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I just got back from a trip to Jasper Alberta, in the Canadian Rockies. I checked my mileage both directions. By setting my cruise control at 130 KPH (80.77 MPH), I got 10.4 l/100 kms which is 27.2 MPG (imperial) or 22.65 MPG (US). On the way back I got a bit better, 10.3 l/100 kms or 27.4 imperial MPG or 22.82 US MPG. Because of the spring snow storm we just had, I'm still driving on my winter tires.

Travelling from Edmonton to Jasper, it's uphill, starting at 2,200 ft above sea level to ~ 4,000 ft at Jasper. On the return it was downhill, 4,000 to 2,200 ft.

There must be a "sweet spot" for highway speed to get the best gas mileage, but I'm not prepared to drive under the posted speed limit of 110 KPH (68.34 MPH) because I'd get run over. :)

Anyone care to share their experience and wisdom?

BTW, this winter, in the city, with winter tires, I've been averaging about 17.5 l/100 kms or 16.1 imperial MPG or 13.4 US MPG.

With premium gas at $1.29/l or $4.88/US gallon, the fill-ups at $85.00 to $90.00 are starting to hurt. :sad2:

Regards,
Alex
 

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Frankly, if gas is getting expensive for you, you shouldn't own an M5. In Europe they are paying much more.

The gas mileage you got on your trip is really quite good. Remember, this car only claims 21 MPG highway (US), and 13 (US) city.

My car, which normally is ONLY driven on long trips, seems to get better mileage at 85 to 90 MPH. Feathering the throttle will also get you another 0.5 MPG or so.

Consumers' Union says that 48 % of yearly operating costs are depreciation. 21 % gas. If you can figure out how to increase your gas mileage by 10 %, you will only be paying 19 % for gas of your TOTAL operating costs per year. How much is it worth to get 2 % of your annual costs back? (Or, if the price of gas doubles, 4 %.)

Only you can answer that ...

THE BIG "NUT" IN THIS EQUATION IS DEPRECIATION. Something we can do nothing about.
 
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50-55mph would most likely yield the best results, with out driving incredibly slow.
I don't think so in our cars because you need to get into sixth gear and the RPM around 2000. I think that results in around 70 MPH. If you slow down much from there you will need to downshift which will reduce your mileage. I think the speed limit you mentioned is just about right for fuel economy in our cars with the stock differential. Less powerful cars and lower-geared cars will do better at slower speeds.

Do not let the RPM drop much below 2000 because this is hard on the engine if you need to accelerate. I have found that these numbers work well for any gasoline-powered car (around 2000 RPM in high gear for fuel economy). The resulting speed will differ depending on gearing.

To be more specific, the lower RPM limit depends on your need for acceleration. If you want quick acceleration (which requires a lot of power) you need to be up in the RPM band. Spirited drivers will tend to drive in lower gears and higher RPM's. This keeps the engine nicely in the power band and gives the driver a lot of control just with the right foot. Of course, fuel economy is poor when you drive this way, but it is more fun.
 

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I just got back from a trip to Jasper Alberta, in the Canadian Rockies. I checked my mileage both directions. By setting my cruise control at 130 KPH (80.77 MPH), I got 10.4 l/100 kms which is 27.2 MPG (imperial) or 22.65 MPG (US). On the way back I got a bit better, 10.3 l/100 kms or 27.4 imperial MPG or 22.82 US MPG. Because of the spring snow storm we just had, I'm still driving on my winter tires.

Travelling from Edmonton to Jasper, it's uphill, starting at 2,200 ft above sea level to ~ 4,000 ft at Jasper. On the return it was downhill, 4,000 to 2,200 ft.

There must be a "sweet spot" for highway speed to get the best gas mileage, but I'm not prepared to drive under the posted speed limit of 110 KPH (68.34 MPH) because I'd get run over. :)

Anyone care to share their experience and wisdom?

BTW, this winter, in the city, with winter tires, I've been averaging about 17.5 l/100 kms or 16.1 imperial MPG or 13.4 US MPG.

With premium gas at $1.29/l or $4.88/US gallon, the fill-ups at $85.00 to $90.00 are starting to hurt. :sad2:

Regards,
Alex
Your highway milage seems pretty good, particularly at those lower temperatures. I made a 500 mi round trip earlier this week here in California, temps were about mid 50's to low 60's F. I got between 21 and 22 mpg (including some city driving at my destination), with an average speed of about 78 mph. I have noticed that folks outside CA get better milage due to our particular fuel mixture, the winter blend always gives us poorer milage. I agree that speeds under about 70 mph tend to give poorer milage since you need to run in 5th gear for speeds below 60 mph.
At higher temps (80 F), I have seen my milage climb to 23 or 24 mpg at 80 mph.

