They get amazing gas mileage. Wife and I went for a lengthy spin this morning and gas gauge didn’t move a whole lot. Even made the comment to her that had we been in our '69 Camaro, it would have emptied half the tank and still doesn't perform anywhere near the level that our Z51 does. Amazing cars these C7s are.

On edit: I didn't buy it for gas mileage, but it is icing on the cake...

 

Never ever Have I come close to 33mpg w/o ECO. Are you really driving at 70? Please tell me your average speed was less then 70. I don't want to be critical, I just want to make sure there is nothing wrong with my car or driving!

I consider my self a good driver but depending on the speed limit and traffic conditions, I will run on average 75-80+ mph on the FL turnpike (Stay under 10mph over limit), 7th gear, seldom have a need to down shift, and no ECO. I generally stay in my lane, using the left lane to pass and never get closer then 4 car lengths to the car in front of me. The best I ever got was 24mpg w/o ECO during a round trip to Disney with minimal local driving (23.85 MPG = 435.6 miles / 18.266 Gal The car computed 23.0 mpg Actual better by 3.8%)

Do I have something to worry about? I always thought the new cars were optimized for 55 -60 mph and in the case of the Vette; ECO to get better then 30mpg?

 

Never ever Have I come close to 33mpg w/o ECO. Are you really driving at 70? Please tell me your average speed was less then 70. I don't want to be critical, I just want to make sure there is nothing wrong with my car or driving!

I consider my self a good driver but depending on the speed limit and traffic conditions, I will run on average 75-80+ mph on the FL turnpike (Stay under 10mph over limit), 7th gear, seldom have a need to down shift, and no ECO. I generally stay in my lane, using the left lane to pass and never get closer then 4 car lengths to the car in front of me. The best I ever got was 24mpg w/o ECO during a round trip to Disney with minimal local driving (23.85 MPG = 435.6 miles / 18.266 Gal The car computed 23.0 mpg Actual better by 3.8%)
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The photo in the original post above is from the first leg of the trip on I 71. Speed limit is 70 and I kept it at 72-74, did have a couple of traffic slowdowns near Columbus. Also had traffic slowdowns near Cincinnati and I 71 to I 65 South interchange so they lowered the Avg. speed but the fill up represents the overall mileage. I do combo city / hiway and typically show 24-26 average there. The 7th ratio on non Z51 is .42:1 and I believe Z51 7th is .46:1 giving a small advantage to non Z51 although the*larger tire size might (?) mitigate that*. You mileage does seem a bit low based on my experience and other comments here.

*My non Z51 goes exactly 1200 RPM@65 mph, what does your Z51 turn at 65?*

 

I have found that I get 30+ MPG on the highway without being in 4 cylinder mode and driving >70mph [emoji41]

 

I do as well!

This was on a trip last year and included highway speeds, as well as city and road construction. Running between 75 - 85 on the highway.

 

Our Z06 runs 24-25 mostly on the highway. Have gotten 28.5 on a long trip,6+ hours, driving hard.

 

I'm totally amazed at the fuel mileage I get with my base A8. I have posted in the past shots of my panel showing over 35 mpg over a 300 mile period and averaging 62 mph. I believe a portion of that was on Florida 301 which has many lights and speed zones.
I doubt if my Grand Sport on order will achieve that mileage because it has the larger drag inducing spoiler than my base. Was not able to order it with just the small center one.
On the highway I have no problem going 500 miles to a tank with reserves.

 

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I don't have a spoiler, I wonder if it has much impact on air drag? It seems to me it might increase drag slightly......
I almost always used cruise / Touring mode / had NPP closed......don't know if NPP open makes any mpg difference?

Returning from Bowling Green, heading North approaching Columbus Ohio

 

Similar results for me:

 

Seems that i am a bad ass driver i get only about 15-20 miles on my z06 .lol

 

That's the price you pay for being able to brag about the extra 200 horsepower you'll probably never use.

