[HX_Guy]

Did a very normal all surface roads drive to the gym and back this morning, 19 miles round trip, 41.1 MPH average speed, 20.9 MPH in Comfort mode with regular/semi-spirited driving. Floored it once or twice and drove ~55 MPH and caught a few lights.

[3.0L]

Originally Posted by mczoomer

Following this thread with interest. It sounds like on average the M235i fuel economy is slightly below that of the 335i, which makes sense given the slightly greater HP, and very similar weight. I believe the fuel tank on the 335i is 2 gallons more -- so on one tank, the range of the 335i is considerably greater. Does this sound roughly correct? I'm debating between the two cars.

I don't know what the real-world MPG is for a 335i. My new M235i has averaged 26+ combined MPG since the day I picked it up. Did a 360 mile trip a few weeks ago and got 34.7 MPG. Most of that trip was at 70 to 82 MPH on the interstate with bursts to 95+ to pass a string of semi trucks. Did the whole trip in Comfort Mode.

[ska///235i]

Originally Posted by 3.0L

I don't know what the real-world MPG is for a 335i. My new M235i has averaged 26+ combined MPG since the day I picked it up. Did a 360 mile trip a few weeks ago and got 34.7 MPG. Most of that trip was at 70 to 82 MPH on the interstate with bursts to 95+ to pass a string of semi trucks. Did the whole trip in Comfort Mode.

You need to reset the avg mpg setting or you will keep getting these high mpg figures cuz the system is still averaging that long eco pro trip that you did....unless you do these long trips all the time

[HX_Guy]

Can you set the trip computer to auto reset every day, but the long term one has to be reset manually.

[turnstile]

So using the Comfort setting 90% of the time I got 14mpg average this tank. Thats non-spirted driving, all city. Average speed was 12.3mph. Going to take the car into the dealer as I find it hard to believe the EPA estimates are off by almost 33%.

1st tank - 13.7mpg - Total miles - 178
2nd tank - 14mpg - Total miles - 184

[HX_Guy]

Dude, average speed of 12.3 MPH?

That's the problem right there and your MPG is probably what it should be. You're barely moving along, either A LOT of stop and go driving, or you idle A LOT or you do a lot of super short trips/lots of driving through parking lots.

I just got done with another tank of gas an my average was 19.5 MPG and the average speed was like 36 MPH.

[turnstile]

Originally Posted by HX_Guy

Dude, average speed of 12.3 MPH?

That's the problem right there and your MPG is probably what it should be. You're barely moving along, either A LOT of stop and go driving, or you idle A LOT or you do a lot of super short trips/lots of driving through parking lots.

I just got done with another tank of gas an my average was 19.5 MPG and the average speed was like 36 MPH.

I drive in Los Angeles, 8 miles each way to and from work. Its all surface streets, and all stop and go. Still, how can my average be so far off of the EPA estimate of 22mpg.

My previous M3 had an EPA city estimate of 14mpg, I got 12.5mpg driving the same exact commute.

[HX_Guy]

Same commute in your previous M3 as you're doing now?

BTW the EPA city test is done with an average speed of 20 MPH, so you're 12.X is much lower, almost half. The average speed, and the amount of stops you make, probably have the greatest influence on your MPG, much more than how fast you accelerate (if say you made less stops and accelerated faster vs more stops and accelerated slower). I notice a dramatic difference in my MPG if my average speed is say 33 MPH vs 43 MPH, like 3-4 MPG difference.

Here's actually a great example...just earlier today I went to fill up the tank and then stopped by Target on the way back home. After I filled up, I reset the onboard computer so I just went to check. Total trip after filling up was 1.9 miles, average speed was 12.6 MPH and I got 11.3 MPG!

[Vlad-Miami]

;-) 42.6 highway average lol

[mczoomer]

I haven't taken an average or tried to separate by reported fraction of city/highway driving, but studying the numbers posted here and on fuelly.com, I'm not really seeing a clear pattern supporting the EPA's rated 2 mpg advantage of the automatic over the 6MT.