Boy, your gas prices are high. I thought we were getting ripped here in CA. I know those prices are Canadian $, but I think we are almost at parity due to the weak US dollar. I paid about $4.15 for 91 Octane "Supreme". The Europeans can stop wining about gas prices, as most of the cost is taxes!
 

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85-90 mph is where I have found the best so far. That is on my speedo with 265's on the front, which will make my speedo run about 1.5% high from the already high stock speedo.
 
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Spirited drivers will tend to drive in lower gears and higher RPM's. This keeps the engine nicely in the power band and gives the driver a lot of control just with the right foot. Of course, fuel economy is poor when you drive this way, but it is more fun.
most definitely, when i am in for a 'spirited' drive i am always one gear below... typically in 4th, then give it the beans...
 

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Guys, there is NO WAY the car gets better mileage at 85 than it does at 65. The main variable there is wind resistance, and it is far more at 85.

The S62 motor is perfectly happy trundling along at 1500 rpm, or even a bit less, assuming level pavement. So stick to the speed limit in 6th, avoid variance in speed, and make sure your tires aren't underinflated.
 

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"Boy, your gas prices are high. I thought we were getting ripped here in CA. I know those prices are Canadian $, but I think we are almost at parity due to the weak US dollar. I paid about $4.15 for 91 Octane "Supreme". The Europeans can stop wining about gas prices, as most of the cost is taxes!"

Europeans don't whine, they blockade the motorways and fuel depots.

How does the fact that most of our gas price is tax make it any better?

I filled up my empty tank yesterday and it cost £77!!!!!!!

My heating oil has increased by 30% in cost since January.

These costs are set against a weak dollar, things will get worse if the dollar strengthens.

:grrrrr:
 

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Guys, there is NO WAY the car gets better mileage at 85 than it does at 65. The main variable there is wind resistance, and it is far more at 85.

The S62 motor is perfectly happy trundling along at 1500 rpm, or even a bit less, assuming level pavement. So stick to the speed limit in 6th, avoid variance in speed, and make sure your tires aren't underinflated.
+1.

Dave
 

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This thread is relevant to my interests because we are about to take a trip from DFW to Alexandria, VA for our vacation.

We will go in the beast.

I make some fairly frequent trips to Austin and back, which run about 400 miles or so. I tend to get around 21 mpg running about 80 mph. What appears to matter most with my car is being consistent with the speed no matter what it is.

Could I get a little better mileage running 70 or 65 (yikes)? Maybe so, but I don't want to.

And to be honest, I think that's a pretty good trade-off for speed v. mpg.
 

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This thread is relevant to my interests because we are about to take a trip from DFW to Alexandria, VA for our vacation.

We will go in the beast.

I make some fairly frequent trips to Austin and back, which run about 400 miles or so. I tend to get around 21 mpg running about 80 mph. What appears to matter most with my car is being consistent with the speed no matter what it is.

Could I get a little better mileage running 70 or 65 (yikes)? Maybe so, but I don't want to.

And to be honest, I think that's a pretty good trade-off for speed v. mpg.
+1. As long as you are not lugging the engine, revs matter, so does condition of the motor.

After adding headers and UD pullies, I picked up power all across the rev range, including the bottom. I can easily accelerate from 1500 rpm, as long as I am not calling for hard acceleration. But for cruising or keeping up with traffic for anything approaching normal driving, no problem (also not much fun, but a separate issue:haha:).

I should get about 5-8% better highway mileage because of gearing, maybe abother 1-2% because of better breathing, but at a steady 55 (1500 rpm) I get 30 mpg (driving long enough that slow is tough, like a recovering food addict at an all you can eat buffet!:eek:oohhh:). At 65, I maintain around 28.5, 70 is 27 (2000 rpm) and 80 drops to about 24.5 (2400). Right under 70 seems the best compromise.

This is all steady state cruise, gentle throttle and not too many hills (Florida uses overpasses so the highway patrol has somewhere to hide:grrrr:).

Wind resistance and revs matter. Just try taking a highway cruise at the speed limit, say 70 mph. Drive it in 6th, then try it in 5th. Guaranteed to be better mileage in 6th.

This is not about affording the fuel, simply responding to questions about what kind of fuel economy is available. As some like to say, "drive it like you stole it"!, it is plenty of fun!!:thumbsup:

Regards,
Jerry
 

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Guys, there is NO WAY the car gets better mileage at 85 than it does at 65. The main variable there is wind resistance, and it is far more at 85.

