Gearhead Jim

Our current car is a 2009 Coupe, A6, Z51, 3LT interior. Each of those options added some weight.
The window sticker does not list an empty weight, nor do the door stickers. And different people have different definitions of "empty".

If we buy a C7, it will have the same options.

I'm trying to figure out what the weight difference would be from the C6 to the comparable C7, and not having much luck. I'm thinking the C7 Z51 would be about 150 lbs heavier, but that's just a guess.

Does anyone have good Z51 numbers for both cars?

Thanks.

Snorman

GM has never released curb weights for the Z51, only the non-Z51 cars (3298#)
While the magazines have printed "curb weights" for Z51 cars, it's not an apples-to-apples comparison. I think 150# is generous.
One of the rags commented that the Z51 was 69# heavier than the last GS they tested (a few mags listed the Z51 at 3444#). But true weight of the Z51 seems to be thus far somewhat elusive.
S.

JoesC5

On the C6's drivers door is the gross weight. On the driver's door jam in the maximum cargo(includes passengers), which is 423 pounds. Subtract the 423 pounds from the gross weight and you have your car's weight.

It would be interesting if the new owners of C7's would post their gross weight along with the maximum cargo weight along with the model(Z51 or non-Z51) along with it's options, etc. Then we can compare that weight against the GM published curb weight of 3298 pounds for the non-Z51 and 3444 for the Z51.

Snorman

When did GM publish 3444# for the Z51?
S.

Gearhead Jim

The door sticker on our car shows GVW as 3,782. Minus the 423 payload, that gives an empty weight of 3359; that's only 85 lbs less than your number for the Z51 C7. I suspect that the GM numbers are with the (lighter) manual tranny, lower weight interior, etc. But that's just a guess...

Snorman

To be clear...GM has not listed the weight of the Z51, much less at 3444#.
Joe is comparing GM listed weight for non-Z51 cars to magazine published weights for Z51 cars. Apples to oranges.
S.

MeanDean43

Im tired about all of this BS about the Z51 being overweight. It suffers from the same problem that I do, (it's UNDERTALL.)

JoesC5

You are correct as I was quoting Z51 weight from the auto rags. Since most of them get their "facts" from GM, I am assuming they are close to being correct. The C7 Z51 has a heavier engine dry sump system, a heavier rear sway bar(the non Z51 doesn't have a rear sway bar), a heavier differential as the eLSD has a separate hydraulic power system etc., additional heavier radiators, ducting and fans, and the Z51 has heavier brake rotors up front and I suspect slightly heavier wheels/tires. Wouldn't surprise me if all those additional weights add up to 146 pounds. 3298 + 146 = 3444 pounds.

All one has to do is ask a new Z51 owner with zero options that add weight, to give us the gross weight of his car and the max cargo weight(in case it is different from the C6).

MY 2009 Z06 has a curb weight(from GM) of 3175 lbs, but it is not a base car with zero options. It is a 2LZ with NAV and chrome spiders that do add additional weight. My car weighs 53 pounds more than a base 2009 Z06 with no options.

Jim's 2009 has curb weight of 3217 pounds for a base no optioned coupe. Add in his auto, Z51, 3LT trim and his actual weight is 3359 or 142 pounds heavier than the base no optioned car at 3217. I read that the 6L80 is around 122-125 pounds heavier than the 6M manual transmission. The C7's 7m transmission is heavier than the C6's 6M. I read somewhere what the additional weight of the 7M is, but don't recall it at this time.

ChucksZ06

All that and you still have to put them on scales to see what they really weigh.

Snorman

Really? Is this why GM listed the weight of the Grand Sport at 3311# and the most recent MT test (comparo against a 991 911) listed the GS at 3375#?
We can go all sorts of ways using that logic.
S.

JoesC5

Did MT actually weigh the GS you are referring to? How else did they know it weighed 3375 pounds? maybe they didn't weigh the GS, but instead looked at the GS's gross weight(posted on the car) and subtracted the cargo weight(also posted on the car) and came up with the 3375 pound figure.

