Mary (Barra): Tadge, even though you don’t sell many cars, you’re hurting our CAFE. And I don’t see this situation getting any better.

Tadge: Waddya mean Mary?

Mary: There’s no way this old-school LT1 engine technology, even with AFM, is going to enable a 40 mpg Corvettes. And we aren’t selling enough Bolts to offset that. You need to at least go to something like a turbo small-displacement V6, preferably with overhead cams with real VVT.

Tadge: But our focus group surveys tell us Corvette buyers like V8s. Moreover, what you are suggesting doesn’t fit gracefully in a C7-type layout.

Mary: What if I give you enough money to finally develop a mid-engine Corvette designed around a dual-turbo OHC V6? Your Corvette fans and buyers will be so distracted, it’ll be easy for you to slide the V6 past them.

Tadge: Now I see why you’re CEO.

 

Prob should head over to the Ford GT forums...I think you're lost

 

I haven't been impressed with the mpg delta b/n twin turbo V6s and LS and LT V8s.

 

I agree. With the way I drive my C6 Z06(mainly highway road trips), gas mileage at 70 MPH is more important than gas mileage at 35 MPH.

My honking 7 liter V8 with 505+ horsepower gets around 15 in the city, but 30+ on the highway. I like that much better than the 3.5 liter V6 with 500 horsepower in the NSX that gets 21 in the city but only 22 on the highway, or the Ford GT that gets 11 in the city and 18 on the highway.

Even the small(4 liter) V8 in the Mercedes AMG GT only gets 16 in the city and 22 on the highway.

The problem with those small engine that use forced induction to get maximum horsepower, is that they run a lower compression ratio. Cruising down the highway at 70 MPH, means they are not in boost, and the lower compression ratio hurts the efficiency of the engine, thus uses more gasoline to cover the same distance as my high compression 7 liter normally aspirated engine.

 

Yet the z06 gets several mpg better than the Ford gt all while making a lot more torque, cheaper to build the engine, less stressed to make the power, will last longer, easier to modify, and sounds worlds better. Ya.... no we can stick to the v8.

 

If the variables are about the same (weight, drag, gearing), then if HP and torque are comparable, using a turbo 4, turbo 6 or N/A 8 doesn't matter much in terms of fuel economy.

 

A 7 liter N/A V8 cruising at 1500 RPM has more torque than a 3.5 liter V6 with forced induction, when running in N/A mode, even when both have the same horsepower at WOT. Usually the gearing of the small 4 cylinder or 6 cylinder or the small 8 cylinder has to be lower to increase the RPM at any given highway speed to run in a higher torque level, thus using more gasoline.

As I have already said, the forced induction low compression small 4 cylinder, 6 cylinder and 8 cylinder engines are not as efficient as a N/A engine with it's high compression ratio and optimized intake manifold runner design.

That is even true in the 6.2 liter C7 GS and the 6.2 liter c7 Z06. The Z06's LT4 is not as efficient when running in N/A mode on the highway as the high compression LT1 in the GS. In addition, compromises have to be made in the intake manifold's runner lengths/shapes that hurt efficiency in the supercharged engine, when it is running in N/A mode. That's why the 6.2L N/A GS gets better gas mileage vs the 6.2L FI Z06.

Your post makes absolutely no sense as it's near impossible to design a car with every thing being identical except for the displacement of the engine.

 

Yeah, those ridiculous car manufacturers doing away with NAs and adopting those inefficient small turbos...
Well, you can't fix stupid...right, Joe?

 

I won't say a V6 Corvette will never happen. But I will say hell would freeze before I buy one. No V8 no care. And I suspect most of the Corvette faithful feel the same.

 

Appears you have all the answers, right, sunsalem?

Tell me then, why does the 647 horsepower Ford GT with it's "efficient" 3.5 liter turbo'd engine, with it's lower weight and it's lower coefficient of drag only gets 11 MPG in the city, and 18 MPG on the highway, yet the "inefficient" C7 Z06 with it's 6.2 Liter 650 horsepower supercharged V8 and it's greater weight and higher aero drag, only gets 15 MPG city, and 22 MPG highway?

Maybe I'm not as smart as you, but you should be able to explain to me why an engine that is only 3 horsepower short of another engine(647 vs 650), doesn't get the same gas mileage, correct, sunsalem?

Gee, less horsepower, less weight and lower Cd and it has poorer fuel economy. That really makes a sound case for the small V6 instead of a large V8, correct, sunsalem?

Why does my 7 L N/A Z06 get the same highway gas mileage(30 MPG) as my 2.3 L supercharged 4 banger Mercedes with it's 185 horsepower? Both weigh 3250 pounds and the Mercedes has a lower coefficient of drag, yet the Mercedes with only 37% of the horsepower of my Z06, doesn't get better gas mileage on the highway.

What do you think would be the gas mileage of my 2.3 liter supercharged 4 banger would be if it were modified to the same 505 horsepower of my N/A Z06? Do you think the gas mileage would stay the same at 30 MPG highway?

