[TwistedX]

Just got a CPO M235i 8AT Convertible with 28k on the clock and I've averaging 16ish according to the car for 80/20 (city/hwy) driving. With the exception of occasional spirited acceleration I've kept it in comfort or sport(chassis only) and hardly ever go above 3k before it shifts. Haven't even had the car a week yet and already had to top it off.

Am I crazy or what cuz this thing is getting the same mpg as my 5000 pound X6 xDrive35i!!!!

What can I do or look at for helping city mpg? What do yall run for tire psi?

[aerobod]

I normally run 35PSI all around on our M240i with M6. In terms of driving around the city, I find the torque is sufficient to be in higher gears a lot of the time. Typically 11 litres / 100km for 100% city (21 US mpg). Today I just drove 600km of which about a third of the distance was non-divided highway that required about a dozen full-throttle passing manoeuvres in 3rd gear, consumption for the tank of fuel was 7.6 litres / 100km (31 US mpg). I do find the B58 engine in the M240i though, is about 20% more efficient in fuel consumption than the N54 engine in our old 135i, I expect the N55 in the M235i would be somewhere in between them.

[Luftwaffe1O1]

I mean i drive like i stole it most of the time and average almost 19... so hmmm that seems a bit low.

[Snade]

I've been averaging 17 to 18 mpg on my 2015 M235i with MT. I'm about 90 percent city driving, 10 percent highway on the flat, straight roads of south Florida.

Cheers,

Snade

[morphomeman]

I drive mostly suburban two-lane roads, usually fairly short trips, and have averaged almost 20 mpg over the life of the car (30K miles), so yes that does seem low. Do you have an independent mechanic who can check out the vehicle? How long have you had the car? You can't trust mpg readings over short intervals.

[capt_and]

Have you reset the counter (hold the button on the left stalk until mpg resets)? A lot of the time, dealers will keep the car running and the MPG plummets - it will take time to get it back up without resetting the count.

My driving is mostly highway and I average about 26mpg. Maybe 28mpg if purely on highways. On track I am at 6.9 mpg.

[overcoil]

Originally Posted by capt_and

Have you reset the counter (hold the button on the left stalk until mpg resets)? A lot of the time, dealers will keep the car running and the MPG plummets - it will take time to get it back up without resetting the count.

My driving is mostly highway and I average about 26mpg. Maybe 28mpg if purely on highways. On track I am at 6.9 mpg.

Above post is correct - ideling will plummet mpg averages plus you’ve only had car for a week.

I idle for about five minutes on each of my start ups and it kills my mpg. I’m usually in the 19-21 mpg range. If I use the eco-mode ( w start/stop deactivated ) and watch real-time fuel consumption particularly outside of urban areas my fuel consumption goes up to mid twenties and even higher.

Though if I’m doing errands and playing around in Sport mode and driving fast I’ll go through a tank in 2 days.

[Shovelman]

For reference, my 230 goes 23 city, 37 highway (at 75mph) but my city driving is not too bad.

[p912guy]

In following the forums for a few years it appears some m235's do well with mpg and some don't. My daily commute is 13 miles each way so I have plenty of time for the engine to come to full temperature and my drive is a mix of expressway, 45 mph city streets with well space lights and urban stop and go traffic. I have the 6 MT and generally run between 2-3K rpm with occasional bursts to 4-5K rpm (because it's fun) while accelerating from a stop. All that said, my real world (actual measured miles/gallons used) is 21-23 mpg. With straight interstate cruising I will get 27-30 mpg depending on weather, traffic and terrain.

Remember too the fuel tank on the 2 series is tiny. I think the tank on my MINI Cooper S was bigger. I generally need to fuel up every 250 miles.

[aaaaah]

I was getting 23mpg during winter with snow tyres on for a 60/40 highway/city split.

Just started out on summer tyres again but can't get you a real improvement because I've been enjoying having traction again

[TwistedX]

The tire psi is 38F/46R, some of my trips shorter runs (5miles) and when I put the first tank of gas in i did clear the average mpg.

What can i do to improve it? I bought the car as a CPO so I'm not sure what they could of missed, I'll run a can of seafoam through the gas tank to see if that helps

[overcoil]

Originally Posted by TwistedX

The tire psi is 38F/46R, some of my trips shorter runs (5miles) and when I put the first tank of gas in i did clear the average mpg.

