If I compare like for like, Insignia SE Nav 2.0 CDTi 160 hatch and against a Vectra Elite Nav 1.9 CDTi 150 (Closest on spec) I have found the following.
Insignia 2.0 CDTi 160 Auto SE Nav Auto Gross Vehicle Weight = 2170kg's
Vectra 1.9 CDTi 150 Elite Nav Auto Gross Vehicle Weight = 2030kg's
So the Insignia is 140kg's heavier, so not alot of difference.
Vectra 1.9 CDTi 150 is 147bhp and 235lb/ft
Insignia 2.0 CDTi 160 is 157bhp and 258lb/ft
So the Insignia is 10bhp more and 23lb/ft more than the equivelent Vectra, so is this enough to overcome the 140 extra weight?
Performance and official mpg figures
Insignia 2.0 CDTi 160 Auto SE Nav Auto
0-60 in 9.0 seconds and a Top Speed of134mph (Manual is 8.9 to 60 and 135mph) - So 0.1 difference to 60 between the Auto and the Manual
Vectra 1.9 CDTi 150 Elite Nav Auto
0-60 in 9.4 seconds and a Top Speed of 130mph (Manual is 8.9 to 60 and 135mph) - So a difference of 0.5 seconds between the Auto and the Manual.
Insignia 2.0 CDTi 160 Auto SE Nav
Auto :- Urban MPG = 30.4 - Extra Urban MPG = 54.3MPG - Combined = 42.2MPG
Manual :- Urban MPG = 36.7 - Extra Urban MPG = 60.1MPG - Combined = 48.7MPG
So you lose 6.5mpg by going Auto
Vectra 1.9 CDTi 150 Auto Elite Nav
Auto :- Urban MPG = 29.7 - Extra Urban MPG = 52.3MPG - Combined = 40.9MPG
Manual :- Urban MPG = 38.2 - Extra Urban MPG = 60.1MPG - Combined = 49.6MPG
So you lose 8.7mpg by going Auto
In summary, when you look at the figures, the argument about the Insignia being too heavy and the fact that this weight blunts it's performance compared to the Vectra C is clearly unfounded.
In automatic form, the Insignia 2.0 CDTi 160, although 140kg's heavier than it's Vectra counterpart is quicker and better on fuel than the Vectra by 1.3 mpg.
In Manual form, the Insignia 2.0 CDTi 160 is 2145kg's (Gross Weight) compared to 2005kg's (Gross Weight) of the Vectra, so a difference of the same 140kg's.
So in Manual form, the Insignia 2.0 CDTi 160 has identical 0-60 and top speed times than the Vectra equivalant but is 0.9 mpg worse than the Vectra.
I have found this to be very interesting considering the amount of threads from many people who say the Insignia is too fat and heavy and that the Vectra is lighter and more nimble.
Yes the Vectra is lighter, but the facts show that in automatic form, the Insignia is more efficient than the Vectra, and in manual form, there is pretty much nothing in it.
Any comments welcome.