Feb 14

Feb 14 Guide: Lotus Esprit Turbo

Ben Tyer

Lotus Index

Lotus - Lotus Esprit - Lotus Esprit Turbo - 1980s British Cars - 1980s Supercars - Ital Design

Background

Lotus conceived the Esprit Turbo as a flagship in a similar vein to Porsche’s 930.

The British firm initially launched their new model as the super exclusive Essex Commemorative edition to reflect an F1 sponsorship agreement with David Thieme’s Essex Overseas Petroleum Company.

Thieme was a flamboyant character and, as part of his $8m two-year F1 sponsorship package for 1980 and 1981, the soon-to-be-released Esprit Turbo was re-branded and given an extraordinarily high specification.

The plan was that the first 100 Esprit Turbos would be completed in Essex trim: Monaco Blue paint with chrome and red stripes and a scarlet interior. The expensive additions of air-conditioning, full leather upholstery, Sundym glass and a state-of-the-art roof-mounted Panasonic stereo would be standard equipment.

Thieme was the driving force behind the Essex Commemorative specification, but its flashy colour scheme was not to everyone’s taste and the enormous price meant demand was subdued.

Soon after launch, Lotus quietly began offering the Esprit Turbo in more conventional colour schemes and around half of these early cars were completed without the Essex livery.

When Thieme was arrested by Swiss authorities in March 1981, Lotus dropped the Essex Commemorative package entirely. Credit Suisse had extended Thieme a credit line for oil spot trading activities and accused him of committing a $7.6m fraud.

After the 1981 Monaco Grand Prix, Thieme disappeared from view altogether.

Lotus replaced the Essex logos on their F1 cars with those of long-term sponsor, John Player Special, and the whole shady episode was quickly forgotten.

In April 1981, Lotus made several changes to the Esprit Turbo that kick-started demand for their highly accomplished range-topper.

Most importantly, by dropping the air-conditioning, roof-mounted stereo, Sundym glass and leather upholstery (now optional extras), Lotus were able to reduce the car’s price by over 15%.

They also switched to single-piece BBS cross-spoke wheels as the original split rim Compomotives were not only very expensive, but also found to leak air. Wheel sizes were unchanged: 15 x 7-inches at the front and 15 x 8 at the rear.

Demand quickly picked up.

Chassis

The Turbo was built on a heavily revised version of the original Esprit’s steel backbone chassis.

Beefed up with wider box sections, new suspension mounting points and a new subframe for the engine and transmission, it also offered improved access to the engine and had space for a V8 motor that was secretly under development.

Importantly, the chassis was zinc galvanised and came with a five-year anti-corrosion guarantee.

Wide track front suspension comprised upper wishbones, lower transverse links, coil springs and an anti-roll bar. Most of this equipment was imported from the Elite. At the back were non-parallel unequal length double transverse links, radius arms and coil springs. An upper link had been added to the rear to alleviate strain on the half-shafts.

The brakes had also been improved compared to normally-aspirated variants with larger discs now fitted all round. The fronts had a 10.5-inch diameter while the inboard rears measured 9.7-inches. A bigger brake master cylinder and servo were installed as well.

Engine / Gearbox

Turbocharged Esprits came with a special Type 910 engine which had been almost completely redesigned compared to the standard power unit.

It was another all-alloy inline four with a 16-valve dual overhead camshaft head, but now incorporated dry-sump lubrication, a bigger oil cooler and camshafts that had a different profile to those in the normally-aspirated engine.

Lotus fitted a Garrett AiResearch T3 turbocharger which ran at a conservative 0.55 bar. It was mounted downstream of the Dellorto carburettors for improved throttle response, better fuel / air distribution and improved wet fuel handling when started.

The twin-choke sidedraught Dellorto carburettors were of the DHLA 40H variety and the compression ratio was reduced to 7.5:1.

Both turbocharged and normally-aspirated engines displaced 2174cc thanks to a bore and stroke of 95.2mm and 76.2mm respectively.

Peak output of the turbocharged motor was 210bhp at 6250rpm and 200lb-ft at 4500rpm.

Away from the headline figures, Lotus paid considerable attention to minimise throttle lag and poor low speed torque. Accordingly, the Type 910 engine ranked among the most refined and flexible turbocharged power units of the era.

Transmission was via a five-speed Citroen gearbox and single-plate clutch.

Bodywork

Aside from the lack of Essex graphics (simple ‘Turbo Esprit’ decals were now applied to the nose and sides), cosmetically, nothing changed.

Having penned the original Esprit and subsequent S2 variant, Giorgetto Giugiaro’s Ital Design studio had also executed the Turbo revamp.

Giugiaro’s Turbo body kit included new bumpers, a full width front spoiler, side skirts, a louvred rear hatch, an integrated rear spoiler and deeper rear apron. Aside from the bumpers and rear windscreen louvres (which were finished in satin black), almost everything else was body coloured.

The front spoiler housed intakes for the radiator and oil cooler while the side skirts contained fresh air ducts for the engine compartment. More air was fed to the engine via intakes located behind each rear three quarter window.

All things considered, the Esprit Turbo was one of the best looking supercars of the 1980s.

Interior

The cockpit was also the same as before, although it now came without the expensive Essex Commemorative upgrades which were all still available as optional extras.

Instrumentation was housed in a rectangular binnacle angled towards the driver at either end.

Ventilation controls and the stereo were mounted on a central control panel ahead of the gear lever.

Although the cockpit had neither the quality of a Porsche or the style of a Ferrari, it was well laid out, reasonably well constructed and there was sufficient space for drivers over six feet tall.

Owing to the bulky transmission tunnel, the handbrake had to be mounted on the sill.

Electric windows, electric mirrors, a heated rear window and half leather trim were standard.

Options

Optional extras included full leather upholstery, metallic paint, an uprated audio system and air-conditioning.

Weight / Performance

Weight was 1148kg, top speed was 150mph and 0-62mph took 5.6 seconds.

Production Begins

Lotus F1 driver, Nigel Mansell, was an early recipient of a post-Essex Esprit Turbo. Mansell took delivery of his black John Player Special-liveried example (UAH 272W) in July 1981.

Production continued without any major changes for nearly two years.

Production Changes

In March 1983, Lotus switched to a wet-sump lubrication system as prolonged testing convinced them the dry-sump arrangement was not needed. Engine output was unaffected.

Around the same time, the matt black bumpers were changed to body colour.

In 1985, some minor changes were made to the bodyshell and front suspension. The anti-corrosion warranty was extended to eight years.

Esprit Turbo HC

The final incarnation of the original Giugiaro-designed Esprit Turbo was unveiled at the Geneva Motor Show in March 1986 and went into production that October.

As its name suggested, the Esprit Turbo HC most notably came with a high compression engine.

The compression ratio was raised from 7.5 to 8.0:1 and boost pressure was increased from 0.55 to 0.65 bar.

Output rose from 210bhp at 6250rpm to 215bhp at 6000rpm. There was also a useful torque gain with 220lb-ft now on tap at 4250rpm compared to 200lb-ft at 4500rpm for the outgoing variant.

Other upgrades introduced at the same time included an uprated cooling system, wider and lower seats, enlarged footwells, a revised front spoiler with bigger radiator intake and wider section tyres.