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Discussion Starter · #1 ·
This car is kind of overweight and I find it odd that GM didn't go with an aluminum hood. I bet it would save 20 pounds easily. My old F150 cheap base model pickup had an aluminum hood. For a car that's trying to maximize milege GM made some funny choices.
 

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cost vs. weight savings I'm sure. There's only so far you can go before you drive up the cost of manufacture. There's a ton of things (no pun intended) they could do, but certain things must be kept in mind, and I'm sure at the top of the list is cost.
 

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really the bulk of the weight is going to be the options packages, this car comes very well equipped with safety and entertainment packages. Downside to cars with technology, if you don't go crazy with exotic metals (big bucks) it is going to have some heft. My ECO weighs 2900 pounds curb weight, which now adays isn't too bad
 

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Discussion Starter · #4 ·
I understand the cost choices - it's just funny where GM decides to spend money vs save money. Like the very expensive forged wheels on the ECO. You'd think an aluminum hood would save more gas per dollar spent than forged wheels, especially when Ford can put one on every F150. And I totally don't understand the cast iron block. I read somewhere on this forum that the iron block has sleeves. I could understand an iron block because it's cheap and has fewer parts but not if they need to go to the trouble of sleeving it. So Chevy sells an aluminum block in their pickups and a cast iron block in their high mileage car. I'd like to have been a fly on the wall when the engineers were deliberating these decisions.
 

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It has to do with the cost vs savings. The more aluminum they put on the cars for sheet metal or engine parts, the higher the price is going to be. They need to keep the cost down to compete with other cars. Just because you had an F150 that had an aluminum hood doesn't mean anything.

Also, for the repair world(as I am in) with aluminum parts, when it gets damaged or dented we replace it. There are very few body shops that have aluminum repair tools. So that means GM would have to manufacture more AL hoods at a higher price for repair shops. With the steel hoods, they will be able to be repaired almost all the time.
 

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A savings of a few pounds on a hood or the almost 20lbs savings in the rims and the reduction in rolling mass....seems like a no brainer to me!!
Absolutely! A pound off the drivetrain is WAY more efficient than a pound of the entire car. You would be hard pressed to save 7 pounds in an aluminum hood and have structural rigidity.
 

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Discussion Starter · #10 ·
I don't know about that. I had an EVO and an STI and they both had aluminum hoods. There's a huge difference. You're right about rotating mass but the point I was trying to make is hood should be pretty cheap judging by the use by Ford.

When GM was engineering the C5 Corvette they developed a mathematical model that showed the cost/benefit of saving weight. At that time they said it was worth up to $10 in extra production cost to save a pound of weight. Anything they could do for $10/pound was a net plus for the vehicle. They surely must make engineering/cost tradeoffs and analysis because they use aluminum lower control arms on the Cruze but not very much elsewhere. It kind of facinates my why companies make the engineering choices they do and why differenct companies make vastly different choices when facing similar issues.
 

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Taking weight off the wheels is pretty typically around a 7:1 ration... acceleration/city efficiency wise, if they took 20# off the wheels by going forged aluminum, they saved 140# off the weight of the car... They also made less unsprung weight on the suspension, so those parts could be lighter...

If you do a little bit of research on the engine in this vehicle, you'll find out that the block is "hollow cast" or "hollow frame" cast iron... I read somewhere else that in order to make an aluminum block as strong, it would end up weighing as much as this block...

The new Ecotec 1.4L turbo engine is built on a strong, low-mass foundation that supports its high-performance, high-efficiency attributes. Details on key features include:
Cylinder block – It is made of strong gray cast iron, with five reinforced main bearings. The block offers excellent thermal properties that suit the cylinder pressure and loads generated by a turbocharger system. To minimize weight, it features hollow-frame construction, making it about 20 percent lighter than a conventional casting. The block also incorporates a gray cast iron bedplate that helps reduce engine vibration.
More information here: 2011 Chevrolet Cruze – Powertrain and Chassis details [Archive] - CleanMPG Forums
 

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Comparing the Cruze to an EVO, an STI or a Corvette is like comparing a Cessna and an F-16. You are talking $35,000+ performance cars Vs an econobox people hauler. It isn't a fair comparison. I'll take the added weight for the amenities over the atrocity Honda is calling a Civic nowadays. Bottom line you have a very well equipped, reasonably priced car and a **** of a deal for the money. I would be willing to bet that when/if you see a performance Cruze you will see some weight reduction but the vast majority of people buying this car won't give a second thought to if they saved a few pounds with an aluminum hood, they will buy it because it has a good deal of amenities and gets really good gas mileage
 
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