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Sedans Chevrolet Cobalt Chevrolet Cobalt Real World MPG
295 messages, Last post on Nov 23, 2009 at 4:23 PM
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Replying to: jameer (Dec 23, 2008 8:22 am) 1. If these tweaks to tires, gear ratios, etc were so minor (ie: it wasn't accomplished with a radical new engine design) then why did it take Chevy so long to produce it? 2. If Chevy was capable of accomplishing this, why are they, along with GM, Chrysler and Ford, bitching and moaning about trouble meeting higher EPA standards?? 3. If Chevy can accomplish this then why on earth can't Toyota and Honda et al?? Has the world turned upside down? Needless to say, I'm utterly befuddled by this information. |
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Replying to: gr00v3 (Dec 23, 2008 9:02 am) Now which engine is pumping more air at 60 mph on the freeway? A 1.5 liter engine turning over at 3500 rpm? Or a 3.0 liter engine turning over at 1750 rpm? Trick question - they are both pumping the same amount of air. The smaller engine is running twice as fast to do its job as the 3.0 liter engine. While the example is hypothetical, this is one of the main reasons that larger engines often have the same gas mileage as smaller engines - because the larger engine is turning over at lower rpm. I had a Yaris '07 with stick and a Cobalt '06 with stick (before the XFE tweaks). I got 37 mpg with the Yaris and 33 mpg with the Cobalt, over essentially the same route to work and with similar recreational driving habits. On long trips, the Yaris dropped to 35 mpg and the Cobalt came up to 35 mpg. Probably because the Yaris was running at relatively higher rpm than the Cobalt and there was more of a penalty at constant high speeds on the Yaris. Also some larger cars run "extra lean" and have better fuel injector design, which allows pretty good efficiency. In my experience, owning about 15 small cars over the past 8 years, the weight of the car and type of transmission are the biggest factors in determining fuel economy. Almost all makers design their vehicles for fuel economy. Compare modern cars with my 1967 VW Beetle with 40 horsepower engine which got between 25 and 28 mpg on my commute from the Valley to USC - modern cars are much better. Or to my '56 Chevy with 6 cylinder and 3 speed manual transmission - that got 18-20 mpg. We've come a long way. So why does the Yaris come with a 105 horsepower, 1.5 engine? Because it is a "Euro/Asia"-centric vehicle which MUST be small to fit on smaller, more congested roads, MUST be small to deal with parking, and MUST have a smaller engine since cars are subject to stiff taxes for having larger displacement - which is why the home model cars are often 1.2 or 1.4, and why the performance models often turn to turbo-charging instead of larger displacement. Once the car is designed for a smaller engine, it is often hard to shoehorn a larger displacement engine into the smaller compartment. BTW, Honda and Toyota upgraded the 2.0 engines in their CamCords to the current 2.4 liters and lowered the RPM, and mileage is better, IIRC. So it isn't only the American manufacturers that "break the laws of physics." 2nd BTW - the current Cobalts downshift a little reluctantly at times with the automatic transmission. This is intentional to maximize the efficiently of keeping the engine at lower rpm. It negatively impacts the driving experience for SOME drivers who expect an instant downshift (I just push the pedal harder if I need it). That's why mileage wasn't higher before - because drivers wanted a certain experience more than mpg. Ditto on the stickshifts on both Cobalts (which I don't own in stickshift version) and new Focuse (which I do own). The gearing is quite different so the engine is running slower - but that means when I need more acceleration on the hill approaching the Highway 24 tunnel, I have to downshift to 4th - easy to do, but negatively impacts the driving experience for some drivers who got spoiled by high engine rpm in 5th gear which meant you virtually never had to downshift before.... So yeah, tweaks here and there in the cars can improve mileage. Could Toyota drop the top gear ratio in their Yaris and improve the mileage? Put better fuel injectors in there to improve the mileage? Remap the ECM (engine control module computer)? Yeah, I bet they can, but when they designed the Yaris, they were aiming at low cost of entry for new car buyers, not ultra high mileage, and wanted the driving experience to be as perky as possible for those drivers. If they "tweak" the car the way the Cobalt is tweaked, they might lose sales when people complain it doesn't pick up as well (of course it will, if you downshift dummy!). So in a nutshell there is a "people" or "sociological" side to car design, it's not purely about mpg, and different manufacturers emphasize economy or driveability at different times. At the end of the day, though, its YOUR right foot that really determines gas mileage - do you gauge the flow of traffic and anticipate slowdowns? Do you gradually speed up when traffic flow starts moving faster, or Gran Prix it then brake hard when you speed up too much? I think Americans have forgotten all the neat fuel economy driving strategies that used to be common in Popular Mechanics and Popular Science in the 60's. It's a "go" world nowadays. Heck, even the "Fit IS go!" (as their ad states).
