Lotus takes a brave line on Evora

  • 08-Dec-2011 04:59 EST
Lotus11-11Evora MY12_2.jpg

Lotus benchmarked the MY12 Evora against the Porsche Cayman. Lotus boss Dany Bahar believes the Evora is now equal to it, or better, in terms of overall package.

Automotive design, engineering, and production must be based on a philosophy of continuous improvement; without it, the industry and all its constituent companies would ultimately fail.

So, year after year, new or modified technologies, models, and manufacturing techniques are introduced. These may involve a thoroughly novel approach or entirely new systems but often are just an evolution of what went before. That may be because last year’s product was underdeveloped or simply unsuccessful, but invariably a spin is put on the reality and no reference is made to what may have been anything from a financial disaster to mildly disappointing sales and disgruntled buyers.

But now Lotus has broken away from all this and has said, bluntly, that the Evora, introduced in 2008, really wasn’t good enough, that all criticism had been evaluated, major efforts had been made to put things right, and that the 2012MY Evora is a car that is much better.

Lotus is even sufficiently brave to list what it agrees was wrong with the first-generation Evora. Very few companies will do that.

“We benchmark the car against the Porsche Cayman, and I think in terms of overall package quality the Evora was originally 30% to 40% below it," said Group Lotus CEO Dany Bahar. "Today, with the latest Evora, I would say we are up there with the Cayman—if not better—and we have a confidence we never had before.”

Bahar—who has overseen the quality and manufacturing improvements since his arrival from Ferrari in October 2009—together with Lotus’s executive team have publicly highlighted a raft of shortcomings on the original car, some of them relatively major, some so minor that they hardly seem worth mentioning.

But Lotus has mentioned them—and in some detail, with around 140 items fixed.

The company listened to what customers and journalists have said about the Evora since its launch and has addressed most of the issues. Mechanically, these cover gearshift dynamics, engine character and response, and suspension details. Other significant areas addressed are the interior perception and driver environment including HMI (human machine interface) effectiveness.

The linking of those items is said to be significant enhancements to overall quality while improving manufacturing efficiency, with build time down from around 260 hours per vehicle to less than 200. The manufacturing defect rate has been cut by more than 70%, claims the company.

Details of the gearshift improvements include internal gearbox revisions; the use of low friction, high-quality selection cables; a low-inertia flywheel (reduced 46%) to improve engine response; a low-inertia clutch (reduced by 36%) to allow the gearbox synchronizers to slow down in a shorter time, so reducing shift times across the rev range; and revised engine mounting stiffness using additional 50 kg/m³ (3.1 lb/ft³) snubbers to improve driveability and engine response.

Engine calibration and a new exhaust system have been modified to counter criticism of lack of the “right” engine sound for a high-performance sports car. The exhaust has a bespoke internal system; the engine protection valve opens above 4700 rpm, changing the flow of gases and increasing the volume. A driver-operated Sport button operates the valve on what Lotus terms a “more aggressive” opening strategy for optimized sound.

Chassis changes include a 15% increase in wishbone bush stiffness on the rear axle and one location on the front axle; rear anti-roll bar increased by 0.5 mm (0.02 in); and revised static suspension geometry.

The interior of the Evora, which was, for its price bracket, unmemorable, has been significantly upgraded with higher quality materials; a change in adhesive; more and thicker stitching; use of high-density foam scrim; plus generally upgraded facilities and equipment. The steering wheel has been “updated,” the gear shift lever’s height increased, and a new infotainment system fitted.

Some instruments have been a point of criticism on the Evora although these will take longer to improve, says Lotus.

The company has also invested in staff training and process methodology to improve overall quality and manufacturing efficiency.

“Outsourcing trim would bring build time down by a further 25 hours to 175,” says Michael O. Och, Lotus’ Director of Operations, who previously worked for Porsche and has played a central role in changes on the Evora production line. “But we are keeping that in-house with a new trim shop because our people are very good at what they do. We have given them new tools, which allows them to match any outsourced solution at a competitive cost and we have constant quality control.”

If Lotus did go for maximum outsourcing, Evora build time could drop to about 150 hours, he said, but the cost/benefit ratio, particularly in terms of whole vehicle quality, would not be convincing, believes Och.

Five new Lotus models are in the pipeline, and Och is working closely with design and development teams with regard to more efficient assembly. Combined with the added use of more externally sourced modules and the introduction of conveyor systems, Lotus’ build times of future products are likely to come down further—possibly to less than 100 hours per unit with an improvement in quality, he believes.

Och rotates manufacturing personnel annually so they gain experience in different areas of production: “When working too long in one area, you don’t always see things that are wrong; moving to a new task brings a fresh pair of eyes to the job.”

Quality inspection has been moved from within the line to end of line. Och has also introduced fundamental improvements to manufacturing facilities, such as better lighting and general upgrades to buildings, some of which go back to World War II when the Lotus site was a U.S. Army Air Force (USAAF) base operating B-24 Liberator bombers.

“The basic thing about achieving quality, though, is the thorough design and development of a new model and the suppliers used,” explained Och. “As a specialist company, we build about 1200 Evoras a year, which is a very small number for some suppliers and they may not wish to work with us. So sometimes we may need to use very small companies, but they, too, provide the high quality we demand—although they may just employ nine people and a guard dog!”

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