GM's Ongoing Weight Problem

[bigtime]

Another example:

Mazda miata 2445lbs. vs. solstice 2860lbs.
The miata retractable hardtop is only 2575lbs.
That translates to slighty worse MPG. 19/25 for the solstice, 22/27 for the miata.

[big swede]

Originally Posted by Buick61

The Vue and CTS are some of the more egregious examples of fat-messness.

The G6 was also super fat even before the 3.6 and 6 speed. It used to make me crazy hearing people complain about OHC being too heavy and then the G6 with the OHV V6 come in even heavier. If your going to use OHV make sure you use an aluminum block, otherwise your giving away one of the biggest advantages.

I agree with the others. It's not like other manufacturers have less content or less rigid chassis so that's no excuse. GM needs to get serious about weight loss. The most recent cars coming from GM and getting great reviews, so can you imagine how much better they would be if they both dropped 300lbs.

Originally Posted by burningsquirrel

i will cry if the camaro is over 3600 lbs again.

You better start now because there isn't a chance in hell that it will come in under 3600lbs. The G6 with a FWD V6 smaller brakes, wheels, suspension, etc... weighs more than that.

[86fleet]

Originally Posted by skepticman

They will not gain a few miles per gallon by shaving 100 pounds. The EPA says you will save 1-2% per 100 pounds:

http://www.fueleconomy.gov/feg/driveHabits.shtml

Weight is only one factor among many, including aerodynamics, rolling resistance, engine design, driving habits, and so on.

I agree, but don't forget that more weight means more power to achieve a similar level of performance. A couple hundred pounds can definatly mean the difference between being satisfied with the 4/6cyl version of a car, or having to move up the the V6/8 to get the performance you desire.
Even though the extra weight alone only decreases fuel economy by a very small amount, the extra weight plus the "need" for a
bigger engine has a far more significant effect.

On an unrealated note, it takes me forever to type...

[bigtime]

Interestingly, when you compare the tahoe vs. the sequoia its advantage tahoe. Over 400 lbs. lighter and better mpg. Seems GM is spending a little extra time on making their trucks more efficient.

[I-Love-Pontiac]

Bob lutz addressed this in an interview. He mentioned that GM has just recently made weight a priority. He also made it sounds like any platforms that have already been engineered are not going to get any lighter.

http://www.theautochannel.com/news/2...26/071845.html

He talks about weight later in the video

[AdmiralViscen]

Originally Posted by DuSpinnst

The Malibu uses a chassis designed in 2003. The hardpoints can't be moved until the EPII chassis.

The only program that shouldn't be fat but is, is Theta II.

How about Lambda?

[rlhmarine]

I wonder if GM's desire to provide a value price point leader in the car segment is culprit and/or the focus for safety designed in their car's with the use of off shelf parts being shared by most or all their platforms in money losing North American market. With the car divisions of GM being the money hemorrhaging side for so long, it's tough to think they would add more fuel to the fire by developing these higher cost weight saving pieces for alot of these platforms in the past years.

[MelvinJ]

Originally Posted by BigAls87Z28

GM's Ongoing Weight Problem
By BigAls87z28
GMInsidenews.com


I did not think it could get worse. Usually when someone says that in their writing, it does. And, boy does it get worse. I kept going up the ladder, and took a look at the Cobalt against the Mazda 3, Honda Civic, and outgoing champ Toyota Corolla. Unlike the Aveo, where it was not the heaviest in its class, the Cobalt takes that title by over 400lbs to its nearest competitor, the Mazda 3. I decided to see if I can find something heavier to at least make the Cobalt look somewhat slim. I pulled up the heaviest car that could possibly take the title away. I grabbed a 2007 VW Rabbit four-door hatchback five-cylinder auto. I plugged in the car, and to my absolute astonishment....IT WAS STILL LIGHTER THEN COBALT! No way. No way did the German tank come in under the Cobalt. Had it beat by 80 pounds or so. The Cobalt's dimensions are no different than of the others. It’s simple strut front end and solid twist beam axle in the back is old compared to the multi-link rears from its competition. The only car I could find in GM stable that was lighter than its competition was the Corvette. From base C6 to ZR1, its hundreds of pounds behind its competition excluding Porsche.

Al, where are you getting the weights for these cars?? I knew the Cobalt wasn't as bad as you made it out to be, so I did my own checking.

All 4-doors, manual trans, from the manufacturers' websites:

Cobalt - 2747
Civic - 2628 (A/C not included in this weight)
Corolla - 2530
Sentra - 2885
Mazda3 - 2780 (A/C not included in this weight)
Rabbit - 3072
Lancer - 2922 (A/C not included in this weight)
Elantra - 2723 (A/C not included in this weight)

Average: 2785

The Cobalt is right in the middle of it's class, especially considering half the cars' weights above don't include A/C that the Cobalt has in it's standard spec weight.

