I did a search and only found the outside diameter, and see people with ported TBs having 60 or 62mm inner diameters.
What is the stock inner diameter?
My wife's 2003 Ecotec 2.2 liter Sunfire:
* 2 1/4 inch turbo muffler
* 2 1/4 piping to a 2 1/2 inch resonator
* 2 1/4 inch catalytic converter
* 2 1/2 inch down-pipe
* a match ported 4:2:1 RK Sports 'clone' header
* an AEM true cold air intake NOPI edition
* 8 gauge ground wire kit
* Toyz front strut brace
* Vibrant rear strut brace
* and Russell stainless steel brake lines all around.
It must be 58mm, only because MRZ has bored TBs of 60 and 62mm.
Unless the 60mm inner diameter is retained and they bore elsewhere.
My wife's 2003 Ecotec 2.2 liter Sunfire:
* 2 1/4 inch turbo muffler
* 2 1/4 piping to a 2 1/2 inch resonator
* 2 1/4 inch catalytic converter
* 2 1/2 inch down-pipe
* a match ported 4:2:1 RK Sports 'clone' header
* an AEM true cold air intake NOPI edition
* 8 gauge ground wire kit
* Toyz front strut brace
* Vibrant rear strut brace
* and Russell stainless steel brake lines all around.
I've measured 3 ecotec tb's, all 60mm, no less than 59 mm (including the tb off my car)
The throttle plate I got out of the junkyard from an eco is 57mm.
