[futureal33]

Morning all

I posted recently about comparing my recently acquired 340i against my previous m235i - in particular, the MPG.

I have just contacted the dealer that I bought the car from about it, and they have just arranged to come and collect my car to investigate it.
The dealer is traveling over 100 miles to come and take the car off me, so I assume they are taking my complaint/question seriously.

I just thought I would post here to see if anyone else has any input or advise as to what could be the issue - or any suggestions what to do?

Data as follows:

M235i - over 15,000 miles / 1.5yrs - average MPG sat at 34mpg

340i - currently sitting at 22mpg doing the same commute, and with less aggressive driving.

The 340i has done 9000 miles from new. The 235i had done 25,000 when I returned it.

I know the 340i is heavier (touring also) but I can't see how this could result in over 10mpg difference - also given than the newer *40i engines are meant to be more efficient?

Thanks for any help on this

**I should probably add... I didn't buy this car expecting great MPG. I would have got a 320D if that was the case! I'm just disappointed with how much worse it seems to have got, versus the previous N55 engine!**

[Cuninho]

I've never managed to get my head around the MPG on these cars.

I'm in a 435i and average 19MPG haha, so you're beating me at present.

Suprisingly good MPG for a 235i though that isnt it?

[AlanYoro35i]

Originally Posted by Cuninho

I've never managed to get my head around the MPG on these cars.

I'm in a 435i and average 19MPG haha, so you're beating me at present.

Suprisingly good MPG for a 235i though that isnt it?

when i had my 435i i avergae 25mpg 70% MW, when i had n54 335i my av was 23.4.

[Rukka]

I am surprised at that because my experience was the exact opposite.

I had an M235i and on "my" commute/usage pattern, I saw 22/24 mpg. Now, with the 440i I see about 28 for the same pattern (see Fuelly sig below).

I did notice though, that over winter, the 440i mpg dropped by about 3mpg from the typical norm. Now it's warming up again, the average is creeping up.

I'd be interested what the dealer says or finds on yours though.

[Cuninho]

Originally Posted by AlanYoro35i

when i had my 435i i avergae 25mpg 70% MW, when i had n54 335i my av was 23.4.

Nice! I do about 30% MW which might explain it. If I do my routes in ECO PRO its like 24 MPG, but I prefer smiles per gallon unfortunately for me!

[NISFAN]

futureal33

Are you taking the figures from OBC, or with mileage/ refuel data. There could be quite a difference in accuracy if relying on OBC.

[DaveA]

Originally Posted by futureal33

Data as follows:

M235i - over 15,000 miles / 1.5yrs - average MPG sat at 34mpg

340i - currently sitting at 22mpg doing the same commute, and with less aggressive driving.

Must admit that my figures are significantly better than that (see figures in sig below), but I have noticed that you can drop the averages significantly around town and in urban areas... On a relaxed motorway run, I sometimes get 40/41 averages (the 50 mph roadworks help)...

I certainly would not expect such a big difference between the 235 and the 340... Certainly for similar driving and routes... I didn't get such a big drop going from 330d to 340i, where you might expect it...

[JD6]

It does sound an odd difference between the economy of those two cars. I wonder what the dealer will make of your lack of catalytic converter. It seems unlikely to be due to that, but a lazy dealer could use it as an excuse...

[Chrismac13]

I am getting around 28-30 mpg out of 35i at the moment. Which is alot better than i was expecting

[Steven1077]

I got 22mpg from my M235i and 25mpg from my 340i on the same run

[futureal33]

Originally Posted by JD6

It does sound an odd difference between the economy of those two cars. I wonder what the dealer will make of your lack of catalytic converter. It seems unlikely to be due to that, but a lazy dealer could use it as an excuse...

That's back on for now! Although it hasnt made the MPG any different!

[JD6]

Originally Posted by futureal33

That's back on for now! Although it hasnt made the MPG any different!

Good idea. You don't want to give them an easy excuse.

[futureal33]

Originally Posted by DaveA

Must admit that my figures are significantly better than that (see figures in sig below), but I have noticed that you can drop the averages significantly around town and in urban areas... On a relaxed motorway run, I sometimes get 40/41 averages (the 50 mph roadworks help)...

I certainly would not expect such a big difference between the 235 and the 340... Certainly for similar driving and routes... I didn't get such a big drop going from 330d to 340i, where you might expect it...

See this is the sort of post that makes me wonder if something isnt right with it!
On the motorway, driving from Preston to Wigan - which is about 20 miles, I sat at 72mph.

I used cruise control the whole way.

Car was not loaded with anything, just me (driver) and no luggage. For this 20 mile stretch of motorway, I reset the OBC and looked at the MPG constantly. When I left the motorway it was on 28.

