( 
)This guide is addressing the guide titled How I get 30-34mpg on a 1999 bmw inline-6, 328i
OMG, this is bad advice... everything he says here is wrong... Every study shows that keeping a consistent speed is the most fuel efficient means of getting from A-B. At best, I can believe this guy is deceiving himself. If he is, in fact, getting better fuel mileage than his peers, he is probably just accelerating more slowly than those peers... At worst, he is putting one over on Ebay. I won't bother going over the exquisite details but, physics is the basis of my argument... Air resistance aside, the energy required to accelerate is proportional to the square of the relative change in speed / time used to change speed.. Add to that the always present air resistance. The energy required to move at increasing speeds is proportional to the cube of the difference in speed. So, lets say he hopes to average 60 mph, the energy required to travel at 70mph is so very much more than what is saved at 50 mph that it will never work out to be better than maintaining a steady 60mph. His point that the gravitational assist from going down hill will only help make the total energy requred to go up and down hills improve from shockingly bad to just bad...
He admitted that driving as he advocates in traffic is a dangerous act... I worry that other drivers listening to his advice may use looser standards. If so, they could become driving hazards...
So, please please please do not heed this guy's advice... It will NOT save you on gas consumption. It may make you a road hazard.
If you want to save gas, use your car less. Plan your trips so you can get as many errands done at once as possible. Avoid rush hour when possible... In short, if you think about your trips, you will save gas. Taking this guy's advice will cost you more in gas.
OMG, this is bad advice... everything he says here is wrong... Every study shows that keeping a consistent speed is the most fuel efficient means of getting from A-B. At best, I can believe this guy is deceiving himself. If he is, in fact, getting better fuel mileage than his peers, he is probably just accelerating more slowly than those peers... At worst, he is putting one over on Ebay. I won't bother going over the exquisite details but, physics is the basis of my argument... Air resistance aside, the energy required to accelerate is proportional to the square of the relative change in speed / time used to change speed.. Add to that the always present air resistance. The energy required to move at increasing speeds is proportional to the cube of the difference in speed. So, lets say he hopes to average 60 mph, the energy required to travel at 70mph is so very much more than what is saved at 50 mph that it will never work out to be better than maintaining a steady 60mph. His point that the gravitational assist from going down hill will only help make the total energy requred to go up and down hills improve from shockingly bad to just bad...
He admitted that driving as he advocates in traffic is a dangerous act... I worry that other drivers listening to his advice may use looser standards. If so, they could become driving hazards...
So, please please please do not heed this guy's advice... It will NOT save you on gas consumption. It may make you a road hazard.
If you want to save gas, use your car less. Plan your trips so you can get as many errands done at once as possible. Avoid rush hour when possible... In short, if you think about your trips, you will save gas. Taking this guy's advice will cost you more in gas.
Guide created: 05/07/06 (updated 16/07/07)
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