Average MPG on your 135?

[shodanusmc]

Over all average is around 21....mix of city and highway.

[JHZR2]

Originally Posted by maxnix

Never have understood why the 6MT are rated higher than the 7 speed DCT. I think the final drive ratios are pretty close.

The MT is 0.87 avainst a 3.08 final and the DCT is 0.69 against 3.42. That would stick the MT with a final ratio of 2.67 in top gear versus 2.35 for the DCT. The DCT should spin slower and Id think get better MPG. Maybe not, maybe at normal highway speeds it is too slow to take advantage???

Or perhaps the added weight and shift logic causes less efficient operation (holding the gears too long or something)?

Sure seems odd for the DCT to be 25 when the 6MT is 28. I'd expect the DCT to be 29 or 30, with gear 6 and below having similar ratios to the MT... Thought IIRC the DCT first gear is more aggressive.

[qcodec]

25.7, 13,000 miles, stock, 80% Highway...(2008 auto)

average speed 43.5

[michifan]

Originally Posted by maxnix

Man, I got a 4.5L V8 in a 4100 lb. car with a 4 speed automatic that will do that.

22-23 MPH @ 80. I've done better at lower speeds, and maybe the heat has something to do with it.

I came from an Infiniti M35x, and the 135i gets 3mpg better on the same commute.

[JHZR2]

Originally Posted by maxnix

Interesting numbers. According to my 2011 1 Series Coupe brochure, 6MT top gear is .85 while the drive is 3.08, so 2.618, or ~2.62. DCT top gear is 1 and final is 2.56, so 2.56. Only 2% difference, so insignificant.

First gear though is a little more different.

6MT 4.11 x 3.08 = 12.6588

DCT 4.78 x 2.56 = 12.2368

So better launch for the 6MT.

Better numbers than what I pulled from the internet then...

There is no OD on the DCT though???!? I find that hard to believe... there is enough torque that with 7 gears, Id have thought they would put an OD on there and let 6 and below match with the MT.

2% is small, but it is a difference in mechanical advantage that should yield fuel economy. Wonder why the DCT is such a drop...

[BahamaBart]

Originally Posted by michifan

When I run highway @ 80mph (cruise and sixth gear) I get about 22.

Around town 17

Ditto

[Temming]

25.2 mpg average with 70% highway driving. Best on a long trip was 29 mpg.

[MassiveMP2]

I'm getting around 16-17mpg mixed driving!

[RPM90]

Originally Posted by radiantm3

I get an average of around 16-17. I say if you aren't getting under 20, you probably aren't enjoying the car enough.

Nah.
It depends on a number of factors.
Stop and go city, long highway commute, hilly terrain, country roads, etc...
Tire pressures, tire type, weather conditions, passengers, AC on/off, etc...
All those lead to various MPG as we see listed here.

How you drive is probably at the top of the list though, but many other factors contribute quite a bit.

I enjoy my 135i plenty. Also, I have a 17 mile each way commute to work, where 10 of those miles is high speed highway.
The rest of my driving is high speed country roads, where there are long stretches of road punctuated by stops signs. It's fairly flat around here too, but there are some hills out here as well.

Seems almost no one is listing their trans. I think it matters, and it helps to know to see if there is a particular pattern.
My 135i is a manual, and I run 42psi rear and 39frt.
Tires are Conti all season non RFT.
With AC on I get about 21MPG avg.
With AC off I get 22-23mpg avg.

Lately, it's been very warm, but more so, VERY humid. I'm running my AC daily and for the duration of my trips.
My power feels about the same as when BMW redid the programming in spring, which is to say...lacking, compared to how it was before.

[RPM90]

Originally Posted by schmeah

Ok, here's a stupid question, but when BMW quotes avg MPG for a 135i DCT, is that it auto/manual/sport mode or what? There must be a difference, because sport mode and M mode run cosistently run higher RPMs than in auto mode. It would be misleading if they quoted the max MPG based on auto operation when almost no one drives a DCT in auto mode.

I'll bet it's based on the standard "auto" mode as that is the default for the trans. The other programs are optional and it's drivers choice.

I don't think it's misleading at all. Take a true manual for instance, they base the MPG on "normal" driving. But, there is a lot of variation on how drivers will drive a manual. Some will short shift, some go near red line for low gear shifts, some skip shift, etc...
A car maker can't account for all drivers, so the test simply gives an average, and if you look closer at the EPA ratings, there is a "range" of mpg's as well. They can fluctuate quite a bit.

[RPM90]

Originally Posted by JHZR2

The MT is 0.87 avainst a 3.08 final and the DCT is 0.69 against 3.42. That would stick the MT with a final ratio of 2.67 in top gear versus 2.35 for the DCT. The DCT should spin slower and Id think get better MPG. Maybe not, maybe at normal highway speeds it is too slow to take advantage???

Or perhaps the added weight and shift logic causes less efficient operation (holding the gears too long or something)?

Sure seems odd for the DCT to be 25 when the 6MT is 28. I'd expect the DCT to be 29 or 30, with gear 6 and below having similar ratios to the MT... Thought IIRC the DCT first gear is more aggressive.

On BMW's website the mileage ratings are still listed as "TBD".

I think you're citing the final drive from the step automatic.
The DCT runs a rather tall 2.56 final drive, the manual is as before with a 3.08.
But, the primary gears in the DCT are quite a bit shorter than in the manual. The primaries need to be short due to the tallish final drive.
Another MPG factor is that the DCT doesn't even have an "over drive" gear. 7th is a 1:1 ratio.
The manual is 1:1 in 5th, and has a .85 6th over drive gear.

Yeah, it's odd why BMW choose this setup. There are 7 gears and no over drive to take advantage of that many gears.

The manual has a slight quicker, shorter, 1st, when combining 1st with final drive.
Top MPH in 1st is less for the manual as the overall ratio is shorter.
But, in 2nd and above, the DCT gets the short gear award. The gears are tightly spaced, much like a race trans.

[TJ bmw135i]

These are the averages the car calculates. I reset the logging then have checked after a full tank of 93 fuel. I have the 135i 6MT. typically I get 27.5 on long highway trips. I will get 24 on mixed city and highway (as long as I keep my foot out of it) and 19.4 on city only. My avg highway speed for a full 300 miles was 74.2 including one quick stop.