Just the fact that the engine is driving the supercharger is fuel consuming drag especially at cruising speeds when you don't need any boost. Other factors such as final drive ratio and transmission choice affect mileage too.
That is why the Grand Sport is going to be so popular.

But, as many have said previously, " they don't care, if you have to ask how much............. ".

 

Only have 1500mi total. Might my score will improove a bit over time . I am always in v8 mode sport or touring

 

Well, I have been able to get 29 from my Z06 for some open road driving. However, if you factor city driving into the equation, that does come down significantly.

 

I average 16.5 mpg lol

 

I've been averaging about 15.6.

 

The VW Beetle of the early 1960s had 40 horsepower and fuel economy (in the days of 30 cent a gallon regular) was a major selling point. Yet that car only got around 27 mpg.

Our Corvettes are wonderful "economy cars".

 

My 2106 Z06 is about the same thing.. 24-26 HWY.. City 19-21
Had 2014 C7 it would consistently average 30+ on HWY.

 

I don't have any pictures of the DIC but my estimate is that I get 19-24 on the highway in Tour at 72mph, but in-town the average is about 14-17 in Sport Mode.

 

My mileage is pretty good.

 

I picked up the car at the museum,a LT1, and drove to central Florida got around 33 , doing 65, 70 , sometimes I was in Eco mode .

 

Z51 equipped manual cars will likely see slightly less mpg than a non-Z51 car due to the shorter transmission ratios and rear end gearing. The larger Z51 spoiler will also create a touch more drag than the smaller base spoiler. However, I doubt the difference would be more than a mile or two per gallon. Also, in cerain circustances, 6th gear will actually yeild better mpg than 7th while in Eco mode, as it allows the engine to stay in 4 cylinder mode more. And there are conditions where staying in V8 mode will get you better mileage, such as in hilly terrain. I've found the mileage "sweet spot" to be in the 1400-1700 rpm range, regardless of speed. I've had a 50-mile averege of 39mpg, all highway.

 

The answer to this question is solely dependent on how you drive and where you drive. I have many C7 friends who live in cities and suburbs, who are not lead-footed, yet get below the advertised C7 mileage (traffic, stop-n-go and many red lights), and others who are lead-footed (their description) who live in the wide open spaces who also get below GM's advertised mileage amounts.

I live in the wide open spaces, do a large amount of interstate and curvy-country-road driving, and just got 23.1 MPG on our 4,544 road trip, have averaged 21.3 MPG in our first 13,000 miles -- in our C7 Z06. And as people who drive with me know, we really haul the mail when safe to do so.

Thinking back over three years of posts on C7 mileage posts, there are tons of SRF members whose mileage exceeds GM estimates for our C7's.

 

I just got back from a 1500 mile journey. Mostly free way miles cruising in 7th between 70-80 miles per hour. I also did maybe 50 miles of city driving. The average mileage I got for the trip was exactly 25 mpg.

 

I actually get my best mileage cruising in 6th. I seldom use 7th unless I'm cruising above 85 mph, which again is uh, seldom.

 

Are you in Eco mode in 6th? I was in sport mode the entire time.

 

I was going to ask the the same Question.... My z51 says to use 1-4 gears in Eco mode. Was curious if people are getting better using higher gears.

 

I came across an article in Popular Mechanics on using ECO in the C7.

They were able to average 37.3 MPG over a 124.7 mile drive in CA, with an average speed of 53 MPH. The author believes that 40 MPG is achievable with hypermilling.

"As I pulled up to the same pump at which I had initially filled the Corvette, the trip computer showed that I had traveled 124.7 miles at an average speed of 53 mph and consumed fuel at the rate of 34.0 mpg. Impressive... So I filled up the new Corvette; it took only 3.34 gallons to refuel the C7 after the trip. That's a stunning 37.3 mpg over that course... This is hardly a definitive test; it's a simple, back-of-the-envelope evaluation. And an experienced hypermiler using every trick in the book could easily top it–I'd guess they could achieve 40 mpg on the same route. "
Hypermiling the C7 - Taking the 2014 Chevy Corvette on a Fuel-Economy Run

I liked the authors closing paragraph:
"All of this reinforces what I learned five years ago. First, that conservative driving pays off in significantly reduced fuel consumption. Second, that the Corvette remains a singular achievement in the history of sports cars, mixing overwhelming performance and economy in a way no other sports car even approaches. And third, that driving a Corvette under cruise control at 55 mph is booooring."