What can i do to improve it? I bought the car as a CPO so I'm not sure what they could of missed, I'll run a can of seafoam through the gas tank to see if that helps

Don’t use seafoam

[p912guy]

Originally Posted by TwistedX

The tire psi is 38F/46R, some of my trips shorter runs (5miles) and when I put the first tank of gas in i did clear the average mpg.

What can i do to improve it? I bought the car as a CPO so I'm not sure what they could of missed, I'll run a can of seafoam through the gas tank to see if that helps

As far as I know, the only thing you can do is ease up on the go pedal a bit. Also, you don't mention what octane you are using. If you are using a mid-grade (90-91) vs high-grade gas, you're mileage may not be as good since timing may be retarded to prevent premature detonation. While we all would like good gas mileage, if you're running the N55 or B58, vs the N20 or B48 you've already made a decision that gas mileage is a secondary concern. I knew exactly what I was giving up and what i was getting when I switched from my MINI Cooper S which would get 38 mpg on the interstate to my BMW m235i.

[TwistedX]

Originally Posted by p912guy

As far as I know, the only thing you can do is ease up on the go pedal a bit. Also, you don't mention what octane you are using. If you are using a mid-grade (90-91) vs high-grade gas, you're mileage may not be as good since timing may be retarded to prevent premature detonation. While we all would like good gas mileage, if you're running the N55 or B58, vs the N20 or B48 you've already made a decision that gas mileage is a secondary concern. I knew exactly what I was giving up and what i was getting when I switched from my MINI Cooper S which would get 38 mpg on the interstate to my BMW m235i.

I've used seafoam in the gas tank before with no issues but I wouldn't use it anywhere else, but it would be a last effort after a month or so of driving to get the real world mileage.

I came from a 4cyl C300 so I knew it would be less but to get nearly the same at my 2016 BMW X6 with the n55 when it weighs 1/3 less is the concerning part. I do go easy on the pedal 85% of the time and I fill up with 91 because that's the highest in CA.

[Maynard]

Check alignment - easy to get it knocked off settings, common to have this neglected if CPO processing was rushed, and it can really eat into mpg. Also, use the short-term mpg ratings from the info screen (the one that can reset for each trip), not the long-term lifetime cumulative #. And I'd recc using Techron if you have to run cleaning goo (with a tank of no-ethanol, if you can find it) - DK what 'seafoam' is but it sounds a bit scary.

[Lucky13]

Something is definitely wrong with your car. I am retired and do 100% city (all 1-5 mile trips with no warm up) with a lot of stop lights and posted speed limits of 30-45. Manual transmission and always sport or sport+ and ave of 19-20 mpg with 93 octane. I do not baby it but take it easy the first few minutes. On the rare occassion of interstate driving its more 26-27 for the interstate of 10-15 miles.

[cxp213]

I drive nearly 100% city and average 19.x mpg in my M235i.

My two 440i loaners over course of 6 months averaged 22 mpg on the same commute.

Originally Posted by ScottSinger

Don’t use seafoam

Why not?

[overcoil]

Originally Posted by cxp213

I drive nearly 100% city and average 19.x mpg in my M235i.

My two 440i loaners over course of 6 months averaged 22 mpg on the same commute.


Why not?

I expect to be kicked off this forum for linking to a Scotty Kilmer video but choosing or even needing a fuel cleaner on direct injection is not easy or shown to help. High quality fuel is the key and additives can bind with water or alcohol in the tank and in certain situations take a toll on fuel pump.

[pz619]

14 MPG average and got the car new. Granted I'm always on city streets but for me the gas mileage is atrocious. I've dipped into single digits many times as well.

[Shovelman]

pz there is definitely something wrong there.

[TwistedX]

Originally Posted by Maynard

Check alignment - easy to get it knocked off settings, common to have this neglected if CPO processing was rushed, and it can really eat into mpg. Also, use the short-term mpg ratings from the info screen (the one that can reset for each trip), not the long-term lifetime cumulative #. And I'd recc using Techron if you have to run cleaning goo (with a tank of no-ethanol, if you can find it) - DK what 'seafoam' is but it sounds a bit scary.

I'll take it in and ask them to check it, got an issue with the HVAC controls where the passenger side air direction doesnt go any higher than 2 bars where as the driver does. I'll see if they can check the alignment and raise my headlights too

[overcoil]

Originally Posted by TwistedX

I'll take it in and ask them to check it, got an issue with the HVAC controls where the passenger side air direction doesnt go any higher than 2 bars where as the driver does. I'll see if they can check the alignment and raise my headlights too

Are u describing the air flow led’s on the seat icon ?
That’s the way it should work.