GM says my Z06 has a curb weight of 3175 pounds, but if you were to actually weigh it, it would be closer to 3228 pounds because the curb weight GM shows is for a base model with zero options and my Z06 is a 2LZ(heavier), has NAV(heavier) and has chrome spiders(heavier). Thus it weighs 53 pounds more than GM's posted curb weight of 3175 pounds. Yet GM's posted curb weigh of 3175 pounds is still correct. I know what my Z06 weighs(3228 pounds) yet I've never weighed the car, and I fully understand why that weight is 53 pounds heavier than the 3175 pounds that GM said is the curb weight of my car.

Most likely the GS that MT weighed(how else would they know its actual weight since they didn't quote GM's curb weight of 3311 for a base model with zero options) had a higher trim level and other options that caused that particular GS to be 64 pounds heavier than a base GS with zero options.

It's not rocket science to understand why a car that is weighed, weighs different from a manufacturer' stated curb weight. It does not mean that the manufacturer is a liar, or the magazine, with their stated weights.

Gearhead Jim

If Joe's/GM's numbers are correct, then a Z51 C7 would weigh about 227 lbs more than our Z51 C6, with similar options in each car.

That's a lot, enough that the two cars could end up equal in a drag race. Of course, the C7 would be quicker around a road course. Since I don't race in either venue, that's of only minor interest to me. But those who love or hate the C7 will find lots to jaw about.

EDIT:
I do recall one of the car mags explaining how they come up with all their numbers several years ago, both GM and the magazines have to decide what fluids to include, how much gas, driver (?), etc. So two sets of numbers for the same actual car, might be different but both honest.

AORoads

So, joe and jim, let me ask a question that seems to have been answered: the gross vehicle weight on the door IS for whatever is the weight of the base model, PLUS all the car's listed, from-the-factory options? such as 2LZ, nav, etc.?

Which then means, any "stripped" car w/o options will have a gross weight on the sticker at the least high number when you subtract max cargo.

Am I correct in what I've just written?

JoesC5

You lost me with the second paragraph.

The Gross weight on the door is what that particular car weighs including the maximum cargo weight. each car's gross weight is different unless you are comparing two identical equipped cars.

I checked with another forum member several years back that had a 2009 Z06 with 2LZ and NAV and chromes. Their car's gross weight was one(1) pound different then my gross weight. I don't know why there was a one pound difference between out two seemingly identical cars, but there was, and GM knew it.

It's not practical for GM to list the exact curb weight of every individual car they build on their website. They can't post on their web site that Joe's Z06 has a curb weight o 3228 pounds but Mary's Z06 has a curb weight of 3227 pounds.

But they can post it on the sticker(that is required by federal law) on the driver's door.

JoesC5

by definition, a vehicle's curb weight includes all fluids, including a full tank of fuel, but does not include people, dogs, coins in the glove box or a GPS stuck on the windshield.

I don't understand why any magazine has to try and figure out what "curb weight" means, as it is clearly defined. If a car specifies 12 quarts of coolant, then the curb weight includes 12 quarts of coolant, not 10 quarts or 14 quarts. Same goes with transmission fluid, engine oil, differential gear oil, windshield washer fluid and fuel.

I grabbed this off the net....






A Weighty Issue: Shipping Weight and Curb Weight
Written by Aaron Severson
Monday, 14 December 2009 15:14

A car's weight has a dramatic effect on its performance, ride, handling, and fuel economy. Figuring out how much a car weighs should be simple, but the weights listed in brochures, road tests, and other sources can be contradictory and confusing. A vehicle's specifications may list shipping weight, manufacturer's curb weight, and gross vehicle weight ratings, all of which are quite different.

To sort out this confusion, let's look at what each of these terms means.



Dry Weight

Dry weight is a vehicle's unladen weight with a completely empty fuel tank and no engine oil, coolant, or other fluids. As you can probably guess, dry weight is consequently much less than the car's actual, on-the-road weight. A gallon of water weighs about 8.4 lb (3.8 kg), a gallon of gasoline about 6.3 lb (2.9 kg), so just adding fluids and filling the gas tank can add 150 lb (68 kg) or more to a car's dry weight.

