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Just took a trip this weekend with the C6. It was just under 500 miles with about 80% being highway the other 20% split 15/5 between rural highway and city. My C6 now has just over 4000 miles.
I averaged 32.5 mpg from the trip computer and when I filled up today it matched.
On the highway I wasn't pushing it, and ran about 73-75 most of the time. On the rural highway part I was running 55-60 most of the time and the city part was a small town with mostly stop signs.
I was really impressed that a 400hp V8 that runs deep into the 12's can get into the 30's on the highway. Man technology is great.
 

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Tell you what, C6s are very, very impressive. Went to the ALMS race at Laguna Seca over the weekend. Had a Corvette Corral there for Northern California Corvette Owners Association (or something like that).

Man o man, they have 100-120 Vettes. Most were C6s. At least 2 dozen new Z06s. My Dad started shooting the breeze with a guy that looked familiar -- holy crap, that's Dick Guldstrand!

Really good group of people, too. Meanwhile, in the Ferrari corral -- they had a security guard to keep the unwashed like me away. What a bunch of a-holes.

In the meantime, my Dad's 2007 C6 get great mileage -- and is a real hoot to drive with the paddle shift automatic. The shifts aren't as quick as in a Ferrari -- but close enough. And you're not paying anywhere near six figures for it, either.
 

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I suppose the Cd of a Corvette is better than that of a GTO, they are about 500 pounds lighter also. What is the stock rear end gearing, is it the same as the GTO's 3.46?
 

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I am still able to get 27 mpg on the open highway, Yeah 6th gear is wierd at regular highway speeds but it gets you really good mileage
 

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Given the profile of my daily commute:

Sea level - 4100' climb - Sea level, and some traffic on either end of my 230 mile RT daily commute, with an average speed of ~70mph. LA traffic kills the average speed- I drive the majority with cruise control set at 80 but long spurts at ~90+... and I make it a point to go over 100 mph at least once daily (weather permitting) for sanity's sake... :cool

Taking the traffic out of the equation I can average 75-80 mph and still net 21 mpg; but stop - n - go traffic annihilates the average mpg in these cars.

Throwing all of the above into account, I net an average ~19mpg.
 

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Discussion Starter #8
I suppose the Cd of a Corvette is better than that of a GTO, they are about 500 pounds lighter also. What is the stock rear end gearing, is it the same as the GTO's 3.46?
The CD of the C6 is .29. I think the GTO is the same or .30. They are real close, but the frontal area of the Vette is smaller, giving it an aero-advantage.
My C6 is a base 1LT model and it weighs in at 3132 with a 1/4 tank. My GTO weighed in at 3740 with a 1/4 tank, so there is about 600 lbs difference or a 16% advantage.
The gearing on the A6 is completely different than the gearing on the M6. You have a hard time comparing them.

That said the rear gears are 2.56. Here is how it breaks down:

A6 M6 overall ratio A6 M6
1st 4.02 2.97 10.29 10.28
2nd 2.36 2.07 6.04 7.16
3rd 1.53 1.43 3.92 4.95
4th 1.15 1.00 2.94 3.46
5th .85 .71 2.18 2.46
6th .67 .57 1.72 1.97

The first to second spread drops the M6 to 4500 rpms at a redline shift. The A6 with the wider spread goes from 6500 to 3800 rpms. Ideal on the 1-2 shift for a stock LS2 would be 4500 rpms. So the 6m is just about ideal on the 1-2 shift. The 2-3 shift comes up at 4200 for the A6 and 4500 for the M6. The 3-4 puts the A6 at 4800 and the M6 at you guessed it 4500.
If you get your shifts exactly right the M6 is the perfect tranny for the LS2.
As far as fuel mileage goes the A6 is slightly better.
I'm still happy though, the car runs consistant 12.4-12.6 at 114 in the 1/4. I could probably do better every once in a while with a stick, but the A6 is deadly consistant.
My best with the GTO at the track was 12.8 at 109 stock versus the 12.4 at 114. Most of the time I ran 13.0-13.1 with the GTO on a cool day versus 12.5 for the C6. They say every 100 lbs = .1 in the 1/4 and about 1mph, well that is the difference between the 2 cars almost exactly.
The GTO was definately more rewarding due to the difficult nature in driving it to it's potential. The C6 is basically a hit the gas and wake me up when I'm done beating up on the guy next to me car.
 

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I average 14-15 mpg on combination highway / stop and go. I took really easy for a week and got 18.5 mpg. I will take the 14 mpg and keep a smile on my face!:cheers
 

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Right now I am averaging 18.6 according to the computer. This is in 100% L.A. traffic. When I go on a trip I usually set the CC at 80mph and it generally returns around 28-29mpg.
 
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