s. Ferrari were only permitted to sell their V8-engined models.

Those cars that did make it through were routinely blighted with the ugliest impact-absorbing bumpers imaginable. To Lotus’s credit, the only cosmetic alterations required to the Esprit were side marker lights at each corner.