3 ms·

I’ve seen some people keep the tank only partially full because it improves performance (the car will be more efficient if it is lighter and might eg handle bet

I’ve seen some people keep the tank only partially full because it improves performance (the car will be more efficient if it is lighter and might eg handle better too, especially if it is a small car) though I don’t really buy that argument. But if you supposed that everyone drove normally until their tank was 1/8 full then refuelled to the top, the average tank would be 7/16 full so if lots of people refuel all at once that is 9/16 times a lot of fuel tanks.

WaltPurvis 5y ago
That argument seems ridiculous. Gasoline weighs 6.3 pounds per gallon and most cars have 15-20 gallon tanks, so if you keep your tank around half-full your car will be lighter by maybe 50 or 60 pounds. Any performance improvement from that would be imperceptibly small.
- gifnamething 5y ago
  Sorry but this is just wrong. The difference in feeling after filling up a small car from empty is significant just for normal driving. Look at what people pay for making sports cars lighter - 50 pounds is a lot!
  - WaltPurvis 5y ago
    Even small cars weigh thousands of pounds. Fifty pounds is objectively not a lot. If you're trying to tell me you can tell a significant difference in performance and handling in a car with a 7-year-old in the backseat versus no 7-year-old in the backseat, well, I don't believe you at all.
    - gifnamething 5y ago
      I can feel that too. Or a suitcase in the back. It's absurd you're telling me I haven't experienced this. Luckily I don't have to be concerned with what someone who can't notice that believes: it falls to you to explain why there are so many lightweighting products on the market. Why do BMW offer a carbon roof that reduces weight by 5kg? Why did pre-refill-ban F1 only do partial refills? Why do rally co-drivers sit lower than the drivers?
      - deleted 5y ago
        [deleted]
spuz 5y ago
> But if you supposed that everyone drove normally until their tank was 1/8 full then refuelled to the top, the average tank would be 7/16 full so if lots of people refuel all at once that is 9/16 times a lot of fuel tanks. Sorry, extremely minor nit-pick but I think the fractions go the other way. The average tank should be 9/16 full leading to 7/16 of a tank extra per person.
- dan-robertson 5y ago
  Yeah you’re right. I should have realised it doesn’t make sense for the numbers to be in that order relative to each other.

WaltPurvis 5y ago

That argument seems ridiculous. Gasoline weighs 6.3 pounds per gallon and most cars have 15-20 gallon tanks, so if you keep your tank around half-full your car will be lighter by maybe 50 or 60 pounds. Any performance improvement from that would be imperceptibly small.

gifnamething 5y ago
Sorry but this is just wrong. The difference in feeling after filling up a small car from empty is significant just for normal driving. Look at what people pay for making sports cars lighter - 50 pounds is a lot!
- WaltPurvis 5y ago
  Even small cars weigh thousands of pounds. Fifty pounds is objectively not a lot. If you're trying to tell me you can tell a significant difference in performance and handling in a car with a 7-year-old in the backseat versus no 7-year-old in the backseat, well, I don't believe you at all.
  - gifnamething 5y ago
    I can feel that too. Or a suitcase in the back. It's absurd you're telling me I haven't experienced this. Luckily I don't have to be concerned with what someone who can't notice that believes: it falls to you to explain why there are so many lightweighting products on the market. Why do BMW offer a carbon roof that reduces weight by 5kg? Why did pre-refill-ban F1 only do partial refills? Why do rally co-drivers sit lower than the drivers?
    - deleted 5y ago
      [deleted]

spuz 5y ago

> But if you supposed that everyone drove normally until their tank was 1/8 full then refuelled to the top, the average tank would be 7/16 full so if lots of people refuel all at once that is 9/16 times a lot of fuel tanks. Sorry, extremely minor nit-pick but I think the fractions go the other way. The average tank should be 9/16 full leading to 7/16 of a tank extra per person.

dan-robertson 5y ago
Yeah you’re right. I should have realised it doesn’t make sense for the numbers to be in that order relative to each other.