BMW M140i owners

Soldato
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I'm almost a year into 140i ownership, getting one from new on the 1st March.
They are a lot better on fuel than you might think, for a I6 350bhp engine! I've logged every mile I've done in the Road Trip app, really handy....

These figures are very close to what I get in my F10 530d. Admittedly, I am quite heavy footed and my normal commute includes a lot of start/stop traffic which ruins the fuel economy in a diesel. I've managed over 50 mpg on relaxed motorway journeys before.

Been very tempted to ditch my barge for one of these next year, but I'm currently leaning towards a more mature manual RWD preposition in the form of a miata. :)
 
Soldato
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They don't *have* to be, but on standard 95, you'll lose about 20bhp or so. The power and fuel consumption figures quoted are based on using the highest RON fuel the car is listed to run on.
Nonsense!

The N55 is tuned to run on regular 95 fuel. I took my M135i (with 800 miles on it) to an OcUK RR day a few years back and it pulled 349HP on bog standard supermarket 95.

What I WILL say though, is that after about 40k miles of only regular fuel I began to see a gradual decline in fuel efficiency. From that point I switched to only using Shell V-Power or BP Ultimate and over the course of about 4-5k miles the economy slowly came back to what I originally achieved. I put this down to the injectors becoming blocked on the regular fuel. Premium fuel never achieved BETTER efficiency, or to my bum dyno any more power, than regular, but I'm convinced on its engine cleaning benefits.

The best I ever achieved was 44MPG on a Leeds to Milton Keynes run (door to door, not only the motorway bit). That was in Eco Pro with CC on almost the whole way, and sticking to 70mph where possible.
M135i_mpg.JPG


The N55, and I believe to an even greater extent the B58, are exceptionally efficient engines especially considering their power and displacement.

Over the 3 years I owned the car (from new to ~72,000 miles) I averaged 34.1mpg!
 
Man of Honour
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17 Oct 2002
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159,596
I put 2000km on a rented 540i the other month and averaged about 33mpg across virtually all motorway driving. If you kept it to dead on 70 it would creep up to about 37-38. Around town it was sub 20.

The performance, however, was incredible.
 
Commissario
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Herts
I put 2000km on a rented 540i the other month and averaged about 33mpg across virtually all motorway driving. If you kept it to dead on 70 it would creep up to about 37-38. Around town it was sub 20.

The performance, however, was incredible.
Does the 540i have the B58 as well?
 

Baz

Baz

Soldato
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9 Dec 2002
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Peterborough
I bought two last year, for the misses and myself, she doesn't get good mpg as she canes it everywhere! :D

Got 40mpg on a 1,000 mile round trip to Amsterdam, on motorways in traffic expect mid 30's, around town, mid 20's easily

Also no point in higher octane fuels, they don't offer any more power, there isn't more calorific content, just a reduces engine knock in hot weather.

Oh and be careful in the damp, they are lively buggers, but great fun - proper sleeper car.
 
Soldato
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Also no point in higher octane fuels, they don't offer any more power, there isn't more calorific content, just a reduces engine knock in hot weather.
This is only partly true. If an engine is tuned for higher octane fuel it can generate more power because the higher octane allows the ECU to advance the ignition timing further without suffering knock.

However as I said above, my experience in the M135i was that the real benefit of the premium fuel was the engine/injector cleaning effect resulting in more efficient running.
 
Man of Honour
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This is only partly true. If an engine is tuned for higher octane fuel it can generate more power because the higher octane allows the ECU to advance the ignition timing further without suffering knock.

However as I said above, my experience in the M135i was that the real benefit of the premium fuel was the engine/injector cleaning effect resulting in more efficient running.


I haven't done any back to backs with an N55 or a B58, but on an S55 M3 on the same dyno on the same day there was a 40 horsepower difference between regular 95RON unleaded and Tesco Momentum
 
Associate
Joined
3 Sep 2008
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462
I've averaged about 28 mpg over 3 years with the Auto, costs around £60 a tank - not completely empty.
250-300 miles a tank, really depends on the type of driving / how heavy your foot is.
 
Soldato
Joined
14 Apr 2007
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3,388
I'm approaching 3 years with my auto M135i. I fill up with Sainsbury's Super Premium and it costs around £56-60 to brim the tank which averages around 250-300 miles at a push. It is possible to achieve over 40MPG on a long run, as mentioned many times above. I managed around 44 on a round trip from Manchester to London.

Pilot Super Sports front/rear. I was going to switch to PS4's (not PS4S as 18" doesn't exist) but unfortunately struggled to find any in stock for a reasonable price. Fantastic on dry/ever so slightly greasy roads, not so great in the wet (PS4 should eliminate this issue due to wider channels).

BMW Warranty costs £320/annum (excludes Emergency Service). Servicing relatively inexpensive, especially if you shop between dealers/groups or go down the route of a BMW specialist.

If you're seriously considering an M140i, you should drop TRL from BabyBMW a message. He works for Berry Heathrow BMW and is widely known for sorting the best M135i/M140i (some M2 also) deals. I'll be going down this route when I change to an M2C.

I can only comment on my M135i - but the acceleration/performance is staggering, especially when you consider that it can be relatively economical over longer drives while not costing the world to run.
 
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