Since passenger cars are generally (though not always) shipped with oil, coolant, and other vital fluids, dry weight is not often quoted for complete automobiles, although the term is sometimes used, albeit not always correctly, as a synonym for shipping weight. However, the quoted weights of automotive engines are almost always dry weights (and may or may not include accessories or the weight of the flywheel or flex plate).

Shipping Weight

Unless you pick up your new car directly from the factory, the manufacturer has to ship it to dealers by sea, rail, or truck. Because freight charges are usually based on weight, automakers frequently publish a standardized shipping weight for each model they sell. If a model is available with a choice of "standard" engines -- e.g., a mid-1960s Chevrolet with either a six or a V8 -- the manufacturer will sometimes list separate figures for each engine or quote the additional weight added by the larger engine and its associated equipment.

Shipping weight usually reflects a "stripped" model with a standard engine and no optional equipment. It typically includes engine and transmission oil, engine coolant (if the engine is water-cooled), and at least a modicum of fuel, enough to start the engine and drive the car off the truck or transport pallet. In some eras, however, filling the radiator and fuel tank were left to the dealer. As a result, it's not easy to be sure whether quoted shipping weight included those fluids without detailed knowledge of a particular automaker's standard procedures in that period.

Like dry weight, shipping weight is usually substantially less than the car's actual, ready-to-drive weight. Aside from the weight of fuel, optional equipment or engines can add a great deal to the car's total mass. For example, a 1965 Ford Mustang with the optional 289 cu. in. (4,728 cc) V8, automatic transmission, power steering, radio, and power brakes weighed at least 400 lb (181 kg) more than a stripped six-cylinder model. Adding to the disparity, a lot of equipment we now take for granted, such as heaters, turn signals, and even spare tires, were at least nominally optional in earlier eras. It's unlikely that many cars were built without those features except perhaps by special order for fleet buyers, but since those options were not technically standard equipment, their weight was not reflected in the published shipping weights.

Shipping weight is best understood as a particular model's practical minimum weight in stock form. For that reason, some racing organizations have used factory shipping weights to determine eligibility for different racing classes. (Depending on the rules of the specific class, a minimum weight figure may also be imposed to limit competitors' ability to further lighten the car by removing trim and standard equipment or substituting lightweight components.)

Curb Weight

A vehicle's curb weight (or kerb weight, for our British readers) is its weight in ready-to-drive condition, with fuel in the tank and all necessary fluids, but without a driver, passengers, or cargo. In the United States, curb weight is usually measured with a full tank of fuel. For cars sold in Europe, automakers today frequently specify DIN curb weight, which is with the fuel tank 90% full.

European Union type approval rules also require manufacturers to specify a vehicle's weight with the fuel tank (or tanks) 90% full plus an additional 165.3 lb (75 kg) to account for the weight of the driver and a small amount of cargo. The total is often called E.U. curb weight or licensing mass.

The manufacturer's curb weight is the curb weight listed in the automaker's official specifications. Depending on the market and the manufacturer, this may be the E.U. licensing mass or the car's weight with either a partial or full tank of fuel; there's often no way to be sure just by looking at the spec sheet. As with shipping weights, these figures generally do not include optional engines or equipment. Some manufacturers specify an average figure or list separate curb weights for each model and powertrain combination. (The E.U. requires automakers to calculate the mass of optional equipment to ensure that the options don't push the vehicle over its maximum safe load limit, but the mass of that equipment isn't necessarily published.) Most automakers simply list the weight of a stripped model, although automakers occasionally publish lists specifying the additional weight of major options, such as automatic transmission or air conditioning.

Some independent auto testers actually weigh each of the vehicles they test and list the vehicle's actual curb weight in the test results. These figures are typically higher than the manufacturer's figures because they reflect the optional equipment the car actually possesses, rather than the standardized figure.