I didn't check the other cars you mentioned, but if your numbers came from the same source, they should be checked against other sources.

I also checked just a few mid-sizers too. Chevrolet doesn't have the Malibu's weight posted, but I checked the G6:

All automatic/4-cylinders:

G6 - 3305
Camry - 3307
Accord - 3289
Altima - 3189

At the basic 4-cylinder level, the G6 isn't too bad, but I know the loaded Malibu/Aura test weights I've seen in magazines have been 100-150 lbs higher than comparable models, so perhaps the optional powertrains or equipment are more responsible. The short wheelbase 2004-2007 Malibu came in well under 3300 lbs.

[jasaero]

Originally Posted by BigAls87Z28

Accord is BIGGER in every dimension, yet is a few hundred pounds lighter....

This guy made a valid point. The malibu DOES have a 2 inch longer wheelbase. The structure required for that extra wheelbase will add up faster than overall dimensional structure.

A few hundred pounds is a stretch between these two cars also. Even the most decked out V6 versions only differ in weight by 50 pounds per MSN.autos.com.

http://autos.msn.com/research/compar...6247&v=t106150

I will agree with your write up in general though that GM needs to work on weight.

[tkrelston]

Originally Posted by Buick61

The Vue and CTS are some of the more egregious examples of fat-messness.

And look how they have been called the new benchmark in interior quality. The weight creep is a problem, but there are far more important problems than just the weight. Cars that weigh more have the feeling of quality. Look at the luxury cars from Germany; they are all 4000 lbs, often more. If you want a good comparison look at the GTO compared to a 6-Series. The GTO is bigger in all but two dimensions and ends up lighter weight. Cost aside, they are very similar vehicles.
The types of plastics used in a car have very profound effects on the quality feel of a vehicle as well as the weight of the vehicle. Remember also that most plastics are still made from petroleum, so reduction of weight thru plastics is ultimately using more oil than those made of heavier materials.
The only seriously overweight vehicle would be the new Vue. Unless you all wall 1980s quality again, I suggest you give GM a break, then again, with GM hell bent on making sure Cadillac remains a 200,000+ a year division, I figure, every other division will have to make sacrifices for CAFÉ.

[delmarjohn]

You know unless you drive 60,000 miles a year ,and you no longer want content and safety ,please be my guest and shave that 100 pounds ,it means nothing to me ,I drive what I like and I don't go in asking what the car weighs ,sure down the road cars will be lighter as new materials come on board ,electric cars will weigh less just for the simple reason of simplified transmision functions ....but extra air bags weigh more and hard drives have weight ,bluetooth ...what we pack into cars today with regard to features,and mandated requirements ...oh but that 100 pounds ...not important to me

[rlhmarine]

While I was stationed overseas in Japan, I noticed early on that Japan's strong point is making small cars very well. America's strong point was fullsize cars and trucks. They have some cars as small as ATV's with bodies. So they have a slight advantage in knowing how to hold the line on weight since they are taxed on the weight and size of their cars and trucks.

[camaro_freak]

Originally Posted by I-Love-Pontiac

Bob lutz addressed this in an interview. He mentioned that GM has just recently made weight a priority. He also made it sounds like any platforms that have already been engineered are not going to get any lighter.

http://www.theautochannel.com/news/2...26/071845.html

He talks about weight later in the video

so recently they've made a priority to be a serious auto maker

exterior design, interior design, fuel economy and weight savings all have become a "priority" over the last few years...

wtf GM...

[ogg vorbis]

Originally Posted by bigtime

Another example:

Mazda miata 2445lbs. vs. solstice 2860lbs.
The miata retractable hardtop is only 2575lbs.
That translates to slighty worse MPG. 19/25 for the solstice, 22/27 for the miata.

how about comparing same engines/drivetrain??

you should be asking whether a miata chassis can take an LS7's power and torque. the miata has 140 lb-ft...

still, while resonant frequencies may be similar, torsional strength is another matter. resonance plays into road irregularities being amplified by the body. torsional strength is stiffness.

the accord uses much more ultrahigh and high tensile strength steel. stronger steel means LESS weight - the article seems to suggest the opposite.

crashworthiness is not just a 5 star rating. a solstice will crush a miata, although they're both 5 star. nhtsa states that ratings are only good between cars +-250 lb.

[CobaltSScrazy]

I agree with your theory, though your numbers may be flawed AL. I believe MOST GM cars are a few inches longer/bigger than MOST of their competitiors...of course there are exceptions though.

CobaltSScrazy