It makes sense to me that in principle, with 8 gears and an efficient controller, the auto would be more fuel efficient, but I'm wondering if the real-world numbers bear that out...?

[RPM90]

Originally Posted by mczoomer

Following this thread with interest. It sounds like on average the M235i fuel economy is slightly below that of the 335i, which makes sense given the slightly greater HP, and very similar weight. I believe the fuel tank on the 335i is 2 gallons more -- so on one tank, the range of the 335i is considerably greater. Does this sound roughly correct? I'm debating between the two cars.

Range is greater in the 335i due to the larger tank.
The 335i has 300hp/300lb ft. The M235i 320hp/330lb ft.

The base weight of the 335i AT is 3595lbs.
The M235i AT is 3535lbs.
But that's the base 335i, with Msport I'm sure there are a few more pounds.
Still the M235i is one heavy small coupe.

The biggest difference in MPG in the 2 and 3/4 is the trans choice.
The 8sp AT has 2 over drive gears and that helps quite a bit in getting better average MPG.

My 335i Msport w/sport AT averages about 25mpg with about 40% city and 60% highway. More highway driving of course improves MPG.
M235i MT drivers are getting a good bit lower MPG. 1 because the MT has only 1 over drive gear, and 2 I'm thinking M235i drivers drive more aggressively.

Sport+ mode with AT in sport mode, shifter to the left, won't engage 7th until around 60-70mph. 8th gear is pretty much locked out.
For highway driving and best MPG it's best to put the trans in full auto mode or use manual mode so that you can engage 8th sooner.

There are a number of drive settings that can be configured in the 2, 3/4 and that makes for a range of different MPG.
Then, add drivers who drive differently and "average" MPG for these cars is all over the place.

If one drives in sport+ or sets sport mode to "chassis + drivetrain" the throttle is more aggressive, and that likely leads to more aggressive driving and throttle use lowering MPG.

I'm changing over to a M235i will likely go with the MT this time.
MPG will lower a bit, but I really want to get back into an MT.
BTW, "ECO" mode is useless from a performance car perspective.
I can't stand it. Everything a BMW should be is dialed back too much.
I tried using it for a bit and only got about 1mpg more, not worth it for how much it ruins over all performance.

[RPM90]

Originally Posted by HX_Guy

Oddly the automatics have the exact same gas mileage ratings but the manual 335i is rated better, not sure how that makes sense.

For once though, the EPA ratings are actually pretty spot on in my experience.

Part of the reason is that the 335i is the base model that uses non high performance and narrower tires. The M235i uses high performance tires in a staggered set up with wider rears.
A 335i with the staggered set up will likely lower average MPG a bit.

EPA testing is not done in a performance driving manner. It's driven at a moderate level so that not all of the engines power is called upon.
That's why the 328i and 335i AT's get nearly the same MPG.
In the real world of performance driving the 328i will get a bit better MPG vs the 335i, because the 2.0 turbo doesn't produce the power the 3.0 turbo can.
When you use more power you burn more gas.

On the 3 series forum MPG between a 328i and 335i is still pretty close as reported by owners. The 328i does about 2mpg better with comparable vehicle set up, and driven in similar fashion.

The biggest let down of the 2 series is it's weight.
3555lbs for the M235i AT, and 3345lbs for the 228i AT.

[RPM90]

Originally Posted by turnstile

I drive in Los Angeles, 8 miles each way to and from work. Its all surface streets, and all stop and go. Still, how can my average be so far off of the EPA estimate of 22mpg.

My previous M3 had an EPA city estimate of 14mpg, I got 12.5mpg driving the same exact commute.

As HX wrote, with low avg MPH you're doing a lot of city driving, that's the worst kind of driving for MPG.
Also, 8 miles each way means the engine isn't even getting fully warmed by the time you get to work and then back, so it's not running at it's peak efficiency while cold.

