M135i - Reckon i could get 30 mpg?
M135i - Reckon i could get 30 mpg?
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Discussion

CJ22

Original Poster:

43 posts

155 months

Tuesday 15th December 2020
quotequote all
I'm currently trying to decide what to get for my next daily driver. I've been in diesels for a while now, but with diesel ban zones and just generally missing petrols, i have an itch to go back. However, i do a fair amount of miles, so i'm going to need something that's reasonable on fuel.

So as in the title, can anyone who's owned one tell me if i could get 30mpg from a M135i whilst driving it sensibly? My commute consists mostly of straight forward, traffic free B roads and motorways, and it's always at a relaxed pace. I've been in coupes and saloons for nearly all my driving life, and i've never had a quick hatchback, so it's an itch i'm looking to scratch.

Edit: I'm referring to the older 6cyl M135i's in particular. Will likely end up being a pre-facelift aswell if that makes any odds.

Edited by CJ22 on Tuesday 15th December 01:03

Pebbles167

4,598 posts

182 months

Tuesday 15th December 2020
quotequote all
Not exactly the same I know, but my dad bought an M235i Gran Coupe earlier this year. Regularly gets 30mpg mixed driving. Nudges 40 on longer journeys, and plummets when driving hard.

Impressive really, for a 300bhp car.

Worth noting that this is the 4 cylinder turbo that the current M135i also has. If you're on about the older 6cyl turbos, itll likely be harder to achieve.

CJ22

Original Poster:

43 posts

155 months

Tuesday 15th December 2020
quotequote all
Ah, good point. I am referring to the older 6cyl M135i's. I know the older N52 (albeit a naturally aspirated 6 cylinder) that came in the E92 330i's was able to achieve 30mpg. I'm just wondering if although being turbocharged, with the engine in the M135i being a bit newer they may have been able to squeeze a bit more fuel efficiency out of it.

Driver101

14,451 posts

151 months

Tuesday 15th December 2020
quotequote all
It all depends on how you drive, but 30mpg is achievable. Some people are averaging over 30mpg long-term.

Edited by Driver101 on Tuesday 15th December 10:36

Court_S

14,754 posts

207 months

Tuesday 15th December 2020
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I have an M140i, so the later B58 and my long term average is 29.4mpg.

I’ve not reset the trip computer since I picked the car up last June. It was hovering just under 31mpg for a while but it’s dropped since I’m not commuting. On longer runs it’s pretty good on fuel but it drops quite quickly on short trips or if driven hard.

The auto box helps quite a bit with economy with the tall 8ty gear.

cannedheat

953 posts

305 months

Tuesday 15th December 2020
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My M135i xdrive has a long term average of 9.2l/100km, so around 30.7mpg and I’ve seen over 40mpg on long trips. I imagine the RWD version will do even better with its lower weight and driveline losses.

Sam.F

1,145 posts

230 months

Tuesday 15th December 2020
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Assuming you can rein yourself in on the single carriageways and your route isn't overly hilly, even in a pre-facelift M135i you'd easily average over 30mpg.

Use the performance more than occasionally and it will drop off significantly though.

As others have said the ZF8 box helps economy at a cruise significantly, though overall I have found over 3 M-lites (one manual and 2 auto) over the last almost 8 years it makes little difference to my overall average which sits at around 26mpg. I'd say on a gentle-ish motorway cruise the auto will easily crack 40mpg where the manual would be 2-3mpg less.

swanny71

3,588 posts

239 months

Tuesday 15th December 2020
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30mpg definitely achievable if you don’t spend all your time in town or driving it like you stole it.
I’m averaging exactly 31mpg (calculated) in a manual over 10k miles. Auto’s are supposed to be more economical.

CJ22

Original Poster:

43 posts

155 months

Tuesday 15th December 2020
quotequote all
Sounds promising so far!

It would be the auto i'd go for. My current car is an auto, and also the first automatic i've owned. I've found an auto to be a far more relaxing drive, and i'm happy to cruise along for the most part. In a more engaging manual, i'll soon get carried away and the mpg will plummet.