So @ 72mph for 20 miles... on cruise control the whole distance, the best it could manage was 28mpg.... does this sound right?!

[wlightning]

Originally Posted by futureal33

See this is the sort of post that makes me wonder if something isnt right with it!
On the motorway, driving from Preston to Wigan - which is about 20 miles, I sat at 72mph.

I used cruise control the whole way.

Car was not loaded with anything, just me (driver) and no luggage. For this 20 mile stretch of motorway, I reset the OBC and looked at the MPG constantly. When I left the motorway it was on 28.

So @ 72mph for 20 miles... on cruise control the whole distance, the best it could manage was 28mpg.... does this sound right?!

Does seem a bit low. Standard car? Have you owned it from new? If so how was it run in?

I've done 1500 miles in my F30 340i so far and I've gently run the engine in, no more than 4500 rpm in the first 1200 miles, with the occasional boot just to vary the engine load and speed. On motorways I get between 35-45mpg without trying. The other day I did 78 miles, ave speed 58 mph, 44 mpg. Return journey was same distance, ave speed 63 mph, 41mpg. My record is a whopping 47.6mpg from Manchester to Warrington. Each time car with 2 adults, 2 children and boot with bags.

Urban driving it's much lower, lower to mid 20s.

[futureal33]

Car was standard at the time yes.

Its an ex-demo, with 9000 miles on it. No idea how it was run in.
I've never seen figures anywhere mid 30's in this car, nevermind 40s!
235i used to do 40's on a good run (Alton Towers last year, 2 adults, 2 kids, boot full - averaged 41 for the entire door to door journey!)
I can't even get to 30 in this car!

[NotGotABimmer23]

34mpg seems ambitious for the old car. Have you noticed you are using 1.5x as much fuel? I question the mpg of the prior motor.

I have an m140i and get 24mpg average, would surprise me to see a bit less in the 3er touring.

[Rukka]

Yours doesn't sound right mate. When I go down to see my folks, which is only a 50 mile run (45 motorway) I can see high 30's to 40 just by going with the flow between 70-80mph and thats without trying. Drop to 60 mph and it's well up into the 40's as others have found.

Bit left field but - what are your tyre pressures like? Mine were at 2.3bar and I noticed my mpg had dropped off. Put them back up to 2.6bar and instantly gained on the mpg......

[HighlandPete]

Originally Posted by futureal33

See this is the sort of post that makes me wonder if something isnt right with it!
On the motorway, driving from Preston to Wigan - which is about 20 miles, I sat at 72mph.

I used cruise control the whole way.

Car was not loaded with anything, just me (driver) and no luggage. For this 20 mile stretch of motorway, I reset the OBC and looked at the MPG constantly. When I left the motorway it was on 28.

So @ 72mph for 20 miles... on cruise control the whole distance, the best it could manage was 28mpg.... does this sound right?!

If you have proven the accuracy of the OBC figures, and the readout is pretty accurate, then no, the 28mpg figure is not good. (My F11 535i will give better returns at 72mph than you are recording).

Are both cars mpg figures 'brimmed' figures, for your long term averages?

[Mustard3]

Your M235i figures do seem exceptionally good.

Mine:
Lots of short urban driving - around 22mpg
Longish motorway trip - around 35mpg

340i:
Lots of short urban driving - around 25mpg
Longish motorway trip - around 39mpg

[DaveA]

Originally Posted by futureal33

See this is the sort of post that makes me wonder if something isnt right with it!
On the motorway, driving from Preston to Wigan - which is about 20 miles, I sat at 72mph.

I used cruise control the whole way.

Car was not loaded with anything, just me (driver) and no luggage. For this 20 mile stretch of motorway, I reset the OBC and looked at the MPG constantly. When I left the motorway it was on 28.

So @ 72mph for 20 miles... on cruise control the whole distance, the best it could manage was 28mpg.... does this sound right?!

No, it doesn't... That's a fairly flat stretch of Motorway for much of it, isn't it... Well, a few ups and downs, but nothing major...

Are you using sports mode on both the stick and the switch...? They both run the car at higher RPM, which will give lower MPG...

[creepy coupe]

I can vouch for the M235i. I had mine for 14k miles and it returned 34 MPG

[Jack_is_Back]

Your figures for the 340i do seem low. My lifetime averages for comparison:

M135i - 27mpg

330d - 36mpg

340i - 26mpg

For context, I did a 100 mile round trip today down the M1/M42. Far from ideal circumstances, a lot of crawling traffic on the way down, few spurts on the way back - average was 35mpg.

Hope they find something.