[Debaser]

This winter I put on a new set of winter tires (1" smaller than my regular 18" summers) and was surprised that my mpg shot up by about 10mpg. I figured it was a fluke or had something to do with not recalibrating the system to smaller wheels or whatever...

But now it's been several months since I've had my original 18" summers back on and I consistently get over 40mpg on the highway. I've never bothered to run on a full of gas to see if I'm really averaging that much, but I have no reason to doubt it. In fact, I make five 80 mile roundtrips every week to work (400 miles total) each week and that usually takes me exactly one tank.

Not sure what to make of this...

It's a 2008 328i with about 40k miles on the odometer.

[BMWUltimateDriv3r]

pics for proof

[John 070]

sigh....

[tmo24]

Coasting downhill in neutral?

[Bighorns]

Which gauge are you looking at, the digital, or the dial gauge? The digital gauge is an over-all average, and the dial gauge is what the car is doing right at that moment. My car will peg the dial gauge, and jump well over 47 on the digital when going downhill, but it all averages out to around 30 MPG hwy. when all is said and done.

[Hisam135i]

whats so shocking... i drive a lot of free way and my 335i can get 450 miles to the tank if not more if i pushed it ...just depends on your driving style cruise control is your best friend when increasing MPG

[Seminole]

Originally Posted by Debaser

But now it's been several months since I've had my original 18" summers back on and I consistently get over 40mpg on the highway. I've never bothered to run on a full of gas to see if I'm really averaging that much, but I have no reason to doubt it. In fact, I make five 80 mile roundtrips every week to work (400 miles total) each week and that usually takes me exactly one tank.

Not sure what to make of this...

It's a 2008 328i with about 40k miles on the odometer.

Some simple math shows you're not getting 40mpg. Our cars have about a 16 gallon tank, so 400 miles divided by 16 = 25mpg....

You're in Canada so I don't know if you're messing up the conversion somehow, but to get 40 US mpg you'd have be getting about 5.8L per 100km.

[SixShotEspressO]

Originally Posted by Hisam135i

whats so shocking... i drive a lot of free way and my 335i can get 450 miles to the tank if not more if i pushed it ...just depends on your driving style cruise control is your best friend when increasing MPG

Im gonna have to call BS on this one. are you hyper mileing? seriously 450 miles per tank? thats 335d territory.

[roadkillrob]

Don't forget he is in Canada, if he is using an imperial gallon to calculate, 40mpg to an imperial gallon is 33mpg to a US gallon which is obtainable for a 328i on the highway.

One question would be how are you calculating - from actual fuel burned or using the car computer?

[bbbuzzy]

"Which gauge are you looking at, the digital, or the dial gauge?"

The gauges are all over the map and really are just an approximation. Also, only the '06 models like yours and mine have the dial gauge, this was replaced by a temp gauge in later years. So, using the digital gauge for your average mpg gets you close to the real number. If you really want to know, fill it up, mark the miles, drive it to near empty and fill it up again at the same pump, mark the miles again and do the math (total miles driven divided by gallons used)= MPG. Good luck, I'm betting 45mpg is just a calibration issue with your car. No way you're getting that high an average.

[Seminole]

Originally Posted by SixShotespress0

Im gonna have to call BS on this one. are you hyper mileing? seriously 450 miles per tank? thats 335d territory.

Not really. 450 miles on a 16 gallon tank is 28.15mpg. 328i's are rated at 28 or 29 on the highway, so 450 is entirely reasonable. the longest highway trip I've made in my 328 was 475 miles and I made it to my destination with about 1/16th of a tank left.

I'm sure that a 335i driven conservatively could probably hit those same figures.

[Jadar]

Originally Posted by SixShotespress0

Im gonna have to call BS on this one. are you hyper mileing? seriously 450 miles per tank? thats 335d territory.

The 335d should be seeing 550-600 to a tank. If youre getting less then that something is wrong. I squeezed out 412 miles once on my tank mostly highway tho. I saw 31.9mpg.

On average I see 350-375 to the tank and I average 24.7-25mpg.

[GetSomeE92]

45 mpg is great.

I get pretty good mileage from the 335i as well. On highway trips my range will often exceed 500 miles. I always run into traffic at some point, though, so it drops. Florida is nice and flat, so no hills to combat.

[anerbe]

Is your commute downhill both ways?

[Coolieman1220]

Originally Posted by dd1981

The 335d should be seeing 550-600 to a tank. If youre getting less then that something is wrong. I squeezed out 412 miles once on my tank mostly highway tho. I saw 31.9mpg.

On average I see 350-375 to the tank and I average 24.7-25mpg.

i've gotten as high as 40, checked at the pump in slow heavy traffic moving slow, like 60-65mph, i usually get between 32-35.

[1NS0MN1A]

Cruise controlling 68MPH on my car, My car has show 600 miles to next fillup, and I was able to do 520 of those miles before filling up.

[DUI Elite]

Am I the only one seeing

40 miles.......16 gallons
-----...x...---------.....= 640 miles
gallon...........1

?? Simple math..

450 miles..........1................28.125 miles
---------....x...-------......=..------------
1.................16 gallons........1 gallon

If you're not getting at least 600+ miles, you're not even close to 40 mpg..

Best I ever got in my 325 is 32 mpg going 55 mph on cruise control across Illinois (very flat highways).

[55]

Our (canadian) computers show L/100km, not MPG. Did you recalculate it for this post?

[AddictedToBavarian]

What? I frikin average 18!

[WingZeroX5]

I can somewhat backup his claim...

I drove back and forth from MA/NH to NY a few times already. Depending on my driving style and speed and RPM's, I could average 40's. This is calculation based on leaving traffic, so outside of the Bronx in NY. I don't leave from Boston so traffic is non existant for me in the MA/NH side.

I usually avg about 37 MPG. One way trip is about 240 miles, uses half a tank of gas, about 80mph.

Assuming that I fill up 13 gallons for the trip (remember, I have half a gallon left and I let the needle approach the last 2/16th of the needle, just when the chime coems on that you're low on gas), this trip in particular averaged about 42mpg.
Here's a pic I took after filling up from Shell and still got about an hour or so left of driving. Sorry if it's huge...and blurry, it says the range left is 540miles. I used cruise and took over whenever necessary. A LOT of pedal discipline and barely went over 75mph, mostly around 65-70mph range.

[Tom K.]

Some info is missing here.

While the OP never specified how much gas was used to travel the 400 miles, if we assume that he/she filled up when reserve light came on, that would mean about 14 gallons, or 28.5 mpg. Both my 128i and 328i do better than that at steady cruising speeds.

So how many gallons (or liters) were used to travel the 400 miles? And if gallons, was the OP using Imperial or US gallons?

Tom

[fatass]

trololololol

OP can't do math