 

the European manufacturers are already headed that way, and the japanese and koreanS ditto. not sure how long before the 6's and 4's disappear as all manufacturers turn to ONLY electric AND THE ULTIMATE DOWNER-SELF-DRIVING ELECTRIC CARS!!!!!!!!!!!!!!!!!

we better hang on to our V8 corvettes, because they should be desirable for a long long time. i'm sure many have checked out what a '70's
mopar/hemi is fetching along with all those other glorious engines of that muscle car era.

SAD(as the prez is oft to say)

 

As always, whenever you get emotional, your counters become disingenuous.

You want us to believe your 7.0L C6 Z06 gets better gas mileage than smaller engines...cool.
EXCEPT you conveniently leave out the city mileage ratings.
Lemme help ya with that:
https://en.wikipedia.org/wiki/Chevro...vette_(C6)#Z06

I can even see it might be possible to get "30 mpg," but, of course that would be in the Tremec overdrive 6th gear @ 55 mph.
And good for you if that is how you drive your Z06 too.

I know YOU know the smaller displacement turbos aren't just about better mileage with smaller displacement.
It's also about recapturing exhaust gasses.
NAs spew unburnt gasses into the atmosphere.
It is an enormous waste of fuel.
Turbos recapture a lot of it and redirect it to the ICE to be burned (as ideally it would have been in the first place).

BTW, I recommend Xanax...to take the edge off.
The intellectual dishonesty is difficult to overlook at times.
See your Pharmacist ASAP.

 

Those smaller engines have to work harder to keep up with a bigger displacement V8. Turbos help them perform closer, but add complexity and expense. Then when you add boost to a large displacement V8, well power increases exponentially over that of the little 4cyl or 6cyl.

There isnt a supercar out there that gets the fuel mileage of my stroked 402 with a blower and 3.90 gears. Nor will be as reliable and cost effective long term. And it's 15 year old technology at the very least. The Japanese and Europeans are still playing catch up.

 

Oh my lord, somehow ANOTHER thread (in the C8 section) has become a JoeC5 testimony about the fuel mileage of a C6 Z06. Come on mods, make it stop!!!!

 

Dude, I feel for ya.

Your grasp of math is suspect.
You keep saying you are 75...do you mean 7+5?
I find it doubtful someone who is 75 (unsubstantiated) would spew insults of a 12 year old.
Seriously, get some help...there is nothing wrong or embarrassing about reaching out.

As it is, I'm gonna have to let ya go.
Discussions with you have become a waste of time.
Welcome to my Ignore List.
I bid you adieu.

 

JoesC5 and sunsalem,

Why don't you two get married, take a long honeymoon, and never come back!!!

 

Please stop including personal criticisms in you arguments.

I would like the point of this thread to be: "To what extent will the increasingly onerous CAFE standards affect the C8 design?"

If you think not at all, that's a legitimate opinion.

If you think the C8 will have some characteristics (compromises?) driven by GM overall CAFE, I'd like to hear what you think they might be.

If you think a turbocharged V6 would or would not provide Corvette with a FE benefit relative to current V8 with DI and AFM, don't hesitate to explain your thoughts in that in a civil fashion.

 

I was talking about fuel economy of a large displacement N/A V8 vs a small displacement engine with a turbo.

Since I have a large displacement N/A v8, I used it as an example.

That's perfectly legit. If you want to see what others are getting(gas mileage) and not me, do a search.

For example. here is what Bill Dearborn had to say about the gas mileage with his large displacement N/A V8 in his C6 Z06.

"I did 2368 mile round trip from Endicott, NY to Key West, Fl with a stop on the way for a track day at Sebring. Left on Mar. 27th and got back home 12 days later. Plus additional 800 miles traveled on the Auto Train heading South. Car was comfortable, gas mileage was fantastic averaging over 25 mpg even with a track day and a fair amount of heavy city traffic along the way. On the Interstate at 70 mph it was getting 30 to 32 mpg. Effortless trip, had plenty of room for helmet, cooler, carton of water, baggage for two people, iPad, laptop, extra oil and brake fluid for the track. Heavy coats for northern weather and light rain jackets for southern weather. It all fit.

Bill "

 

Going forward, GM needs to find a way to lighten the Corvette, and then they can dial back HP (achieve the same power to weight ratio) to achieve better fuel economy. That's tough to do in the Corvette's price point because all of US want all the GOODIES (and more!) which, like it or not, add weight. So, now you have to go to exotic materials like Carbon Fiber, but CF is still expensive.
There's not a week that goes by that someone doesn't post asking for blind spot monitoring, lane departure warning, engine start/stop, etc...All this stuff adds weight.

As to what Tadge and company will do going forward, I haven't a clue, but I'm POSITIVE that it will **** off half of Corvette Forum!

 

Joe, what I am saying is there is not much fuel savings with smaller displacement motors, pressurized, over big N/A V8s of the same HP. If you look at EPA fuel economy numbers you will see the composite differences on similar power engines is small--usually less than 10%, and the highway numbers often favor the big V8s because you can hang such a big overdrive on them to lope along the highway.

Have a nice day.