Edited by CJ22 on Tuesday 15th December 21:45

hiccy18

4,183 posts

97 months

Tuesday 15th December 2020
quotequote all
If you're smooth it's straight forward to top 30mpg in all bar stop start and urban driving, on a run I usually get mid to high 30's from a manual, on the daily urban slog high 20's.

Mr Tidy

31,627 posts

157 months

Tuesday 15th December 2020
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I've currently got my 4th manual N52 engined BMW and they have all easily averaged 30+mpg, but here is a link to a thread where a couple of M140i owners have also averaged over 30mpg so I would have thought an M135i should manage it too:- https://www.pistonheads.com/gassing/topic.asp?h=0&...

survivalist

6,124 posts

220 months

Wednesday 16th December 2020
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CJ22 said:
Sounds promising so far!

It would be the auto i'd go for. My current car is an auto, and also the first automatic i've owned. I've found an auto to be a far more relaxing drive, and i'm happy to cruise along for the most part. In a more engaging manual, i'll soon get carried away and the mpg will plummet.

Edited by CJ22 on Tuesday 15th December 21:45
I’ve got an N54 335i with the 6 speed ZF slush box and barely drive on the motorway these days. I get 26MPG so unless you’re treading your commute like the cannonball run I recon you’ll be fine.

DuckSauce

390 posts

97 months

Thursday 17th December 2020
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I go most places in eco mode with mine and its very easy to get 30mpg. The downside is the small fuel tank, I'm used to bigger tanks in previous cars.
I get anywhere between 300 and 350 miles to a tank, depends which route I take to work 😉

Court_S

14,754 posts

207 months

Thursday 17th December 2020
quotequote all
DuckSauce said:
I go most places in eco mode with mine and its very easy to get 30mpg. The downside is the small fuel tank, I'm used to bigger tanks in previous cars.
I get anywhere between 300 and 350 miles to a tank, depends which route I take to work ??
The small tank is a pain the in arse. At first I thought it was brill that it didn’t cost much to fill up....I soon realised that I was just spending more time at the fuel station.

Aftershox

397 posts

188 months

Thursday 17th December 2020
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Driver101 said:
It all depends on how you drive, but 30mpg is achievable. Some people are averaging over 30mpg long-term.

Edited by Driver101 on Tuesday 15th December 10:36
My 2015 M235I is long term average (13,000 miles) of 33.3 mpg.

Mr Tidy

31,627 posts

157 months

Friday 18th December 2020
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Court_S said:
The small tank is a pain the in arse. At first I thought it was brill that it didn’t cost much to fill up....I soon realised that I was just spending more time at the fuel station.
Yes, that is a pain.

My E87 1 Series and E86 Z4s only had 55 litre tanks, but my E46, E90 and E91 all had 63 litre tanks.

55 litres doesn't go far in a Z4M. laugh

LeeM135i

711 posts

84 months

Friday 18th December 2020
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Current long term ave over 20,000 miles is 34.4 mpg. Get an easy 40 mpg at 70mph on the motorway which is 75% of my driving. Good on the open A and B roads but really suffers in stop start traffic. Have seen single digits when pushing on at Brands Hatch. If you are driving it relatively easy you should see 30mpg without any issues.

Sticks.

9,713 posts

281 months

Saturday 19th December 2020
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Pebbles167 said:
Not exactly the same I know, but my dad bought an M235i Gran Coupe earlier this year. Regularly gets 30mpg mixed driving. Nudges 40 on longer journeys, and plummets when driving hard.

Impressive really, for a 300bhp car.
True. I had a M235i before my TTS, and get about 10% better mpg now.

JimBR

24 posts

129 months

Sunday 20th December 2020
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Best I’ve seen in a 2013 manual is 39.7 on a steady 60mph run.

In traffic round town you’re looking at 20-25.

rfn

4,609 posts

237 months

Sunday 20th December 2020
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I averaged 31.5mpg over 40k miles in mine (2014, 8ZF). So yes, you can get 30mpg! My previous 2013 8ZF also averaged north of 30mpg (5k miles).

Edited by rfn on Sunday 20th December 16:44