Fuel Economy Predictions?

[mkoesel]

Thanks for posting the information and providing explanations Stav and mdss6.

[cpippolo]

Very disappointing. May not be able to go a week without filling up. If its 24 for the manual I'm probably out at this point.

[Walt Dockery]

Originally Posted by stressdoc

If this follows convention the 26 is for the

standard, i.e., manual; (24) is for optional DCT.
But who knows. And who knows what this means for real life driving.

Bit of a disappointment relative to 335: 22 / 32

But is the DCT considered optional?

On the online configurator, the DCT is automatically selected as the default and a box is later checked if you want the manual, taking $2900 off the cost. The way they have it set up, seems to me DCT is standard and manual is a negative cost "option".

I hope I'm wrong, I plan to get the 6MT.

[mdss6]

Originally Posted by Walt Dockery

But is the DCT considered optional?

On the online configurator, the DCT is automatically selected as the default and a box is later checked if you want the manual, taking $2900 off the cost. The way they have it set up, seems to me DCT is standard and manual is a negative cost "option".

I hope I'm wrong, I plan to get the 6MT.

Well, they certainly aren't as clear as they could be about which transmission has which rating. But for point of reference, the M5/6 is rated 2 MPG lower with the M-DCT than with the manual. And the transmissions have approximately the same relative ratios in the M5/6 as they do in the M3/4. Just based on this, it is a good guess the manual in the M3/4 has the same 2 MPG advantage.

I've not researched the experience of the M5/6 community, but I'm now curious to know if they observe any such difference when taking long trips? The combined number is approximately the same in either case, so I doubt there is a difference in most daily driving. But I'd like to know if one has longer legs on the interstate/autoroute/autobahn?

Regards

[mkoesel]

Originally Posted by Walt Dockery

On the online configurator, the DCT is automatically selected as the default and a box is later checked if you want the manual, taking $2900 off the cost. The way they have it set up, seems to me DCT is standard and manual is a negative cost "option".

That just means they are pushing the DCT. If it were standard, the base price would be $2900 more and the MT would be a no cost option (like with most other BMWs). If you ignore the online configurator and just look at the pricing guide, there is no ambiguity whatsoever - MT is listed as standard equipment and DCT is listed under optional equipment.

[GregW / Oregon]

Originally Posted by mdss6

Per the last sentence of that paragraph:
"However, the combined city and highway fuel economy that is used to determine tax liability is not adjusted to account for in-use shortfall, so it is higher than the mpg values provided in the Fuel Economy Guide (www.fueleconomy.gov) and posted on the window stickers of new vehicles."

There are no cars that I am aware of with window stickers of 17/26 (or even 17/24) that have a gas-guzzler tax.

The EPA updated its testing system a few years ago with the intent to make window stickers more realistic. But it was only used to update window stickers. The testing system which generates fuel economy numbers for CAFE and gas-guzzler caluculations is different and gives higher results. I believe this is a major reason why the industry has not protested the large planned increases in CAFE as they aren't as large as they appear on the face of it. I'd be curious to know the numbers produced by this different regulatory scheme, but I suspect they are much closer to the EU numbers (which almost universally reflect much higher mileage than US window stickers).

Bottom line(s).
- The 22.5 combined number in the gas-guzzler reg is not calculated the same way as the window sticker combined number and they aren't directly comparable.
- The new M3/4 gets better mileage than other cars which are not gas-guzzlers and should not be one.
- If the maual gets 2 MPG better on the highway (26 vs 24), this is a surprising result as the taller top gear in the M-DCT would seem to predict the opposite. Does the M-DCT have significantly higher friction/losses? How else to explain? Well, other than explaining it by the manual being the number in parenthases (24).

Regards

That was what I was trying to get at in my post #267,

[Carl L]

Pretty dreadful fuel economy for a 3000cc engine in 2014, especially when compared to more powerful AMG Mercedes (all stats in US gallons and from MB.com and BMW.com):

-The E63 with a bi-turbo 5.5L with 550bhp and Four Wheel Drive manages 16 and 23.

-The SLK55, with a 5.5L V8, manages 19 and 28.

