[ShadyShifty]

Hi all, I purchased my 328i in Florida a month and a half ago, and I've noticed that since I've moved it back to WV, I've been getting much poorer fuel economy.

Then it hit me, did the Florida dealership perhaps use a higher viscosity oil that isn't suitable for West Virginia's winter conditions?

I reset the trip information prior to my trek home, for which I achieved a 29.7 MPG fuel economy. Of course this was 99% highway, but I'm just using this to show that my car is capable of the EPA estimate, at least for highway use.

Where it falls short is around the city. I'm achieving 15-16 MPG, and I'm certainly not an aggressive driver. I've noticed more so since it's been cold that the fuel economy gauge drops right to 12 upon accelerating from a stop, regardless of how hard I actually accelerate. It stays at 12 until I reach the posted limit and doesn't go back up until I'm merely maintaining my speed. I was getting 21-22MPG city around Florida, so I'd like to think the cooler climate is taking its toll on my wallet.

What do you guys think? Should I flush my oil and opt for a more suitable lower-viscosity mix?

[galahad05]

That's the nature of these beasts.

My 335 gets ~28 mpg @ 75-80 mph on my highway commute. It gets 6-12 mpg during acceleration up to that speed.

[MikeS '06 330i]

Since your engine runs at the same temp regardless of Florida or WV, oil grade is irrellevant. The biggest difference is viscosity at cold start, but unless your moving from Florida to Alaska, dont change anything.

[ShadyShifty]

Originally Posted by MikeS '06 330i

Since your engine runs at the same temp regardless of Florida or WV, oil grade is irrellevant. The biggest difference is viscosity at cold start, but unless your moving from Florida to Alaska, dont change anything.

I read this thread before posting:

http://www.e90post.com/forums/showth...l+fuel+economy

And I definitely get what you're saying, but living downtown means that my trips are usually <5 miles, and usually involve cold start ups. Would it be beneficial in this case to change the oil? I realize of course that synthetic oil isn't cheap, and I probably won't recoup the costs in MPG gains, but if it helps the longevity of my engine, it'll be worth it to me.

[VTECaddict]

You're fine unless you are living in REALLY REALLY sub-zero kind of weather.

[balgopi]

Im new to this too. I received my 07 e90 this past June 10. So this is the first winter I have faced in the northwest. Everytime I accelerate I am getting 12mpg or below. This didnt happen in the summer/fall. So, I am ASSUMING because it is cold?

[rothwem]

Your car will get worse MPGs in the cold than in warm weather because the engine will fast-idle and/or run rich to warm up the car quicker. Different gas grades and additives are also used in the winter that will lower your MPGs. Also, florida is dead-flat, while all of the parts of WV I've been to have been way hilly. Lastly, if all of your trips are <5 miles, 15-16 mpg really is not that out of the realm of possibility.

I don't think the oil has anything to do with it, honestly.

[carve]

You car takes longer to warm up when it's cold out. Before it warms up, it gets crap mileage. Marginally more pumping losses in the colder, denser air, too.

[Tom K.]

Originally Posted by carve

You car takes longer to warm up when it's cold out. Before it warms up, it gets crap mileage. Marginally more pumping losses in the colder, denser air, too.

+1. 5w30 BMW synthetic oil is fine for your car, whether in FL or WV. Or did your dealer in FL put in something like 20w50? (If so, I'd change it immediately as in addition to being the wrong viscosity, it wouldn't be BMW approved oil.)

Tom

[RFGuy_KCCO]

Does WV use oxygenated gasoline blends during the winter months? If so, that could very well be the difference, as oxygenated gasoline has been reported by others to reduce MPG's in the past.

Your oil is not the issue, that I can assure you. I'm sure the BMW dealer used the standard BMW 5W-30 oil, which is fine in the WV climate.

[Traveling1]

Florida is a fairly flat state, where West Virgina isn't. That alone should hurt your mpg.

[roundle]

Since you are now in a cooler climate, check your tire air pressure. I bumped mine up to the factory 100MPH+ PSI and have realised about a 10% increase.

As for temp, cars do run a bit rich while they are warming up. And yes, my car's Avg MPG goes down-hill if I spend too much time in stop-and-go traffic. I've filled my car up (while already up to temp) and done 450+ miles motorway, getting over 30 MPG. However, if I drive my normal mix of city (15%) and highway (85%) I cannot seem to average more than 25.

[flea333]

I was about to post the same issue. I just bought a used 328i and noted highway driving at 80mph was 25.5mpg - that made sense given the rating was 18-28.

Now that I started driving to work 3 miles away on back roads I get 15mpg!!!! WTF?

My instantaneous MPG shows a minimum limit of 6mpg when accelerating - not sure if it really is giving it all the gas considering I can press the pedal down more.

I got a 2011 335i convertible rental today while my car is in the shop and noticed the instantaneous gas usage while accelerating seemed much better. The average mpg on the computer when I got it was also at 20mpg which is what I was expecting from my car.

I asked the dealer to look into it.

[tony176000]

Originally Posted by galahad05

That's the nature of these beasts.

Well said. These cars beg to go faster, so fuel economy is tough to control, along with the colder weather. But just try all the normal fuel-saving tips AND drive like a granny--you'll see improvement!
I think the fuel economy meters are distractions and not all that informative (I could be wrong...).

[ENINTY]

A few points. The dealer should have used BMW's 5W-30 weight oil in your car in Florida. 5W-30 is the recommended oil for your car regardless of its location. I think you have a few issues:
1) your car is running a bit richer in WV due to colder weather.
2) your car is using a different blend of oxygenated gasoline for WV
3) your car is operating in a higher altitude in WV. Florida is mostly 80 feet above sea level, WV in Huntington is probably 1,000 feet above sea level.

All of these will affect fuel mileage. Also you took a brief look at fuel mileage while in Florida and now in West (By God) Virginia. To really evaluate fuel mileage trends you need to track fuel consumption over many tanks of fuel.

Enjoy your Bimmer in the mountains of West Virginia. Many people drive to WV just to drive on the awesome WV roads; you already live there.

[hipnotic]

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