9.9 mpg

Remember, with an NA engine, you want to go high throttle (towards WOT) but shift early. This reducethe pumping losses that would be caused by a partially open (mostly closed) throttle (or throttles in the S65's case), and by shifting short, at as low an rpm as possible, you're obviously cycling less fuel through the engine for a given period of time.

So what you're saying is flooring it at 2k would be less efficient than half throttle at 4k?

The relationship as exact as full to 2k is better than half to 4k. Studies have been done that show that using enough gas to get up to speed fairly quickly so you can "shortshift" into the next gear is more efficient than holding the car in the lower gear longer. I suspect the exact throttle levels and shift points vary depending on the engine/gearing/car. Obviously, if you end up in a torque hole in the next lower gear and have to use too much gas to maintain speed in that gear, you are not being efficient. Probably one of the spreadsheet/simulator people could come up with something, but the problem is that it should really be three dimensional and include throttle position if it is to be "real world" as opposed to "looks superficially good on paper to those who don't know better."

I get around 11 mpg...hardly ever floor it. I fill up and the tank lasts me 180 miles.

Thank god my dd last me 300 miles and fills up with regular gas...

Chill72 wrote

To stick to the topic...I drive like a man possessed since there are no cops and no traffic around my area. I average 15 MPG.

15.5 here in the city driving it like I stole it. 9mph seems very low. You dragging concrete around?

TX wrote

15.5 here in the city driving it like I stole it. 9mph seems very low. You dragging concrete around?

Lol. Thts exactly why I'm so confused. Ppl seem to be more aggressive with their cars and yet they still get 12+ mpg's

cwidjojo wrote

So what you're saying is flooring it at 2k would be less efficient than half throttle at 4k?

See pbonsalb's clarification below your post. From idle, as in when you're at a stop, as you begin to accelerate, the most efficient manner to do it in would be to go to WOT as quickly as possible without overpowering the rear tires, and then shortshift (e.g. at 2-3K rpm). The DCT would make this a lot easier as well, but you'd have to always be in manual mode or override by using the paddle.

The reason is that when you're throttle is only partially open, your engine is essentially "fighting" to draw in air, so part of the power it's generating from each power stroke is going towards helping suck that air in past the restrictive throttle. Of course, when you consider that an internal combustion otto cycle has a thermal efficiency of around 25-30%, the high throttle, low rpm-shortshift technique isn't going to make the car significantly more fuel efficient, but it does help and you will see an increase in fuel economy in city, or any heavy start-stop driving.

Mike@Powerchip wrote

9.9 isn't TOO far out of range, given 95% city driving. I highly suggest having the BMW efficient dynamics indicator enabled on your car. That will tell you when to shift, and to what gear. It has increased my MPG dramatically.

There is no reason to go to 3k rpm in city driving. Try shifting at 2300 ish instead.

If all of the proper service hasn't been done, I would suggest doing that as well. Also make sure the tire pressures are in check.

How do we get this on our cars??

stega wrote

How do we get this on our cars??

Through custom coding, and only on 6MTs. I've ordered the necessary cable and I've already got the necessary software -- now all I need is for my car to be built and arrive here to enable that and a laundry list of other options I want, like closing the windows with the remote (not just opening), having only angel eyes as welcome lights and make them fade up rather than just pop on. There's a huge list of possibilities. Check out www dot bmwcoding dawt com if you're curious. If you go to the Beginner's Lounge and read the FAQ section you'll see a link to a Google Doc spreadsheet that lists the popular options.

cwidjojo wrote

can you explain what/how the BMW efficient dynamics indicator work? from what i saw in your video, you were only showing your speed.

Watch it again and pay attention to the far left side of the display. You'll see it starts with two arrows, one pointing up and one pointing down, but as the speed increases you'll notice only the up arrow remains and it displays a number as well, telling the driver "Shift up to 2nd", etc.

TX wrote

15.5 here in the city driving it like I stole it. 9mph seems very low. You dragging concrete around?

+1...I drive mostly in the city and I am getting around 16 mpg...9 mpg?? Ouch..even my old V10 M5 got better mpg!

Something wrong is going on here. Replace your air filter,oil/filter,proper pressures in tires,have dealer look for an aftermarket tune.

I'm getting 15.2mpg around town and canyon blasts. Good luck.

I drove almost 100% city in Boston (sometimes I would hop on Storrow or 90/93), and I always drove it pretty aggressively. If I remember correctly, I was at 12.7 mpg.

I think I average about 12-14 in my City driving.

How much of your time is spent stuck idle in traffic? Even a crawl is better than idle in this car. My last tank which was 99% city driving only got me 160 miles on the tank. A lot of the time I spend stuck in West LA traffic. When my commute was a little longer but I actually was moving, I'd get 200-220 miles to a tank.

WillC310 wrote

How much of your time is spent stuck idle in traffic? Even a crawl is better than idle in this car. My last tank which was 99% city driving only got me 160 miles on the tank. A lot of the time I spend stuck in West LA traffic. When my commute was a little longer but I actually was moving, I'd get 200-220 miles to a tank.

Well I would think a crawl would be better than idle in ANY car seeing as idle by definition is only going to get you 0.0 mpg.

KTM505SX wrote

Something wrong is going on here. Replace your air filter,oil/filter,proper pressures in tires,have dealer look for an aftermarket tune.

I'm getting 15.2mpg around town and canyon blasts. Good luck.

I don't believe that there is anything wrong. I have a 95% city commute, without stop and go, but with red lights/stop signs. When I first got my car, I was averaging 10mpg by easing onto the throttle and shifting before 3K. Since then, I have adjusted my driving style, as referenced above (accelerate hard and either short shift before 3K or shift before 4,500). Now, I am getting about 13-14mpg with nothing else about my commute changing. Basically, this car begs to be driven, so drive it!

Also, I have added one WOT to 8K per day when entering the freeway (on freeway for less than 1 mile) and still see above 13mpg!

Dodge2Dub wrote

I don't believe that there is anything wrong. I have a 95% city commute, without stop and go, but with red lights/stop signs. When I first got my car, I was averaging 10mpg by easing onto the throttle and shifting before 3K. Since then, I have adjusted my driving style, as referenced above (accelerate hard and either short shift before 3K or shift before 4,500). Now, I am getting about 13-14mpg with nothing else about my commute changing. Basically, this car begs to be driven, so drive it!

Also, I have added one WOT to 8K per day when entering the freeway (on freeway for less than 1 mile) and still see above 13mpg!

Yeah, but you have no idea how boston is... My commute mainly is only 3 miles away. And every morning, it takes 2/3 of my daily commute to fully warm up the car. Before then, I change gears below 3k, not wanting to do anything damaging to the car. I don't dare doing WOT before the oil temp reaches at least 3/4. This is probably why I'm getting extremely low mpg

Not to mention, it takes a bitchin long time in the winter to warm up the car

cwidjojo wrote

Yeah, but you have no idea how boston is... My commute mainly is only 3 miles away. And every morning, it takes 2/3 of my daily commute to fully warm up the car. Before then, I change gears below 3k, not wanting to do anything damaging to the car. I don't dare doing WOT before the oil temp reaches at least 3/4. This is probably why I'm getting extremely low mpg

I'd still say driving it quickly up to 3K and short shifting is your best option...just watch out for potholes. I also have the same "problem" on my commute.....2/3 of the commute is below 210 degrees. Luckily, by the time I hit the freeway on my way home, the car is fully warmed allowing for the WOT to 8K!!

I'm very familiar with Boston and still drive a B6 S4 out there (family car, but not the one in my sig...that was the West Coast sled before the E90).