How thirsty is the 3.5L i6 (5 speed)? How about the 4.0L v8 (wagon, auto)?
I can't answer directly for either, and it depends on the vehicle but I assume you're looking at 5-series cars. Try epa.gov for official statistics. Keep in mind either motor wants premium gas.
My old 3.2 733 consistently delivers 25-26 highway and 19-22 city. That's with over 250k on it, with a 4speed automatic and lock up converter.
The M30/5-speed in my old 533i could manage about 28 on the highway if I was reasonable. 22-24 was more common for mixed use. For comparison purposes, the M54/5-speed in my current 525i gets 30 in pure highway driving, and maybe 25-26 in mixed driving.
I don't have experience with the V8s, but their city performance is reputed to be mid-teens, while some claim high 20s on the highway.
The M5 averages 18 mpg around town. Haven't had it on a good highway run yet. I'd expect the 540 to be a little less thirsty.
My big fat 750Li with the 4.8 motor averages 19 mixed and I typically see 23 or so on the highway with my summer tires. Everything goes up 1-2MPG with the snows on.
If you mean the big six they used in 5, 6 and 7 series cars up until the early 90s, the guys who have already posted about it are correct - on the highway you should get better than 25mpg, depending on the rear axle ratio (I've done nearly 29, but that was driving across the flat expanse of Iowa at posted speeds.)
Autolex wrote: my 325Ti is getting around 23-26Mpg mixed (60-70% highway).
i din't know if I'd consider that a "Big BMW"
Keith wrote: The M5 averages 18 mpg around town. Haven't had it on a good highway run yet. I'd expect the 540 to be a little less thirsty.
You speak like you have an M5....is this true?
v8 BMW wagon 14 city 20 highway when using Sport mode often
No sport mode 16 city 21 highway
This is based on the in-car computer not EPA reports
My friend has a 1998 540i 5speed auto and with mostly highway driving he averages between 21-22 (says the dashboard reading). Any stop and go driving and you are lucky to see 18. That engine is thirsty! It does make a nice sound (after opening up the exhaust), and makes a damn fast saloon.
I've heard of well maintained (no vacuum leaks, fresh O2 sensors) 540i's getting 27mpg on the highway at reasonable speed.
It's a heavy, powerful car..and city mileage is pretty much indicative of that+driving style.
Nathan
my E39 530 (3.0L I6) Auto gets me 27-30 mpg on the hwy. All depends on how fast I go and what wind is around. The has 100k on it now. This actual as my in car computer reas 1-2 mph higher than that.
City mileage is around 24 mpg.
My mom's 1997 740i get's around 22-24 mpg on the highway (if she's driving) and about 0.8 mpg if I am driving...
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