 

While its an interesting exercise to see, out of curiosity, how many miles one can squeeze out of a gallon with a C7, why would anyone buy this car and want to drive that way? Its like buying a top of the line personal computer, then using it to play Pong or run Basic programs.

I get an honest 22 to 27 mpg on my hilly, curvy two lane roads with throttle blips and fast passes of slower cars where appropriate. And I don't use AFM. I can find 93 octane premium up here for $2.369 a gallon.

When I want to hypermile, I use my "cheater" VW diesel TDI.

 

My 2014 Z-51 is my daily driver. Close to 20,000 miles now at an average of 19 MPG over the life of ownership mostly in stop-and-go city traffic. I regularly get 29-30 MPG on road trips. And yes, I pretty regularly push the right pedal pretty hard because its just fun to do.....

 

Close to 7000 miles on a cross country trip produced 27.1 average mpg as shown on the DIC. This is good as most of the trip was on secondary roads through many towns. About 1000 of the miles were logged in the city of Seattle under 40 mph. I view the 27.1 as the best of any vehicle ever owned by me. If I drove on an interstate at 60 locked in cruise I imagine the results would be well over 30 mpg. I really like the performance. Charlie aka cutnout

 

John, unless you have some sort of Mad Max blower with a clutch, your supercharger is always turning. It's always taking some power to run it. It doesn't care if it's in V4 mode or not. When you're not in boost, it's a small penalty .

At full tilt boogie, it's probably taking 100 Hp just to run the supercharger... (meaning if the car makes 650 Hp, it's actually making 750+ to do that.)

 

I don't own a Z06, but like most of us I'm impressed by the LT4 engine. You brought up some points about supercharging that I hadn't thought about, so I did a little digging on how the LT4 supercharger operates. Here are come interesting details:
- The charge air bypass valve is a vacuum/electrically operated solenoid valve that is attached to the supercharger housing. The three-way valve is controlled by the engine control module(ECM). The ECM determines when pressure from the manifold is routed to the bypass actuator. The charge air bypass valve allows pressure from the manifold to open the bypass valve and lower boost pressure during specific driving conditions. The open bypass valve reduces the pumping effort of the supercharger, thereby increasing the fuel efficiency in light load operations. So, the supercharger only comes on when the engine computer determines there is a demand for it, otherwise, it is bypassed. Drivers cannot force it on or off.
- I haven't been able to find any published power requirements for the LT4's supercharger, but the aftermarket does publish their numbers. Two aftermarket blowers have power requirements of 48-69 HP. Callaway also describes their custom C6 unit, "Callaway's version of Magnuson Products' popular MagnaCharger is said to deliver more horsepower per psi of boost than any other supercharger system. Power increases greater than 150 hp in a C6 (120 hp in a C5) can be realized, thanks to Callaway's new inlet design, which increases airflow for improved efficiency. An internal bypass valve minimizes parasitic loss, meaning less than 1.3 hp is required to turn the supercharger at 60 mph."

So, while we haven't seen numbers published for the power requirements for the LT4's supercharger, it's power requirements off-boost are likely quite low.

 

The best long distance average I have gotten with my Z06 (2016, A8, never in V4 mode) was 26.2 running around 80 MPH for most of the trip from E. TN back to IL earlier this summer. There were a few slowdowns and a couple of stops for fuel and food but the MPH average was right at 80 MPH because I exceeded that speed quite often.

The power to turn the Z06 supercharger off boost is very little and has an insignificant impact on mileage. The Z06 lower mileage is largely due to the lower base compression ratio of the LT-4 compared to the LT-1, greater wind resistance from the wider body and tires and the aero components tuned for additional downforce, and the rolling resistance of the wider tires is also greater.