Gavinfdavies
Member
Some updates on where to buy new bits and what they should look like:
The 2.4 throttle body is 65mm (2 9/16 inches) and has the plug on top, part number is 12580195.
The 2.0 supercharger tb (Which apparently you should avoid) is 68mm (2 11/16 inches) and has the plug underneath and also a brass probe, part number 12565553.
The optimum 2.4 inlet manifold with the fat square runners with no external webbing is part number 12587878.
Regarding the later, it was about this time (2005 on) that GM swapped from a lost core plastic casting method for their intakes (High quality but expensive) such as the excellent LS6 intake on Corvettes, to a multi-peice injection moulding that are vibration friction welded together. This is much cheaper but lower quality: The welds are weak and often leak small amounts of air, plus need large areas for joins since you need to garantee the flexible plastic will line up each time, an issue that an expensive single casting doesn't have. when comparing the fat summer 06-07 manifold to the 08-on item, I strongly suspect that is the reason for the visual and performance differences.
The 2.4 throttle body is 65mm (2 9/16 inches) and has the plug on top, part number is 12580195.
The 2.0 supercharger tb (Which apparently you should avoid) is 68mm (2 11/16 inches) and has the plug underneath and also a brass probe, part number 12565553.
The optimum 2.4 inlet manifold with the fat square runners with no external webbing is part number 12587878.
Regarding the later, it was about this time (2005 on) that GM swapped from a lost core plastic casting method for their intakes (High quality but expensive) such as the excellent LS6 intake on Corvettes, to a multi-peice injection moulding that are vibration friction welded together. This is much cheaper but lower quality: The welds are weak and often leak small amounts of air, plus need large areas for joins since you need to garantee the flexible plastic will line up each time, an issue that an expensive single casting doesn't have. when comparing the fat summer 06-07 manifold to the 08-on item, I strongly suspect that is the reason for the visual and performance differences.