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Replying to: micweb (Dec 23, 2008 11:27 am) But spend 350 miles just cruising at highway speed, and the weight penalty is less important than other factors, and the cars got equal mpg. Even though the Yaris liftback has a good coefficient or aerodynamic resistance.... |
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Replying to: gr00v3 (Dec 23, 2008 9:02 am) 1. If these tweaks to tires, gear ratios, etc were so minor (ie: it wasn't accomplished with a radical new engine design) then why did it take Chevy so long to produce it? The actually accomplished tweaks to the tires, air dam, and transmission very quickly when the marketplace was beginning to respond to rising gas prices. And to be fair the 2009 XFE does have a new engine as well. It is the same displacement but now features VVT on intake and exhaust valves. 2. If Chevy was capable of accomplishing this, why are they, along with GM, Chrysler and Ford, bitching and moaning about trouble meeting higher EPA standards?? All automakers were oppposed a rise in cafe standards, some (including Toyota) were just more vocal about it. The reason is that sinking billions of dollars into fleet development to meet an arbitrary federal standard doesn't lead to an increase in sales, its just expensive. Companies want to invest in response to the market, not in response to regulations. We should thank those that spoke out against CAFE for their efforts to preserve personal liberty and personal choice. American consumers sharply changed their purchasing decisions and driving behavior when gasoline went above $3.50, not in reponse to CAFE or anything else. Its all about the $$$. No political leader in this country has the will to promote a flat and substantial federal gas tax, which would similarly cut consumption for most while protecting the rights of those who are willing to pay for more fuel. Politicians took the path of least resistance (and self preservation) with CAFE. Shame on them. 3. If Chevy can accomplish this then why on earth can't Toyota and Honda et al?? Has the world turned upside down?  They certainly can accomplish this. There is no secret to designing and engineering cars. And their is no magic elf that works in asian-brand factories that makes their cars superior. The Asian brands thumped the big three in cars forced them to improve their entire lines. The lessons were learned and the improvements were made. Its up to us as auto consumers and to give domestics the same open-minded consideration we gave the Asian brands 10 years ago. So enjoy all the great choices that we have now...and no doubt the other brands will make XFE-type tweaks if they haven't already.  I hope my marketing point of view wasn't too much. Lots of great discussion today! Thanks and good job
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Replying to: jameer (Dec 23, 2008 1:23 pm) The ride was reasonably comfortable and the engine had plenty of pep. Cruise would have been nice but I got a weekend rental deal on this Cobalt for around $35. I figured I could rent a car and save gas money and wear/tear vs driving my 19 mpg F150 all weeekend. It worked darn well and I got in a great round of golf at Bully Pulpit in the badlands. http://www.medora.com/attractions/golf/index.html Amazing place if you like a good road trip! |
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Replying to: jameer (Dec 23, 2008 1:23 pm) "The actually accomplished tweaks to the tires, air dam, and transmission very quickly when the marketplace was beginning to respond to rising gas prices" That's the problem with American auto manufacturers (up until now, at least): They are reactive, not proactive. While CAFE standards may indeed have impacted all the auto manufacturers (and yes, Toyota fought them too), it was Honda, Toyota, and VW, among others, who saw the writing on the wall and got to work producing technologies that would address the foreseeable changes in the market. (And it's interesting to note that those are three of the highest quality and most reliable brands in the industry. Surely not a coincidence.) Any nut job with a trailer and a six-pack could have told GM et al TEN YEARS ago that their insistence on continuing to produce big trucks and SUVs would prove to be counter-productive and, ultimately, self-defeating. (One has to ask one's self who was at the helm.) "American consumers sharply changed their purchasing decisions and driving behavior when gasoline went above $3.50, not in reponse to CAFE or anything else. Its all about the $$$." Unfortunately, our