To get best city MPG you have to accelerate very slowly, but the problem is everyone's then on your ass to move quicker.
Lots of city drivers use the throttle like an on/off switch, jumping away from stops and lights to get going quicker.
That sucks gas when trying to accelerate a heavy car from a standstill, then repeat often.

[mczoomer]

Would all-season tires yield better/same/worse mpg compared to the summer/performance tires?

[ska///235i]

Originally Posted by mczoomer

Would all-season tires yield better/same/worse mpg compared to the summer/performance tires?

Better by a hair
Summer tires are stickier

[Boxman911]

I got this mpg driving in Eco/my car feels broken mode, drove at a steady 70mph on the motorway, this is probably the best I will ever get. It's an auto btw.

[HX_Guy]

Is UK MPG and US MPG rated different?

[mczoomer]

I guess UK miles are the same but gallons are bigger.

http://www.checkyourmath.com/convert...perial_mpg.php

From wiki answers: "The difference between the Imperial gallon and the smaller US Gallon might be explained by the fact that, in the post medieval past, the whiskey filled barrels leaving the shores of UK didn't have the same content when arriving in the new world...."

[Demetrius Joel]

Originally Posted by vivalaReagan

i drive almost exclusively in sport (wish i could figure out how to default to this mode & not have to select it every time, but i digress) and local city driving sans highways. i'm a bit of a lead-foot and have averaged 17.5 mpg over the first 800 miles.

ymmv (literally).

Same here, I average about 17-18. Ouch!

[3.0L]

Originally Posted by ska///235i

You need to reset the avg mpg setting or you will keep getting these high mpg figures cuz the system is still averaging that long eco pro trip that you did....unless you do these long trips all the time

Excuse me? The 26+ MPG average since day one is all driving combined. In other words, all city and highway driving. Everything. It is a very real number. I chose not to reset it. I do reset the second trip odometer at every refueling.

As to the 34.7 MPG I got on my last trip, I computed that mileage using the trip length (360 miles) and actual number of gallons I pumped in at the gas station. Those numbers do not lie.

[ska///235i]

Originally Posted by 3.0L

Excuse me? The 26+ MPG average since day one is all driving combined. In other words, all city and highway driving. Everything. It is a very real number. I chose not to reset it. I do reset the second trip odometer at every refueling.

As to the 34.7 MPG I got on my last trip, I computed that mileage using the trip length (360 miles) and actual number of gallons I pumped in at the gas station. Those numbers do not lie.

Was my comment offensive?

I was just trying to tell you that if you did a long trip and never reset your avg mpg then you will have higher avg numbers from your daily commute. So technically your numbers are not accurate since that 300+ eco mode trip was included in your calculation. Hope this doesnt offend you

[3.0L]

Originally Posted by ska///235i

Was my comment offensive?

I was just trying to tell you that if you did a long trip and never reset your avg mpg then you will have higher avg numbers from your daily commute. So technically your numbers are not accurate since that 300+ eco mode trip was included in your calculation. Hope this doesnt offend you

No, I'm not offended. Sorry if I came across that way.

As to MPG average... average is average. Right? I tried, in vain apparently, to show that my MPG from day one is combined MPG. Again, I achieved 34.7 MPG on my last trip, which was 360 miles. That figure was mixed into the combined MPG of the car since day one. Since day one, my car shows 26.1 MPG since new. How can you argue with the MPG average since new? It's a fact. When I say new, I mean the day I bought the car.

But sure, take short trips around town (which I do almost daily) and that specific trip will show much lower MPG. But please don't forget that those low MPG city trips are mixed in with the overall MPG since day one (in my case). And just importantly, all of my highway road trips (that generate higher MPG) are mixed in as well. COMBINED MPG is the significant word. It is not a lie. Pick and chose any trip segment you want but combined is real. So there it is whether you chose to believe it or not: 26.1 MPG average since new; the day I bought the car.