GM Theta platform

Infobox Automobile platform
name = GM Theta platform
manufacturer = General Motors
production = 2002–present
class = Compact/mid-size crossover SUV
vehicles = Chevrolet Equinox
Pontiac Torrent
Saturn Vue
Suzuki XL-7
GMC Terrain
Saab 9-4X

Theta is General Motors' mid-size crossover SUV and compact SUV automobile platform. The architecture debuted in 2002 with the Saturn Vue (Theta, compact SUV) and was later used for the Chevrolet Equinox (Extended Theta, mid-size crossover SUV). The platform was developed by GM in North America. The Saturn was engineered in Michigan and the Equinox/Torrent were engineered by GM's Canadian Regional Engineering Center (CREC) in Oshawa, Ontario. Neither Suzuki nor GM's Shanghai, China operation, Pan-Asia Technical Automotive Center has had involvement in engineering or developing the Theta platform.

Development

The Theta uses a four wheel independent suspension. Engine choices include the Ecotec Family II straight-4, "3400" V6, and even a Honda V6, the L66. A 5-speed automatic and two 5-speed manual transmissions are used.

The original Saturn Vue used a short 106.6 in (2708 mm) wheelbase, with a 61 in (1549 mm) track. The Chevrolet Equinox and Pontiac Torrent use a stretched 112.5 in (2857 mm) wheelbase, but shares much with the Saturn.

The Suzuki Grand Vitara, although similar in size and appearance to a Saturn Vue, was developed by Suzuki using some Theta components, but should not be considered a Theta derivative. The Grand Vitara front and rear suspensions are substantially different from the Theta vehicles. The 2007 Suzuki XL7 is based on the Theta platform and is built alongside the Equinox and Torrent at CAMI Automotive in Ingersoll, Ontario, Canada. It is the first non-GM branded vehicle to come off the Theta platform. Styled by Suzuki, the engineering was performed by GM engineers in the US and Canada.

Engineering for the Opel Antara, Chevrolet Captiva, and the Saturn Vue was performed in large part in Korea by GM Daewoo Auto & Technology.

Hybrids

The Saturn Vue was one of the first of General Motors' vehicles to be offered with a hybrid powertrain, GM's belt alternator starter (BAS) system, in 2006. The company also plans to add hybrid versions of the Chevrolet Captiva and Vauxhall/Opel Antara, but those will use GM's Two-Mode Hybrid system instead of the BAS.

Vehicles

Current vehicles based on this platform:
* Short wheelbase
** 2002 Saturn Vue
** 2007 Daewoo Winstorm
** 2007 Opel Antara and 2008 Saturn VUE.

* Long wheelbase
** 2005 Chevrolet Equinox
** 2006 Pontiac Torrent
** 2007 Suzuki XL7
** 2010 GMC Terrain
** 2010 Chevrolet Equinox

*Concepts
** Chevrolet S3X/T2X

Theta Premium

GM is preparing a premium version of Theta. Reports differ, but the general consensus is that it is a combination of the current Theta and elements of the new Epsilon 2 architecture, with some Lambda components as well. So far, the only models are the Saab 9-4X and Cadillac SRX. Despite the fact that these vehicles are loosely based on Theta, which is often used for small CUVs, it is believed that these will actually be midsized, since many have predicted that the 9-4X replace the similarly sized Saab 9-7X. There are also rumors of 7-seater TE (Theta-Epsilon) models under development.

Vehicles using Theta Premium:
* 2010 Saab 9-4X
* 2010 Cadillac SRX

References