history is replete with examples of consumerism driving bad market decisions, instead of common sense and necessity. GM et al insist that they were reacting to what the market wanted, yet the market was bound to shift; all evidence pointed to this. But, once again, Detroit was slow on the uptake; unwilling to change even basic offerings and adjust to changing conditions that even the uninitiated could have identified. Yes, while purchasing decisions are usually decided by cost, we also have a responsibility to act on behalf of the environment--something that few would do voluntarily if not encouraged to do so with appropriate incentives. I know, I know; you can't regulate morality. But you CAN regulate the cost of things, so offering LEV and Hybrid discounts and tax deductions, and special HOV-lane privileges is one way to mitigate those for consumers who care as much about their environment as they care about their pocket books. We've become apathetic, and it shows in our buying as well as our manufacturing habits. "And their is no magic elf that works in asian-brand factories that makes their cars superior." Having abhorred for too long the quality and air of American automotive products, one actually begins to think that there IS a magic elf at work in those Asian factories. Lastly, I find it telling that American car companies begin to fall back on old favorites and old habits when the going gets tough--or perhaps when they simply run out of ideas (Ford even nixing their new "500" label in favor of the old "Taurus" one, for Pete's sake!). Their show rooms are now replete with the big V6 and V8 Mustangs, Challengers and Magnums of their golden years (sure, VW and others have done this, more modestly, but always with an eye toward improving their engineering proficiency, not simply for pomp, bluster, and The American Way). Unwilling to reinvent themselves, or just unable? Anyway, so yeah: I buy Asian. For now.
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Replying to: cbmtrx (Dec 20, 2008 12:23 pm) Do you know how that car was upgraded to get the extra couple mpg? You may want to read up on that instead of complaining about an American car that out does your beloved foreign Japanese car. |
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In early June 2008, when I bought my stripped down 2008 Cobalt LS with auto tranny and spoiler as the only options (no power locks, no cruise), the low sticker price, combined with the generous $2000 GM rebate, and the EPA fuel economy rating were the primary factors in my decison. This purchase was based stictly on practical considerations, and there was less "thrill" involved in buying this car than had been the case for any of my preivous new cars. (Lord knows, there had been way too many of them.) The great thing about this little car is that it has turned out to be so much fun to drive, and the good gas mileage is just icing on the cake. I am no longer concerned with squeezing every single MPG out of it, and I drive it now more like I have always driven, not crazy fast or anything, but not super conservatively either. That little car will get me a minimum of 27 MPG for my daily commute, including my in town trip to eat lunch each day. Sure, I could go back to driving no more than 55 MPH out of the highway and accelerating a little less aggressively in town, and that would bring the MPG up to 28.5 to 29.0. I got tired of driving that way, though, and the excitement over MPG waned. I guess the way gas prices have dropped has been a factor, too. Now, don't get me wrong, I am NOT one of those people who is constantly going back and forth between the brake pedal and the gas pedal and wasting all kinds of gas. I'm just no longer going to the other extreme to maximize gas mileage. I am totally satisfied with that little Cobalt. Well, I DO wish that it had cruise control. I didn't realize how bad I would miss that feature. Tom
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Replying to: tsjay (Dec 27, 2008 6:03 am) 
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2009 Sedan 1LT. Mylink Package, Auto Tranny, 16" Aluminum wheels/tires, cruise control. First highway mileage drive. 166 miles, half on Interstate  65 mph using cruise control, rest on secondary highways through small towns 50-60 mph average. Easy foot, slow acceleration. Moderate hills, some headwind on the Interstate. 30 MPG. Driver's info shows a 25.5 mpg average. 630 miles on the car at this point. A little dissapointed in this mileage, as was hoping for 33-34. 
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