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

[MetroMPG]

Happened across another person with a big block, high torque GM V8 who thinks s/gets better MPG at 80 than 50:

My 6.0L GTO gets me better mpg as I approach 80 or so as compared to 50...lol

It touches 26 almost.

LOL indeed.

From post #17 in this AutoBlog story.

[ALS]

My 6.0L GTO gets me better mpg as I approach 80 or so as compared to 50...lol It touches 26 almost.

Hell I wish my old 1965 GTO with a 389 ci Tri-power (3X2bbl), four speed, with 3.90 gears would have gotten gas mileage like that.

At 50 mph (2500 rpms) with the top down I was thrilled to get 19 mpg.

Probably could have gotten into the low twenties if I was willing to drive at 40mph, (2000 rpms)

[MadisonMPG]

Is the on board computer miscalibrated on cars today? Or are these people making 80mph runs for 5 gallons, filling it up and then making 50mph runs for 5 gallons and filing it up? Or is there no truth to this at all?

[PaleMelanesian]

I see a lot of cases where they say they get XX mpg at 75 mph, but then never say what they get at 55 mph. Makes me wonder if they've even tried, or if they are just spouting the "common wisdom".

[MadisonMPG]

Originally Posted by ALS

Hell I wish my old 1965 GTO with a 389 ci Tri-power (3X2bbl), four speed, with 3.90 gears would have gotten gas mileage like that.

At 50 mph (2500 rpms) with the top down I was thrilled to get 19 mpg.

Probably could have gotten into the low twenties if I was willing to drive at 40mph, (2000 rpms)

That's a lot of info about the car for nothing. haha

Goodness 2.5k @ 50 is 3.75k @ 75.

[elhigh]

Originally Posted by MadisonMPG

That's a lot of info about the car for nothing. haha

Goodness 2.5k @ 50 is 3.75k @ 75.

Geared for the strip, baby. '65 GTO was fitting with 4.11:1 LSD at the factory.

[darcane]

I used to own a '94 Corvette. I didn't use hypermiling techniques, but I was able to achieve 29mpg hwy.

My '94 Vette had significantly less power than the new Z06, and consequently I wasn't able to maintain speed in 6th gear below about 1500rpm. I tended to get the best mileage right at about 60mph because of that (lowest speed I could maintain in top gear). 6th gear in this year Vette is 0.50:1.

High 20's may not be great, but I thought it was for a 5.7L V8 originally designed in the 1950's.

[Formula413]

Originally Posted by MetroMPG

(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".)

As a muscle car enthusiast I have to say that I wholeheartedly agree.

Originally Posted by darcane

I used to own a '94 Corvette. I didn't use hypermiling techniques, but I was able to achieve 29mpg hwy.

High 20's may not be great, but I thought it was for a 5.7L V8 originally designed in the 1950's.

Actually, your 'vette, like my Firebird, had the LT1 engine, also known as the second generation small block. It's based on the original design, but with much more advanced technology. Computerized fuel injection, aluminum heads, optical distributor, etc etc. My 3500 lb Firebird with an auto and 3.23 gears can get 23 mpg highway with this powerplant, I don't think a Gen 1 small block could match that.

[darcane]

Originally Posted by Formula413

Actually, your 'vette, like my Firebird, had the LT1 engine, also known as the second generation small block. It's based on the original design, but with much more advanced technology. Computerized fuel injection, aluminum heads, optical distributor, etc etc. My 3500 lb Firebird with an auto and 3.23 gears can get 23 mpg highway with this powerplant, I don't think a Gen 1 small block could match that.

The differences between a Gen I and Gen II small block are pretty minor. EFI was on the Gen I, aluminum heads are nothing special, and I'm not sure the optispark was an improvement (very common failure point). No, the big difference with Gen II was the reverse cooling. Whoop-di-do...

Don't get me wrong, I really enjoyed that car, but the engine was hardly a leap forward from the Gen I. Now, the LS engines are another story entirely. I've got one in my truck and am absolutely thrilled with it. And it's truly a new generation of engine.

Mike

[MadisonMPG]

The Corvettes 6th gear ratio is something like .56(7):1
I was wondering why you got such good gas mileage.