znod

I'd believe it's the car without gasoline (and maybe even without other fluids such as coolant and engine oil! ). But what does "as shipped" mean? What about with vs without sport package? With vs without runflats? With vs without spacesaver spare? With vs without LOGIC7 (probably minimal, but you get the point)? I'd maintain that it's probably the vehicle in its lightest shipping configuration, which may be heavier depending on configuration and options selected.

That's a good question. I have seen different curb weights for similar cars in auto tests--so I have always thought that curb weight was for the car actually being tested--as equipped. Otherwise, the info provided by "curb weight" would be of very limited interest unless the car being tested was the lightest shipping-weight model. If it is the weight of the lightest model, then the phrase, curb weight, is something of a misnomer--even if widely understood to be be weight of this model.

If my interpretation is correct, and actually I am doubting that it is, then hopefully test weight would be curb weight plus the fluids added. These interpretations are pretty much consistent with the difference noted by the poster 3,660 lbs. - 3,494 lbs. = 166 lbs--since this difference might equal the weight of the fluids added. On the other hand, both curb and test weight might be sans fluids, and this difference could be the incremental weight of the options on the car being tested. But, this incremental weight plus the weight of the fluids probably would be more than 166 lbs.

My bottom line is that I don't know what the two weights include. ~0{;^) As mentioned, later today I'll try to see if my auto mags provide clarification. Regardless, I wish test weight included the weight of the driver--with this weight being given.

[/quote]

smcd

Just out of curiosity, do you encounter driving/acceleration situations frequently enough that it makes constantly keeping your tank near empty worthwhile?

(For the record, the "problem" many people talk about in keeping the tank empty is that, traditionally, you can damage the fuel pump(s) if they don't have a constant flow of fuel. Usually, this is only a problem if you run the vehicle to empty, but on various types of vehicles over the years, it can also be a problem under certain circumstances if the tank is simply near empty, as fuel flow may be interrupted by shifting fuel. However, I don't believe this is really a big issue. On the other hand, I did blow a fuel pump in my E28 528e by running it all the way to empty...)
[/quote]
It surprises me too that anyone would partially fill their tank for performance reasons. In fact, a full tank will have less fluid movement in it and may be better than a half tank for lateral stability. Either way, it's impact is minimal.

The primary reason that I have heard to keep your tank full in cold weather climates is that warm daytime temperatures will add water to the air in the tank. This will will condense when it gets cold (typically at night) and will sink to the bottom causing numerous issues including rust.

In winter, you should try to keep your tank full, particularly if storing the car for a long time. Add fuel stabiliser too of course if storing.

- Sean

znod

Just out of curiosity, do you encounter driving/acceleration situations frequently enough that it makes constantly keeping your tank near empty worthwhile?

(For the record, the "problem" many people talk about in keeping the tank empty is that, traditionally, you can damage the fuel pump(s) if they don't have a constant flow of fuel. Usually, this is only a problem if you run the vehicle to empty, but on various types of vehicles over the years, it can also be a problem under certain circumstances if the tank is simply near empty, as fuel flow may be interrupted by shifting fuel. However, I don't believe this is really a big issue. On the other hand, I did blow a fuel pump in my E28 528e by running it all the way to empty...)
[/quote]
It surprises me too that anyone would partially fill their tank for performance reasons. In fact, a full tank will have less fluid movement in it and may be better than a half tank for lateral stability. Either way, it's impact is minimal.

My tank habits add to the cumulative effect of all the weight-savings things I have done. Overall, the difference is quite significant. Also, I am relatively light. On average, I probably have the equivalent of about 30-35 extra flywheel equivalent HP from weight savings. See Mind Candy ... for more info on weight saving possible with the typical 545i (i.e., ignorning weight savings from body weight and gasoline). If small weight saving don't matter, then tell it to the guys grousing about Danica (or is it Danika?) Patrick. And, having less than half tank of gasoline could easily be the reason for winning a race even in a 545i. Driving typically in town I am unconcerned about lateral stability. I want to be able to go fast straight. And, in this regard, unless I am going to be on a high-speed road, I turn both DSC and DTS off.

The primary reason that I have heard to keep your tank full in cold weather climates is that warm daytime temperatures will add water to the air in the tank. This will will condense when it gets cold (typically at night) and will sink to the bottom causing numerous issues including rust.

I doubt anyone keeps their tank full consistently--wiinter or not--but what you say makes theoretical sense for a winter climate. Fortunately, I live in Phoenix.

