General Motors‘ top executives make much of the importance of leveraging “vehicle architectures” across the corporation’s vast global product range.

Plans to derive a small Cadillac from the Epilson-based Saab 9-3 are the latest example.

So why did GM choose to develop an all-new architecture for the Pontiac Solstice sports car? Indeed, the lack of discipline leads to doubts about the company’s commitment to cost reduction.

Yet one wonders if GM’s Bob Lutz-led product planners are finally beginning to see the light – that the extra margins earned by successful products far exceed savings from platform sharing.

The Chevrolet Cobalt and Pontiac G6, launched at LA and Detroit respectively, show how GM is implementing its global architecture strategy across its brands. But there are concerns that GM has drifted from this strategy.

The Cobalt is built on the Delta architecture, which also includes the Saturn Ion. But the Pontiac Solstice, in the same size category, required a completely new architecture, called Kappa.

General Motors has reacted quickly to critical acclaim for the Solstice concept shown two years ago. But it could not capture the key qualities of the car using the Delta underpinnings. As a result GM is now seeking other uses for Kappa. The Saturn Curve and Pontiac Nomad concepts shown at the Detroit auto show are two possibilities.

No Compromise Approach

“To get the Solstice right they obviously decided they had to stray off the platform,” says Michael Robinet, a US car market expert with industry analysts CSM Worldwide. “Basing it on Delta could have been easier but GM is taking a no compromise approach.”

GM has already had problems extending the use of Delta to Europe since forming the GM-Fiat alliance. The next generation Astra will use the joint GM/Fiat C-platform. The new 2004 Astra is basically a heavy update of the older GM3000 platform.
The Chevrolet Corvette, a key brand builder, also retains its own platform, the C6. Low ground clearance sports models seem to require their own platform at GM, in contrast with Volkswagen, which bases the highly successful Audi TT on the Golf platform.

The Pontiac G6 does stick with the architecture strategy, sharing the high volume Epsilon platform with the Opel Vectra/Signum, Saab 9-3 and Chevrolet Malibu.

Epsilon disappointments

GM is looking for annual volume of 200,000 units from the G6, but other models on this platform have so far had a disappointing reception. Sales of the Vectra/Signum have not reached predicted volumes and the Malibu has similar problems.

“The interior is not where it needs to be,” said Robinet.

Adding variety to its product line-up is critical to GM’s global competitiveness. While it is not necessarily delivering these new models very efficiently at the moment, increased commonality is a goal of the company.

But with so many brands GM has the most complex task of all OEMs in this area. It will take many more years to deliver the right combination of commonality and product excitement.

Manufacturing processes is a complicating factor. Processes for a low volume vehicle are different from a high volume model. That can justify a different architecture.

When GM decided to develop the Kappa architecture it could instead have modified the Delta platform, said one GM executive. But engineers saw the opportunity to develop other low volume models, such as the Nomad and Curve, off the new platform.

GM was the first carmaker to use a comprehensive platform strategy. Forty years ago it was rebadging the same cars across its American brands. But over time the strategy resulted in a series of uninteresting products  – one of the reasons Japanese carmakers made such huge inroads into GM’s US market share in the 1970s and 1980s.

One of the ingredients of successful companies such as Bmw is a willingness to ignore the parts bin if the concept demands it.

Taking risks with a small sport car may be the wrong way for GM to start. It certainly is contrary to plan. But engineers may have slipped this one past the ‘beancounters’.