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Lotus Esprit X180 Concept Car

The New Esprit – Lotus Design’s First Creation

Peter Stevens the Chief Designer

Norwich lies approximately 150 km north-east of London in the county of Norfolk. Lotus has had its headquarters in the rural part of England since 1966. It was here in November 1985 that sketch and clay model presentation for the next generation Esprit were presented to Senior Management. It was approved for production by the Lotus board in January 1986, immediately following the acquisition of Lotus by General Motors.
As Readers will know, the first series Esprit which debuted 12 years ago (a mock up being shown at the Turin Show 16 years ago in 1972) was a Giugiaro design. That he continued to maintain good relations with Lotus there after was clearly evident for the shape of the Lotus Etna concept model displayed at the Birmingham Show in 1984. Etna was developed with the support of Chief Executive Mike Kimberley, who took over the reigns of management at Lotus after the death of it’s founder Colin Chapman. Giugiaro was not the only Designer to be working with Lotus at the time, however. Another was Peter Stevens, who was featured in issue 49 of CAR STYLING.
Stevens turned freelance when he left Ogle Design in 1975, and worked for a large number of Clients, one of which was Lotus. His facelift proposal for the Excel went into volume production with practically no changes made to it, and he has been treated as a Lotus employee ever since.
Before there was any design organisation at Lotus Engineering Ltd, the development arm of Group Lotus Plc, Stevens started work on the development of the new Esprit with the assistance of the Lotus engineers. Lotus Design was inaugurated in June 1986, after the clay model of the new car had been approved. Julian Thomson and Simon Cox (whose graduation works were introduced in issues 48 and 57 of CAR STYLING respectively), who like Stevens are RCA graduates, joined Lotus at the time, and Andy Harrison moved across from the engineering division where he had been a trim Designer.
Kimberley set the development team an August 1, 1987 target for getting the revised Esprit into production. Volume production development was completed in just 19 months after model approval, and the car had its debut on schedule at the London Motor Fair in October. “The success of this program is a result of the Lotus philosophy of using a small dedicated team of Designers and engineers working closely with one another in a parallel process of development, rather than a sequential program,” relates Stevens. Put the other way, he is saying that the project would not have been so successful if the help of a designer outside the company had been sought. While Stevens did not make any express reference to it, one reason for Lotus not using Giugiaro can probably be found here.



From line to surface

The revised model has a shape which is readily identifiable as an Esprit, and it retains the image of its predecessor quite clearly. Nor does Stevens deny this, “The design objective was not to produce a totally new car, but rather to attend to a number of design improvements identified before the project started. The Giugiaro designed car still has an excellent overall stance and proportion, and observing the restraint of using an almost identical backbone chassis, we had only limited latitude in radically changing the shape of the car.”


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Final rendering the of Esprit Turbo by Julian Thomson


To retain the excellent proportions of its predecessor, Stevens kept exactly the same A-pillar angle in the new car. While in its individual parts it may not resemble the first series Esprit too closely, the fact that it projects a “very much an Esprit” impression when seen overall is probably due to the A-pillar. This is one key point in the design of the new model. Another lies in the differences between the old and new models. To borrow Steven’s description, “ The new Esprit can be seen as being of a “line” dominated car, and more as a surface derived car.” It is not simply a question of softening the shape, the whole styling basis has changed from line to surface. As a result of the diminished presence of the strong lines and edges, the Esprit has evolved into a soft and slippery looking shape. This visual softening has actually contributed to the overall stiffness of the body since the edges no longer act as structural hinges between the planes.



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Aero stability

The revised Esprit comes in three variants; Turbocharged and normally aspirated models for Europe, and a Turbocharged version for American. Basically they all have the same body, but the Cd and CI values vary since the air intakes, rear design and rear lover valance differ from model to model.

Esprit Model

Normally Aspirated: Cd 0.350, Clf 0.089, Clr 0.114
Esprit Turbo Domestic : Cd 0.335, Clf 0.055, Clr 0.075
Esprit Turbo Federal: Cd 0.345, Clf 0.062, Clr 0.091

Turbo variants have a glass panel attached to the of the rear deck forming an extension of the roof, and this is the principal factor that their figures are superior to those of the normally aspirated model. When one considers, however, that the first Esprit had a published Cd of 0.34, the 0.335 figure for the best revised model hardly merits much praise. According to Stevens, however, “The previous Esprit had, in the course of time, been eroded to a Cd of 0.40.” Compare with this, the 0.335 figure represents a some 20 per cent improvement. By that as it may, priority in the development of the new Esprit’s aerodynamic characteristics was given to achieving good aero stability - the aerodynamic stability when wind direction or vehicle attitude changes – rather than the out and out pursuit of a really low Cd. One aim here was to make the Cd and lift less sensitive to pitching though the improvement of areas criticized in the old Esprit.
“Lotus believes that any increase in either front or rear lift as yaw angle increases should be linear and that the front and rear values of Cl should, if possible, remain parallel or converge when represented graphically,” explains Stevens, who goes on to add, “We tool Cl values at 1-degree steps up to a maximum of 15 degrees, since it is possible to have what appears to be a linear graph using 5-degree steps taht actually has a severe swerve in it that is only shown by 1-degree steps.” Stevens and his team spent approximately 250 hours in the MIRA and St. Cyr before they were satisfied.


The new Esprit undergoing testing in the MIRA windtunnel

Interior continues image

At first glance, the interior also strongly resembles that of the old Esprit. The basic composition of the dashboard – a separate instrument binnacle mounted on a slopping fascia, with the switch gear on either side of this – remains unchanged. The binnacle, however, has been designed with a smaller and visually lighter form, while instrumentation is now by V.D.O. The steering wheel on the Turbo has a new 3 spoke design which “we developed jointly with the test driver.” Says Stevens. The normally aspirated version has a 2 spoke design as did the old Esprit. The new binnacle does create a feeling of greater space in the cabin, which, in fact, has 20mm more headroom and 15mm more legroom. The seats are 25mm wider.


Interior rendering drawn by Simon Cox

The revised Esprit could be described as the fruit of accumulated efforts to realize small improvements, and contemporary design techniques. The who expect the redesign of a supercar to produce something more dramatic may well be dissatisfied. The only changes which really stand out are, in the chassis, the switch from a Citroen to Renault transmission and, because of this, the moving of the rear brakes outboard (not on American models), while in the engine department, there is a new water-cooled turbo charger with integral waste-gate. There is little major innovation on the mechanicals either. One wonders whether buyers of this type of car will be satisfied merely with a drastic change in the exterior appearance? There again, from the viewpoint which argues that because it is a supercar, great importance should be attached to tradition and reputation in order to preserve identity, it is desirable, as long as it bears the Esprit name, that it have styling which plainly identifies it as an Esprit. What gives cause for concern with this facelift is the possibility that in some people’s eyes Lotus may appear a conservative manufacturer. This impression, however, is almost certain to be swept away by the totally new Lotus that Stevens and the rest of Lotus Design are working on at present.



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Running Protoype Lotus Esprit X180



Photo of the Lotus Design staff at the London Motor Show, where the new Esprit had its first public debut. From left: Andy Harrison (Trim), Julian Thomson (Exterior), Peter Stevens (Chief Designer) and Simon Cox (Interior).

Thanks to Wayne Barratt for the article