GM Sigma platform

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Sigma is General Motors' new mid-size rear-wheel drive automobile platform. The architecture debuted in 2002 with the 2003 Cadillac CTS and is adaptable for all-wheel drive and extended wheelbase versions. Development of the Sigma platform began at Holden in Australia before 1998 as GWRD or Global World Rear Drive.

The long-wheelbase Cadillac STS replaced the front-wheel drive GM K platform Cadillac Seville. The CTS was a replacement for the rear-wheel drive Cadillac Catera.

The Sigma platform has a four-wheel independent suspension with control arms in front and multi-link in the rear. GM's High Feature V6 and Northstar V8 are most common, though the small-block V8 has also been used. GM's 5-speed 5L40/5L50 automatic transmission is used throughout the range.

All Sigma vehicles are built at the purpose-built Lansing Grand River factory in Lansing, Michigan.

1 Vehicles
2 Sigma II
3 Sigma Lite
4 See also

[edit] Vehicles

Current vehicles based on this platform:

Future vehicles using this platform:

2008 CTS
2009 STS

Sigma II will debut with the 2008 CTS which will be larger and wider than its current counterpart it will share more parts with the larger Sigma I than the smaller Sigma I. Sigma II will be more flexible and will feature the new Direct Injection 3.6 HF V6 as its primary engine, the 2.8 HF may receive DI and would likely power the European Sigma cars. Sigma will stay a Cadillac exclusive.

[edit] Sigma II

The 2008 CTS will be the first model to ride on Sigma II, an improved version of the Sigma platform. It will be larger than the current model, and use the current 3.6L HF V6 and a new more powerful 3.6L DI HF V6, as well as a possible Ultra V8 powered version. It will debut at the North American International Auto Show

For 2008 a moderately updated SRX with new interior and slight grill changes will debut. A Sigma II version would not be out until 2010 or later. The same holds true for the STS at the same time.

[edit] Sigma Lite

A so-called "Sigma Lite" variant might reach production in 2007 as a replacement for the reworked Zeta platform. These vehicles would be built with less-expensive components and would be sold by Buick, Chevrolet and Pontiac.

The name Sigma Lite has been out of use for some time. The chassis is internally referred to as Global Volume RWD, though it is AWD capable. It is also referred to as Zeta II or simply Zeta as the original Zeta plan was killed some time ago. There will be different versions of this chassis produced all over the world. It will replace the Holden VE architecture after about 5 years. The first Global Volume RWD will be either the 2009 Chevrolet Impala or 2009 Chevrolet Camaro. Both will feature a double pivot McPhearson front strut suspension, modified from Holden's VE, and an independent rear suspension system very similar to that of Sigma II but using cheaper steel rather than aluminum to save cost. Expect GM to use the 3.6 L HF V6 across the board with these vehicles as well as the current V8 out when they reach production.