-Porsche aren't great with MPG yet even the 400bhp 3.8L 911 S does 20 and 27.

So 16 city is the same as the heavy, more powerful 4WD E63. The biggest issue though is that doing 24 mpg when taking a long trip means range is again going to greatly disappoint. Considering the pathetic range of the E9x, this really is a very poor showing from BMW.

[Stevens21234]

I'll have to retract my earlier gas guzzler statements.

As discussed previously, the MPG used to calculate gas guzzler tax is different than the EPA MPG label numbers (by a factor of about 1.25 to 1.3).

I can determine this by comparing cars applicable to gas guzzler here (see the M3 convertible combined MPG of about 20.8 calculated for gas guzzler):

http://www.epa.gov/fueleconomy/guzzler/420b13037.pdf

to EPA sticker fuel economy here for the M3 convertible (16 MPG):

http://www.fueleconomy.gov/feg/Power...le&srchtyp=ymm

F80 will have a combined gas guzzler calculated MPG of about 26 (assuming combined MPG of 20), above the 22.5 threshold needed to bypass the gas guzzler tax. The 26 is NOT what users will be experiencing as the combined 20 mpg on the sticker is used to reflect that.

I'm happy there's no tax, but still disappointed in the numbers. See article here where BMW communicated to the author the car would get 26 combined for manual and 28 combined for DCT:

http://www.autoweek.com/article/2014...iews/140509868

[GregW / Oregon]

Originally Posted by Stevens21234

I'm happy there's no tax, but still disappointed in the numbers. See article here where BMW communicated to the author the car would get 26 combined for manual and 28 combined for DCT:

Likely citing European numbers.

[mkoesel]

Originally Posted by Carl L

The biggest issue though is that doing 24 mpg when taking a long trip means range is again going to greatly disappoint. Considering the pathetic range of the E9x, this really is a very poor showing from BMW.

I strongly suspect that, with this particular car, burning through a tank in high gear at legal and quasi-legal speeds will net you better than the advertised highway number. In any case with the ~16 gallon tank we are talking about a minimum range of 400 miles in this scenario which is already doing much better than the E9x's low 300's that most could achieve as a best case. And it would not surprise me at all to eventually see reports of 450 miles or perhaps even more.

[Brosef]

Originally Posted by Brosef

I've noticed a number of you guys are confusing mileage with consumption. as someone pointed out already on this forum, a decrease in consumption is worth more than just the same percentage increase in mileage. here's the quick math:

e90 M3 (highway, then city):

20 miles / 1 gallon = 20 mpg
14 miles / 1 gallon = 14 mpg

if consumption decreases by 25%, that means that to go those same distances, you need 25% less fuel. so, in both instances, you only need 0.75 gallons. let's rerun the math

20 miles / .75 gallons = 26.7 mpg
14 miles / .75 gallons = 18.7 mpg

the 17 city figure definitely seems low relative to BMW's claim that the new car is 25% more efficient. but it looks like the highway number is quite close. see my previous calculations above.

[Carl L]

Originally Posted by mkoesel

I strongly suspect that, with this particular car, burning through a tank in high gear at legal and quasi-legal speeds will net you better than the advertised highway number. In any case with the ~16 gallon tank we are talking about a minimum range of 400 miles in this scenario which is already doing much better than the E9x's low 300's that most could achieve as a best case. And it would not surprise me at all to eventually see reports of 450 miles or perhaps even more.

I hope you are right, I really do. 450 miles would be acceptable, 400 is still on the low side given that when I'm taking long trips the only reason I stop is to fill the car's tank not empty mine.

[solstice]

Originally Posted by mkoesel

I strongly suspect that, with this particular car, burning through a tank in high gear at legal and quasi-legal speeds will net you better than the advertised highway number. In any case with the ~16 gallon tank we are talking about a minimum range of 400 miles in this scenario which is already doing much better than the E9x's low 300's that most could achieve as a best case. And it would not surprise me at all to eventually see reports of 450 miles or perhaps even more.

