Today I did a 3 car mileage comparison test. It was a 13 mile highway round trip averaging 60-65 MPH. The results are as follows:

X5 Diesel 33 MPG

535xi sedan 27 MPG

530xit 31 MPG

All results are using the BMW computer. Both the X5 and 535xi had less than 100 miles on the OD, my 530xit has 40000 miles. I'm thinking about replacing my 530 with either a 535xit or the X5 diesel. I would prefer to go with the 535xi, but I don't want to take such a substantial mileage hit. Any thoughts on my test and the results would be appreciated.

 

Travelling at 65ish miles per hour... It seems a little low for a 535xi. But then... I drive a Camry for my daily commute, and then have fun with the pedal to the metal whenever I can with my 535xi. It's not really advertised as an economiser!

 

13 miles may not be enough to average out any quick starts you may have done with the 535xi.



Come on. Admit it. Certainly you had to get on it at least once to feel the turbo.

PS: Is mileage your first/only concern? Even at that, its only 10% worse. What's your current monthly gas bill? Will 10% more break the bank? Or is it worth that cost for the extra power and fun?

 

I got on both the diesel and the 535xi before I reset the trip computer. Both are quick. At speed, the diesel feels and sounds very similar to a gas engine, but at idle there is a slight vibration and from outside the vehicle you can tell its a diesel.

I know in the big picture the additional cost in gas between 27 and 31 MPG isn't a deal breaker. I guess I was hoping someone would tell me that the 535xi can get better mileage and somehow my test wasn't accurate.

 

You would really want to compare a broken in 535xi to your car - not one with only 100 miles.
In addition, the extra cost on diesel for the X5 is going to make it more expensive that what you have now as well.
Finally, comparing the 535 to your 530, assuming you drove all highway miles for 12,000 miles a year, you have the following:
If gas is $4 a gallon, your extra cost will be $229 per year
If gas is $3 a gallon, your extra cost will be $172 per year
If gas is $2 a gallon, your extra cost will be $115 per year

Something tells me the extra power of the 535 is worth the incremental cost in gas

But like I said...no fair comparing a tight unbroken in engine with one that has 40K on it....

 

Richard's right --- the only valid mileage comparisons are going to be longer term - hundreds of miles. I don't think we buy these BMWs for economy first, anyway, as doug said, a couple hundred bucks per year difference?
Cal

 

Your overall fuel economy (with some balance of city and highway driving) won't come close to those numbers. For one, any all wheel drive vehicle will deliver lower fuel economy than a FWD/RWD.

And, come on now - buy the 535 sedan or touring you will get itching under your right toe and that turbo will suck enough gasoline to make both you AND the Arab oil producing nations smile.

As a point of reference, I've tracked every gallon of gasoline that has come in the tank and out the exhaust of my 530xi during the past 25K miles or so. I consider myself a conservative driver doing a mix of 35%city, 15% rural, 50% highway driving and my overall MPG is 22.98 (using premium fuel).

 

Why are you complaining about 27 mpg, sounds darn good to me for a near 4000 lb vehicle with a powerful engine.

 

Exactly, the sticker on the windows say what? 25 MPG average on the highway. I drive mostly highway and usually average between 22-25 MPG each tank in my 08 535xi. That's with enjoying the car. Why buy the car if you aren't going to use those turbos. If you are that worried about the costs and MPG then you should go buy a Prius.

 

Thanks for the good feedback.

Regarding some of the other comments...I don't want a Prius! And 27 MPG is not bad. My 530xit is the same vehicle as the 535xi but with 260 HP instead of 300 HP (but the 535xi has direct injection which is in theory more efficient). When I drive around town I would love to get on the turbos...and I wouldn't care about the mileage. On the other hand, I twice a year I do a round trip between Seattle and Phoenix. I've done about 7 of these trips in my 530xit and the computer always shows an average between 27-28 mpg. If I extrapolate my test comparison between my 530xit and the 535xi to my Phoenix Seattle round trip, the 535xi would average 22-23 mpg. In reality its a matter of how you feel about a car...you want the power, but you also want it to be efficient...is that too much to ask for a $65000 car?