Quite true, it's amazing that such myths are still propogated. The biggest factors in a vehicle's mileage are its weight and aerodynamics. With modern combustion control a large engine does get not significantly worse mileage in an identical car. And yes there's a bit more friction in a V8 vs. a 4 banger, but in GM's case the V8 has one less cam and an equal number of valves compared to the 4 cylinder, so it's not like it's a 50% difference.

As to gas prices, it seems that people have awfully short memories. Many have a difficult time fathoming a scenario different than what they see today, as if world events will never ever change course. Look back to the late-70 and early 80s. Motorists were facing actual gasoline shortages, not just high prices. At the time, no one on the face of the earth would have predicted we'd ever see oil at $15 a barrel, yet that happened in the 90s and we enjoyed cheap oil for most of the decade. So don't assume because oil is currently (relatively) expensive, that it will never get cheap again.

 

I don't know how much friction comes from the pistons and how much comes from the camshafts spinning, but AFM doesn't help with piston ring friction. I agree that a smaller number of camshafts helps, but then you have more valvetrain mass to accelerate back and forth with a pushrod configuration.

Also, as seems to be the case with hybrids, the AFM seems to help more in the EPA test than in the real world.

Don't get me wrong. I like the V8s too (I own one). But a smaller car with a 4 cyl will get better mileage.

 

We also shouldn't minimize the relationship between vehicle weight and engine power. A more powerful engine requires heavier components.

The Corvette and Miata are both examples of cars that have been optimized in weight for there various powertrains. The Miata weighs about 800 pounds less than the convertible Corvette.

So it's not simply a matter of substituting a 4 cyl engine in a vehicle designed to take a V8.

 

I agree with the above....V8's do not mean terrible MPG. I'm sure that when you crank up the boost on the GXP (example given above), the mileage is close to an LS2 under hard acceleration. I am very happy with the MPG I get with my LS2....especially after I tuned it.

 

O Rly?

 

2006 Pontiac Solstice 2.4L I4 cyl 5spd man. EPA fuel economy 20 City 28 Hi.
2002 Pontiac Trans Am 5.7L V8 6 spd man. EPA fuel economy 19 City 28 Hi.
Think I lie? See it here http://www.fueleconomy.gov/

And the Firebird is 600lbs heavier...
I'll take the 175 extra HP and torque in exchange for the tremendous fuel economy penalty...

 

And the 2.0T GXP/Redline models get better mileage than the base models. GM must have some advanced physicists working on hyperdrive to get their hi-po motors to get as good or better mileage than their smaller, slower ones!

 

When cancelled, the GTO was scheduled for 2008.

http://www.detnews.com/2005/autosins...A01-123402.htm
http://www.cnn.com/2005/AUTOS/07/29/new_gto/


http://web.camaross.com/forums/showt...to#post3583111
http://web.camaross.com/forums/showt...A01-123402.htm
http://web.camaross.com/forums/showt...to#post3133906


You didn't start backing away from 2008 timeframe till the start of last year:

http://web.camaross.com/forums/showt...to#post3674538 (post #8)

Whatever may or may not have happened since then, position still stands. GTO work was at the point to where it was about 2 years from fruitation when worked stopped last January, and unless someone hit "delete" or shreaded alot of paper, is still frozen in that timeframe till released.

Guess we'll agree to disagree here till some new news breaks out.

 

a lof that is gearing though.. when your car is practically idling while cruising on the highwa, of course you are gonna get good gas mileage...

 

I have to wonder if the EPA tests exactly the same way now as they did then. Haven't they been trying to get a better reflection of real world fuel economy numbers in their tests?

Besides, my fbody is rated for better gas mileage than my Mustang was, but I can tell you from experience that in stop and go driving, the Mustang got better gas mileage, regardless of EPA rating.

 

FS3800, regardless of what advantage the LS1/6/2/7 makes use of to accomplish its fuel economy numbers (copious amounts of torque as it relates to the .5 to 1 sixth gear) The bottom line is that fuel economy can not be used as an excuse for why someone's Solstice I4 is better than a v8. Because its not, even in a much heavier car. In addition, did you not notice that the city numers are only seperated by 1mpg?

RussStang, the EPA #s are the best we have. They're just like dyno #'s in that they are a standardized way to compare cars, whereas our personal drining habits are neither regulated nor standardized (thank goodness). That's one reason why anecdotal evidence holds little value. I personally have gotten 30mpg in my moderately cammed T/A coming back from Vegas and I wasn't driving 55 . But that proves nothing except that the way I drove that night, in that car, at that speed, that's what I got.

Also, going back to this rediculous "Pontiac doesn't need V8's" arguement. Does anyone know which version of the Grand Prix has the most retail sales? Yes, its the 5.3L V8 GXP. The same was true of the Bonneville GXP and the Firebird, ask Guy which ones were the hot sellers.

 

And if you get rid of the skip shift, the mileage would probably drop to 16 in the city. And if the Solstice had different gearing, it would do much better. Clearly, Pontiac went to some trouble to get good EPA numbers on the Firebird, and didn't go to any effort with the Solstice (the same engine in the Cobalt gets much better mileage).

Heck, the Accord Hybrid lost 4mpg for the 2006 model year, because Honda added a sunroof, which put it into the next weight category. Does anyone
really think a sunroof costs 4mpg?

 

If you are making the same amount of power than the same amount of gas is being burned, although I imagine that the turbo should be running slightly richer.

Also don't forget that on the freeway the 4 cylinder has to rotate faster to produce the same amount of power to move the car down the road... and that energy is linear with mass but varies with the square of velocity.

 

A4 LS1 F-bodys still got EPA 18/27 rated gas mileage

 

Actually, my 1998 and 2002 both said 17/25 on the window sticker. I think the 2001 model was 1 higher, though there were no changes between that and the '02. There was never one at 18/27. But so what?
You know, you got one number for the LS1 A4 Camaro, regardless of whether it had a 3.23 or a 2.73 axle. If you ran both through the EPA test, there would have been a difference. So things like a different product mix presumably affected mileage. Look how much the CTS-V dropped when the Corvette stopped using the LS6 V8 in 2005. EPA numbers really need to be taken with several grains of salt!


I looked up mileage in Consumer Reports for 3.5v6 and 5.7v8 Chrysler 300s as well as the 3.9v6 Impala and 5.3v8 MonteSS. CR is good, because they have a test track and they actually run the car they buy. The V6s in both cases were better, though the difference was less on the highway.