The joys of driving with 1-bar-left tank.

[VinceLA]

All,

I thought this could bring up some interesting discussion. I don't think I have read anything closely related yet.

But I am sure by now, most of you have realized that the smart feels faster off the line when the tank is 1-bar-left compared to full tank. Strange as it may sound, I actually look forward to driving the smart more when it has less than half a tank. I can really feel the enhanced acceleration through the corners as well. Today, I filled her up til half a tank. And I love it. Half-a-tank still drives better than a full-tank.

Since the weight of a gallon of gasoline varies according to temperature, let's just say a nominal 6lb per gallon at some given temperature ( I think maybe 20C, can someone confirm this?). Our tank holds about 9 gallon ~ 54lbs.

Half a tank ~ 27lbs.

1 bar left (presumably around 1.0 gal left) is 6lbs.

Losing 54 - 6 = 48lbs transform the smart into a different car, IMO. To me it's a night and day difference.

After market exhaust apparently shaves about 10lbs? No one has posted the official DTH, CES weight numbers...

The question I have is...where else can we shave off 48lbs with a full tank of gas? Lighter alloy wheels?

[unicycle]

Is 27 lbs really that significant that you can feel the difference? It's only 1.5% of the car's weight.

Gasoline doesn't weigh appreciably more or less depending on temperature. It's not like ppl are filling up with hot gasoline.

If my car suddenly weighed 1.5% less, I don't think I could tell if it went 1.5% faster or drove 1.5% better or accelerated 1.5% more easily. I couldn't even tell if it got 1.5% better mileage, and I'm pretty obsessive about that. I just doubt that most ppl could feel the difference, but there are always princesses out there who complain about lumpy mattresses and evil queens walking around with bagful of peas to bother them with....

[Aerotaz]

I feel the same way, but thought it was adrenaline!

[WickedMessenger]

If this forum has taught us anything, it's that people will believe what they want to believe, whether flying in the face of logic or the plain facts.

[dbarrans]

Originally Posted by VinceLA

...where else can we shave off 48lbs with a full tank of gas?

I lost 60 lbs about five years ago; all it takes is the right motivation. Maybe that would work for you. :-)

- dan

[curtis]

3 years ago I lost 120 lbs and i didn't notice any difference in my cars performance.

[DFWehman]

Maybe we can figure out how much weight loss is required to feel a perceptable performance change. If 120 is not enough, maybe 240? 360? !! We could get a dyno! No doubt there's a change, less mass to accelerate. but it seems people aren't "feeling it".

[unicycle]

Originally Posted by DFWehman

Maybe we can figure out how much weight loss is required to feel a perceptable performance change. If 120 is not enough, maybe 240? 360? !! We could get a dyno!

I'm thinking: helium. A few thousand luftballons (far more than 99) ought to do it.

[DFWehman]

In a word ... understeer!

[Woody14619]

I could feel the difference in my old Saturn between a full/half/empty tank, but haven't fully adapted to my smart yet. I never thought it had much to do with weight as much as it did with the fact that it was liquid sloshing around. Liquid had different inertial properties than a solid metal car. It may be I feel it less since the tank in this car is under-seat vs. being back toward the trunk more? Or that it's just smaller by 50%?