Weight has a significant penalty on fuel consumption. Cars will use more fuel because cars today are getting heavier. The gains made in engine/drivetrain efficiency are offset by the vehicle's greater mass. Net result? Zero gains in fuel economy compared to comparable vehicles of only two decades ago.

So are we going to keep adding weight in the interests of passive safety? It's a vicious circle but we seem to be going nowhere fast on the subject of fuel efficiency.

Can we have our cake and eat it? Is there a means to an end?

 

I think Mazda did a better job convincing people that they kept the weight off than they actually did at keeping the weight off. From what I've seen, the Mazda 6 is no lighter than its contemporaries.

The Corvette is the statistical outlier here. Compare just about every vehicle that plays in the same market in 2010 that it played in 1990, and you'll see somewhere around a 20% gain.

Here's the difference. Back in 1990, the Corvette was not an intensively mass-controlled car like it is now. In fact, it weighed about as much as the Camaro, in spite of the fact that it was only a two-seater. If they'd worked as hard on that generation as they did on the current, it likely would have come in under 3000 pounds. The other thing I notice is that the Corvette only added 25% to its torque figure, where the Camaro and Miata added 40%.

I don't like mass any more than Charlie does, but I try to be reasonable about it.

Giving up features that the market wants seems like a loser to me. Giving up features that the government requires definitely is. What's left is more intensive efforts to control weight through careful engineering and lightweight materials. Every manufacturer says they're working on it, and I'm waiting to see the results. Mercedes and BMW made a lot of noise about controlling weight, but their new generation vehicles continue to be heavier than the previous.

When Ford came out with the previous F150 around 2002, it was hundreds of pounds heavier than the previous. They said they'd work on reducing the weight. The new one is just as heavy as ever. Apparently all the work they put into it only managed to hold the line. That seems to be the most common result.

 

I read somewhere that the new Jag XJ has a base curb weight a little under 3900 pounds. If true, that's pretty good considering it's a 385hp luxury car. The new Porsche Panamera is almost as light. The Jag has an aluminum unit body, while the Porsche has lots of aluminum parts in its construction. I'm always suspicious of these numbers, however, as they often seem to go up when production cars are tested. But they're still promising.

Will the market pay for this sort of lightweight construction in mainstream cars? Could Chevy build a 3100 pound Malibu with a 2.4DI I4, maintaining comfort and safety attributes of the current 3600 pound model? I don't see why not. How much would it cost and would people buy it at that cost. I'm sure this is the sort of problem that design teams at every car company are facing.

 

By the way, it's not just passenger vehicles that have gotten heavier.

Back in 1970, the GM 40' bus with a 6V71 and no A/C seated up to 53 passengers and weighed a little under 21000 pounds. With A/C and the 8V71 needed to make the bus go when it was on, weight climbed to around 22500.

By the mid 90s, most transit buses weighed close to 30000 pounds and seated only 43 passengers. But they had more powerful engines, wheelchair lifts, stronger, more crash resistant bodies, a ton of electronics, etc.

These days, they can be a bit lighter, as some mfrs have switched back to aluminum, (the GM bus had a lot of aluminum in the body, but most in the 90s used steel). But those with hybrid or CNG systems can be over 30000 pounds due to the weight of batteries or CNG tanks. Unfortunately, the number of seats on modern low floors is down to around 38.

 

Hence me saying have higher gas taxes if you want lighter cars. I fully understand weight and fuel economy.

 

Yes, as fuel prices go up the weight will go down.

Politically unpopular but this is the only way. I'd have no problem with an extra $1 of gas tax if it went to making improving road and bridge quality and mass transit.

$4-$5 isn't so bad in a world of 3500lbs. 300HP 35mpg Camaros, 32mpg+ SUVs, and 40-50mpg C segment cars.

Just so everyone know, the new Ford Fiesta gets 65mpg (US not imperial) over in England with the 1.6L diesel. Driving that with $6-$7 fuel is like driving an Aveo today (fuel price wise)

 

I still don't see your point as the car makers have to abide by increasingly stricter safety standards which invariably means heavier cars...

If the law makers postponed the introduction of new safety measures, the automakers might actually develop ways to make cars lighter. Higher fuel taxes will not negate weight increases due to increased structural integrity built into future models. Not unless you could explain your point in more detail...

 

I'm reasonable and even thoughtful - I'm just not willing to accept the status quo. Why were we told Camaro needed to be so heavy again? One reason was so it would receive 5 star crash rating all around. Hmmm.

BTW, the 1990 Camaro was available with up to 330 ft/pounds of torque.

 

You seem well versed in bus nomenclature...

 

True. But I dont have a 5th gen Z28 to compare it to yet

I noticed that too. I was going to chime in about Class 5-8 trucks, which have also put on a lot of weight, but I dont think it is entirely relevant. How many class 8 trucks have even *one* airbag?

But everything has certainly gotten heavier. A lot. But when people scream how heavy the Camaro has gotten - everything has - and people just dont realize it. I'd prefer it was lighter (who wouldnt?) but its not like it was poorly designed. The Chassis is heavier than it needs to be, but it isnt out of control... "when a G8 is 4200lb and a M5 is 4100lb and a Charger is 4200lb" sort of thing.

Just as we cannot strip a lot of features away to make a lightweight stripper model. It wouldnt work. Where does the F6 belong? How will alpha stack up? Will a smaller CTS be in our future?

Where's my crystal ball...

 

So when law makers decide to pass the new safety measures, the automakers are just going to add more weight? You are also implying that automakers are already looking at how to keep weight out of cars. Relaxing the safety standards for a few years would just delay the weight because automakers are already looking for way to keep it out.

The point I am making effects the market. When people want more fuel efficient cars, they will buy them. Since weight is a huge factor in that, they will buy lighter cars. If customers still want a big vehicle and better fuel efficiency, someone will make it and it will be a huge success. This will come from weight being cut, more fuel efficient engines, and possibly from less content.

The market today wants lots of content for small prices. They want fuel efficient engines, but they aren't saying then need 30mpg city. Till the market changes and demand changes, weight isn't a problem for 95% of the people out there.

 

Yeah, the point was that everything has gotten heavier for various reasons.

Exactly. In the context of 2010 model 4 seaters with IRS & 426hp/420tq, the Camaro isn't heavy. It's actually on the lighter side.

If there is an F6 with a V8, Charlie will be back to complain about its weight.

 

Oh man, I don't think I could handle another few years of listening to you justify it either.

But if GM screws the pooch that badly on it, I'll probably be too old to care.

 

I.e. brings out a competitive car instead of a fantasy car? I'm hoping for fantasy, but will be satisfied with competitive.

 

You can only mask mass for so long, before even the most uninterested driver begins to notice. There have been afew road tests of the new SRX already.

The common threads are:

1) Top notch interior.

2) Lexus rivaling quiet.

3) At 4500 pounds, the base 3.0L and mileage tune trans combo is painfully slow and unrewarding to drive. In fact the reviews were so bad, that GM had some of the magazines to an emergency re-test with the more powerful 2.8 turbo. The old SRX, BTW, was an absolute joy to drive.

Cadillac has invited me to a test drive later this month, between the SRX, RX350, X5 and GLK. I'll let you guys know how it goes...