Some magazines and testers also list the actual test weight of their subjects, which is the curb weight plus the weight of the driver and any test equipment. In the 1950s and 1960s, in particular, test weights were often substantially higher than curb weights, reflecting the bulk of period test equipment and, in some cases, the necessity of carrying a passenger to operate it.

Gross Weight and Gross Vehicle Weight Rating (GVWR)

A car's gross weight is its curb weight plus the weight of its driver, passengers, and cargo. A car's gross vehicle weight rating (abbreviated GVWR, but often confusingly listed as just gross weight) is the manufacturer's recommended maximum loaded weight. The vehicle's maximum load is the GVWR minus the curb weight. For example, a Honda Odyssey EX minivan has a manufacturer curb weight of 4,475 lb (2,030 kg) and a gross vehicle weight rating of 5,952 lb (2,700 kg); its maximum load is 1,477 lb (670 kg). Naturally, a vehicle's actual gross weight changes depending on how many passengers and how much cargo it's carrying, but its gross weight rating does not.

Gross weight ratings usually assume the standard suspension and standard tires inflated to the recommended pressure. Manufacturers occasionally specify different gross weight ratings for different combinations of suspension and tires, although that is more common for trucks than for passenger cars.

In many nations, including the U.S., gross weight rating determines what roads a vehicle is permitted to use, what type of driver's license and insurance are necessary to operate it, and the emissions and fuel economy standards it must meet.

APPLES TO ORANGES

At Ate Up With Motor, one of our goals is to put each of the cars we discuss in context, both with other cars of its time and with modern vehicles. Unless otherwise noted, when we refer to a car's weight, we mean its actual curb weight with a full tank of fuel, not its shipping weight or gross weight rating.

As you can see from everything above, calculating the actual weight of a vehicle with options and a full tank of fuel can be tricky. A lot of sources simply quote the manufacturer's or other published figures without specifying (or perhaps even considering) whether those figures are curb weights or shipping weights, whether they reflect the weight of optional equipment and a full tank of fuel, etc. And don't get us started on the quaint habit of older British publications of rounding all masses to fractions of a hundredweight. (For those not familiar with pre-metric Imperial measurements, a British hundredweight, abbreviated cwt, was equal to 8 stones or 112 lb, which happened to be roughly equivalent to 50 kg or 1/20th of a metric ton.)

As a result, the weights we cite are usually approximate. We would much rather tell you, for instance, that a car weighed "about 2,400 lb" than claim it weighed exactly 2,408 lb at the curb; the latter figure might be true for one specific car with one specific combination of equipment and amount of fuel, but won't necessarily be accurate for a different example equipped slightly differently. If you compare our estimates with the specifications of other cars (or figures listed in different sources), be sure to note whether the numbers to which you're comparing them are referring to curb weight or shipping weight -- as you can see, it can make an enormous difference!

Hot Rod Todd

So the OP admits they don't ever drag race or road race (AKA Poser). What's the point of this post? The C7 is far superior to your 2009 C6, no matter what the weight. It sounds like another attempt to justify why you should keep your C6.

Even racers who spend a lot of time on the track are not as obsessed by weight as a bunch of individuals on this site. I'm almost ashamed that I contributed anything to another worthless post about weight.

sprtplt

Another apologist. If the total C7 weight had gone down, you would be crowing about it.

sam90lx

Give it time...the mags will weigh it. I think it will be close to 3400 lbs. (loaded Z51)

sam90lx

Gearhead Jim

Just to clarify my post #12:
Our current C6 is our fourth Corvette.
All of the others have been drag raced, autocrossed, and used for multiple HPDE events. Only at Spring Mountain (Bragg-Smith), for convenience I used their car instead of my own.
All of the others were also used as year-round daily drivers in the Chicago area.
Our current C6 has accumulated 62,000 miles in the four years since purchase.

I've been babying this one because I haven't yet decided whether to keep it long term, or trade for a C7. Both cars have their advantages, and it's hard to make a decision when I can't yet test drive a C7.

If that makes me a Poser, then I'm in good company.