Re: (estimated) top speed
Just for kicks and giggles, I decided to figure up what the top speed would be with no governor. I used these figures, taken from Autoblog:
Gear Ratio

1)
First: 4.48
Second: 2.87
Third: 1.80
Fourth: 1.47
Fifth: 1.0
Sixth: 0.742
Reverse: 2.88
Final drive ratio: 3.16 (FWD / AWD) 2.73 (FWD)
I used the 3.16 ratio for the calculations
Wheel size and type:
18 x 7.5-in; cast aluminum (std)
19 x 8-in; cast aluminum (opt)
Tire size and type:
P255/65R18 ALS blackwall (std)
Tire diameter = 31.05 inches
P255/60R19 AL3 blackwall (opt)
Tire diameter = 31.04 inches
It doesn't matter which tire size you use since there is only a 0.01 inch difference in total diameter, not enough to affect the results
Source:
http://www.autoblog.com/2006/07/12/2007-gmc-acadia-revealed/
Now for the fun part. I used this online gear ratio calculator:
http://www.xse.com/leres/ss/calculator.html
I verified the results against another two others as well. All MPH figures are rounded to the nearest whole number.
1st gear @ 6500 RPM - 42 MPH
2nd gear @ 6500 RPM - 66 MPH
3rd gear @ 6500 RPM - 106 MPH
4th gear @ 6500 RPM - 129 MPH
5th gear @ 6500 RPM - 190 MPH
6th gear @ 6500 RPM - 256 MPH
These results do not exactly jive with sandman's figures from Car and Driver. Anyone have any idea why? I am guessing that one would arrive at the figures from C&D after figuring in inherent loss due to it being an automatic transmission, but this is one area of cars that I do not know as much about as I'd like. Feel free to double check my figures, and if anyone knows something I don't that would explain these discrepancies, please enlighten me. ;D