I agree, it's always been like that. Our Cayenne for example with it's 3.6 l NA engine, AWD drivetrain and relative to cars poor aero gets close to 30 mpg on cruise control at 70 mph while rated at 23 mpg. My E90 M3 gets 25 mpg while rated at 20 mpg. I think the F8X will easily cruise at 30 mpg on the hwy. The DCT however does not "sail" like modern torque converters, it's fully engaged all the time which saps gas compared to say an ZF 8 speed 335i otherwise I would think 35 mpg would be possible at hwy for the F8X on cruise control.

However when you drive the car you can't expect it to be responsive and generate big power at any rpm without burning some more fuel. Absolutely no surprise here. Just as expected.

[Sir Loin]

Originally Posted by mkoesel

I strongly suspect that, with this particular car, burning through a tank in high gear at legal and quasi-legal speeds will net you better than the advertised highway number. In any case with the ~16 gallon tank we are talking about a minimum range of 400 miles in this scenario which is already doing much better than the E9x's low 300's that most could achieve as a best case. And it would not surprise me at all to eventually see reports of 450 miles or perhaps even more.

Originally Posted by solstice

I agree, it's always been like that. Our Cayenne for example with it's 3.6 l NA engine, AWD drivetrain and relative to cars poor aero gets close to 30 mpg on cruise control at 70 mph while rated at 23 mpg. My E90 M3 gets 25 mpg while rated at 20 mpg. I think the F8X will easily cruise at 30 mpg on the hwy. The DCT however does not "sail" like modern torque converters, it's fully engaged all the time which saps gas compared to say an ZF 8 speed 335i otherwise I would think 35 mpg would be possible at hwy for the F8X on cruise control.

However when you drive the car you can't expect it to be responsive and generate big power at any rpm without burning some more fuel. Absolutely no surprise here. Just as expected.

I am thinking about the same thing. With so much low end torque, one should be able to short shift at 3K RPM from 1st to 7th (or 6th with MT) and quickly get to highway cruising speed without much effort from the engine.

[stressdoc]

My thoughts: My E90 gets about 30mpg highway; with smaller tires I was able to get 32 mpg.

The F80 has wider stickier tires, more aero resistance, hence I guesstimate 28mpg cruising about 75mph.

I have switched my order back to manual tranny.

[khanyam4]

Originally Posted by Carl L

Pretty dreadful fuel economy for a 3000cc engine in 2014, especially when compared to more powerful AMG Mercedes (all stats in US gallons and from MB.com and BMW.com):

-The E63 with a bi-turbo 5.5L with 550bhp and Four Wheel Drive manages 16 and 23.

-The SLK55, with a 5.5L V8, manages 19 and 28.

-Porsche aren't great with MPG yet even the 400bhp 3.8L 911 S does 20 and 27.

So 16 city is the same as the heavy, more powerful 4WD E63. The biggest issue though is that doing 24 mpg when taking a long trip means range is again going to greatly disappoint. Considering the pathetic range of the E9x, this really is a very poor showing from BMW.

I agree

[bdoooh]

Looks like the MPG figure is out on BMWUSA's site!

[GregW / Oregon]

Originally Posted by bdoooh

Looks like the MPG figure is out on BMWUSA's site!

As noted in post #256, thanks.

[pebblebeachguy]

So is the 26 MPG Hwy for DCT or manual?

[Vectors2final]

Not great.... not terrible.

Fine by me. MPG is not exactly a priority when buying a performance car.

[ake]

Originally Posted by pebblebeachguy

So is the 26 MPG Hwy for DCT or manual?

The homepage doesn't directly say.

And as I don't understand how the EPA figures are tested (for me every day a new hint comes up but I haven't solved the puzzle yet) only an assumption can be made: 26 for the DCT, 24 for the manual.
Why? Because of the EU ratings where DCT uses .5 liters less than the MT.

And I know that could be the wrong comparison... if that is the case I'm sorry!
One more hint: The M5 states 20 MPG on the BMWUSA, and according to the fueleconomy.gov, this is the figure for the DCT. So if I use that as measurement, the 26 should count for the DCT at M3/4 as well.

[pebblebeachguy]

Perhaps the DCT having 7 gears vs 6 in the manual gives it a higher efficiency overdrive like advantage for fuel economy.