I've been wondering if shifting into Neutral when coasting down a hill in your BMW is a good or bad idea? It seems that opinion is mixed as to whether or not it causes harm to the vehicle, especially if you take your foot off the gas when you shift into N and then back into D.
I have noticed in my X3 3.0si that since the vehicle comes equipped with Hill Descent Control that the engines rpms are around 2750 to 3000 when descending at say 70mph, resulting is the car using almost as much fuel as if it were driving on a level road. At the same time I noticed the X3 can make it up grades as steep as 30% without up shifting which is impressive as it holds 65 or 75mph.
I have noticed that the X3 gets roughly 22mpg driving normally not caring about gas, and speeding where possible such as 74 in a 65 or 69 in a 60 or 84 in a 75. Yet on a drive home which was roughly 300 miles that included some steep mountain hills that went from 2,000ft to 5,000 to 3,000 to 1,000 to 2,000 and so on over the duration of the drive, I decided to shift into Neutral when descending these inclines. The result:
An amazing 28mpg average, 5mpg more on average for 300 miles is significant. Considering I would use roughly 12 gallons, that amounts to 50 extra miles, an easy savings of $15 and a good 3 gallons less consumption which is better for the environment. All of this raises the question[???1], is it harmful or not?
I have noticed in my X3 3.0si that since the vehicle comes equipped with Hill Descent Control that the engines rpms are around 2750 to 3000 when descending at say 70mph, resulting is the car using almost as much fuel as if it were driving on a level road. At the same time I noticed the X3 can make it up grades as steep as 30% without up shifting which is impressive as it holds 65 or 75mph.
I have noticed that the X3 gets roughly 22mpg driving normally not caring about gas, and speeding where possible such as 74 in a 65 or 69 in a 60 or 84 in a 75. Yet on a drive home which was roughly 300 miles that included some steep mountain hills that went from 2,000ft to 5,000 to 3,000 to 1,000 to 2,000 and so on over the duration of the drive, I decided to shift into Neutral when descending these inclines. The result:
An amazing 28mpg average, 5mpg more on average for 300 miles is significant. Considering I would use roughly 12 gallons, that amounts to 50 extra miles, an easy savings of $15 and a good 3 gallons less consumption which is better for the environment. All of this raises the question[???1], is it harmful or not?