The S62 motor is perfectly happy trundling along at 1500 rpm, or even a bit less, assuming level pavement. So stick to the speed limit in 6th, avoid variance in speed, and make sure your tires aren't underinflated.
I respectfully disagree, not only based on empirical experience, but on engineering. Any Mech-Es here want to correct me? The premise is like this:

On a manual transmission car, your mileage is fixed depending on the RPM and gear. It doesn't matter if you have a 100mph tailwind or a 100mph headwind, uphill or downhill. If your engine is powerful enough to overcome the wind resistance at a given speed without you downshifting, then at a given speed, since there is a direct mechanical linkage between the engine and rear wheels, if the injectors are squirting the same amount of fuel on each firing, then you're going to get the same mileage no matter what else is going on in a certain gear.

That having been said, by definition, an engine is most efficient when it's providing the most torque. Thus: sixth gear, highest torque = best mileage, regardless of outside conditions. For us, I believe that's about 4000 revs, which is, what, about 100mph?

My personal experience is that I get about 18mpg at 55, 21mpg at 80, and 24 at 100, conducted over a long trip from San Diego to Vegas. On a one year, daily, 160-mile commute, averaging 85mph, I got 22mpg.

The entire "driving 55 will save you gas" argument is completely bogus for our vehicles. For your average four-banger with highest "torque" at 2500rpm, which doesn't have enough power to overcome wind resistance above 70 without downshifting, then sure, 55 will save you gas. It simply is not the case in our Beasts.
 

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Guys, there is NO WAY the car gets better mileage at 85 than it does at 65. The main variable there is wind resistance, and it is far more at 85.

The S62 motor is perfectly happy trundling along at 1500 rpm, or even a bit less, assuming level pavement. So stick to the speed limit in 6th, avoid variance in speed, and make sure your tires aren't underinflated.

I agree with this 100% and it works. However, if you are really concerned about getting 2 or 4 mpg more, you should have purchased a 530. Sorry, don't mean to be rude. Maybe it's an fyi question. I suppose there is an optimum rpm/mpg figure but it's usually does not always corrolate to a reasonable speed. I've read the optimum speed medium is where the torque and hp meet. Don't know how true this is though. The tradeoff of fun for mpg is a no brainer. I'll always take the fun factor in the M. Isn't that the point of purchasing an M anyway? :hihi: Just drive and have fun!
 

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Perhaps some forgot to realize this, but gas is an issue for a lot of us. Especially some of us younger ones. When we got the car, were able to deal with gas prices. There was a pinch, but it was manageable. But now it's increasing a hell of alot really fast to the point where it's REALLY HURTING and messes up with our planned gas budget for the car.

It would be like the price of parts going up 50% in 6 months and then when you ***** about it, someone tells you "oh well it's a BMW, you should know that parts are more expensive than Honda's."
 

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My recent 2000 mi plus trip yielded the best mileage at 80 mph on cruise. There was a difference in a fill-up of roughly 20/22$ between Canadian and US prices. This was in early April using the highest octane pump gas available..(94 in Canada/93 in US)..I think the best way to maximize mileage is to ensure all the filters, plugs, and tire pressures are correct and go...If there is an issue with fuel costs, then maybe some should consider a vehicle change..There are a ton of options out there...But nooooM5 is ever going to be a mileage car..Ever
 

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Frankly, if gas is getting expensive for you, you shouldn't own an M5.
Yep.

I also tell people if the price of gas if creating problems for you, you have a lot BIGGER things to worry about in your life if you can afford an extra $200 a month for gas!!
 
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Cruising in 6th around peak torque will help the best(80mph).
 

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I respectfully disagree, ...

... by definition, an engine is most efficient when it's providing the most torque. Thus: sixth gear, highest torque = best mileage, regardless of outside conditions. For us, I believe that's about 4000 revs, which is, what, about 100mph?

...

The entire "driving 55 will save you gas" argument is completely bogus for our vehicles. For your average four-banger with highest "torque" at 2500rpm, which doesn't have enough power to overcome wind resistance above 70 without downshifting, then sure, 55 will save you gas. It simply is not the case in our Beasts.
I am not an engineer but have engineering training (including being an engineering major in college before changing majors). "... an engine is most efficient when it's providing the most torque" ... that is my understanding. I'm not sure 4,000 is the max torque, but since we have a very flat torque curve, 3,000 RPMs (87 MPH in 6th) is close enough for me. And, I have tried it many times. I can watch my instantaneous mileage rise as I go from 60 to 80 MPH (in central California at 6 AM).

Why not travel at 600 RPMs? You would get incredible mileage, but it would take a week to get across town.

I would think that the BMW corporation, which also builds cars for Germany, where there are currently no speed limits outside of towns, would focus on better mileage at higher speeds. Unfortunately, with traffic, hills, and other diversions, it is difficult to do a proper test.
 
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