In winter, you should try to keep your tank full, particularly if storing the car for a long time. Add fuel stabiliser too of course if storing.

Those actions sound reasonable to me.

- Sean
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das

Oh, I think I misunderstood what you meant. Yes, I'd agree that in tests by automotive publications the weight will be the vehicle as shipped (if they don't use the manufacturer's specified weight).

I thought you were talking about BMW's stated weight, which I was saying is probably the lightest shipping configuration, and thus might explain the disparity.

znod

Oh, I think I misunderstood what you meant. Yes, I'd agree that in tests by automotive publications the weight will be the vehicle as shipped (if they don't use the manufacturer's specified weight).

I thought you were talking about BMW's stated weight, which I was saying is probably the lightest shipping configuration, and thus might explain the disparity.
[/quote]Right. I agree that what BMW states is the weight for the lightest model. And, if someone talks about the curb weight of a BMW without qualification, then they might be referring to the weight of this model, but I don't know.

Do you think magazine curb weight would include the fluids other than any gasoline added for the test? I would think so. But, either way, then what is the difference between curb weight and test weight if the majority of this difference is not gasoline? As mentioned, I wish the difference was at least partially attributable to the driver and that the tester would disclose the weight of the driver. But, logically, one might think that curb weight would include gasoline. Because if there was no gasoline, then how would you get the car to the curb or drive it away from the curb? ~0{;^) Well, of course, I know that you could roll if off a truck next to the curb or, maybe, set it down next to the curb using a helicopter and then add gasoline. I looked in the "big 3" three auto mags, but could not find clarification. I have seen explanations of testing procedures in mags before, but have forgotten mostly what they said and whether they explained the meanings of the various weights. Rambling .... And, I still don't know what "curb weight" and "test weight," as used by the mags, are.

das

Definitions of curb weight:

The weight of an unmanned vehicle without cargo, but including fuel, necessary fluids, and all standard equipment.
www.lake-link.com/dodge/trucktips/glossary.cfm

This means the weight of any vehicle with a full tank of gas but without any load or passengers.
www.thenad.com/cgi-bin/articleman.cgi

Curb weight or kerb weight is the total weight (mass) of an automobile when not loaded with either passengers or cargo. It is generally provided as a statistic about automobile weights, along with gross weight, which represents the weight of an automobile when fully loaded. The difference between gross weight and curb weight is the total passenger and cargo weight capacity of the vehicle.
en.wikipedia.org/wiki/Curb_weight

BimmerGuyFL

I have a feeling that BMW is leaving something out. there is no way i think a 530i is just 44 pounds or so heavier then a 330i. it seems that car and driver when they tested a 530i Sport with a 6 speed manual was 3756 pounds so if they added an automatic it would be closer to 3800 pounds which explains why a lot of magazines and persons when they tested a 530i E60 comparied to a E39 530i mostly said that the E60 felt slugish and it would make sense if it did weigh more. I think BMW should go ahead and re-evaluate there test weights of there cars and add more examples of the car as Base, and Base+premium package, and Base+premium package+Sport Package. I believe this needs to be researched further.

znod

Definitions of curb weight:

The weight of an unmanned vehicle without cargo, but including fuel, necessary fluids, and all standard equipment.
www.lake-link.com/dodge/trucktips/glossary.cfm

This means the weight of any vehicle with a full tank of gas but without any load or passengers.
www.thenad.com/cgi-bin/articleman.cgi

Curb weight or kerb weight is the total weight (mass) of an automobile when not loaded with either passengers or cargo. It is generally provided as a statistic about automobile weights, along with gross weight, which represents the weight of an automobile when fully loaded. The difference between gross weight and curb weight is the total passenger and cargo weight capacity of the vehicle.
en.wikipedia.org/wiki/Curb_weight
[/quote]Thanks Das. Those defs make perfect sense. As mentioned, "but, logically, one might think that curb weight would include gasoline. Because if there was no gasoline, then how would you get the car to the curb or drive it away from the curb?" Do these defs imply that test weight includes the driver and nothing else? Logically, the defs must imply this conclusion and, therefore, one should be able to infer the driver's weight. I'll check this reasoning out on recent 545i tests. The driver will probably end up weighing 500 lbs. ~{;^)

znod

I agree. I'd really like to know what the various options weigh.

300TTto545

Sport pack I am guessing weighs somewhere around 120 pounds. Rim weight and RFTs probably account for 60#. AS - 10#, DD - 40#, seats - 10#.

This would be diff for 530 and 545 b/c of the rim differences.

I read somewhere that DD is not offered on the 3 series because of weight.