Tested: speed vs. MPG, 2008 Corvette Z06 (505 hp)

[NiHaoMike]

Did P&G help, hurt, or have no effect?

[jamesqf]

Originally Posted by ALS

exception to the rule. What did a four cylinder Regal, Celebrity, Taurus, K-Car or even a Plymouth Horizon get?

As I said earlier, different worlds. Did anyone actually buy American cars back then? The CRX was probably the mpg champ, or close, but the Honda Civics & similar of that era got in the 30s. Heck, I get over 25 mpg from my '88 Toyota pickup, which is 4WD, and usually driven on roads where 4WD is needed, and/or hauling loads of firewood &c.

[SentraSE-R]

I have a pretty good recollection of road trip mileage on my cars. All thrashed to 7 mph above the speed limit before I hypermiled.

1959 Buick Electra (364 cu in) - 12 mpg
1963 Rambler American 220 - 25 mpg
1970 Datsun pickup - 25 mpg
1977 IH Scout II 4X4 (302 cu in) - 11 mpg
1976 Datsun B210 - 36 mpg
1983 Nissan Sentra wagon - 35-45 mpg
1987 AMC GTA - 36 mpg
1987 Chevy Astro (4.3 L) - 15-17 mpg (22 mpg @ 55 mph)
1996 Nissan Sentra SE-R - 36 mpg
2002 Nissan Sentra SE-R - 26 mpg (43 mpg hypermiling)
2006 Scion xB - 32 mpg (45-59 mpg hypermiling)

[MetroMPG]

Originally Posted by NiHaoMike

Did P&G help, hurt, or have no effect?

Unfortunately, we didn't do any P&G comparison runs - spent nearly 2 hours just getting the steady state data.

[MetroMPG]

I've updated Post 1 at the top of this thread with this graph of the results, plus methodology & raw numbers.

[MetroMPG]

Interesting: I just looked up the Corvette Z06's fuel EPA economy rating:

Model 1 Vehicle Characteristics

It's 15 mpg (US) city / 24 mpg (US) highway / 18 mpg (US) combined

No wonder the British guy was able to win his competition on % over the government rating.

Extend the graph, and this car "meets" its EPA highway rating at 130+ km/h / 80+ mph! (Steady state, level road, etc.)

That's astounding. In stock form, my car's "EPA highway" speed was below 100 km/h / 60 mph.

[jcp123]

Originally Posted by MetroMPG

I suppose "very good highway mileage" is a relative thing, eh?

Depends where you're coming from.

I got one tank that was approaching 21mpg in my Mustang and I was elated

[Mustang Dave]

Thanks for posting this, MetroMPG.
That speed vs. MPG graph pretty much mirrors my experience with my Mustang. Most performance car enthusiasts ass-u-me performance cars have a "sweet spot" around 75 MPH. That just ain't so with modern (efficient) fuel injection systems. In my experience, the best FE is at the lowest speed in your top gear. In my case, about 35-40 MPH.
And it's interesting that most people can't believe that a performance car can get fuel "economy".
According to EPA's 2008 estimates, I should be getting 17 City/ 25 Highway/ 20 Combined with my Mustang.
The worst I've ever gotten was .02 MPG under EPA Highway. (24.98) And that was because I ran it in the garage to charge the battery (at ZERO MPG) during the Winter.
According to ecomodder.com's criteria, I've never not been a hypermiler with my Mustang.
I'm getting better fuel economy with my Mustang than a lot of people get with their 4-cylinder Camrys and Altimas.
A major part of it is the "nut behind the wheel" and route planning.
As they say, YMMV.

[MetroMPG]

Originally Posted by Mustang Dave

Most performance car enthusiasts ass-u-me performance cars have a "sweet spot" around 75 MPH.

I've seen statements to that effect so many times I was beginning to wonder if maybe it was true.

My relative lack of experience with big displacement, high torque engines (with the single exception of my first car - in which I never paid attention to fuel consumption) had me doubting common sense.

Not any more!

(PS - my Firefly is a "performance car" of a different kind - high efficiency is high performance! I don't like that "fast" = the only kind of "performance".)

[instarx]

But wait. You said the ScanGauge wasn't calibrated to the corvette. Doesn't that mean that those MPG figures you posted don't mean anything? Without calibration don't the scanguauge readings simply show the relationship between mileage and speed, and not actual MPG? I don't have or use a scanguage so maybe I just don't understand how it interacts with the car.