120d fuel economy
120d fuel economy
Author
Discussion

Petrol_fumes

Original Poster:

223 posts

241 months

Friday 9th January 2009
quotequote all
Right I was hoping you guys could put my mind at rest a little

Bought a 55 plate 120d from a dealer the week before Christmas. I use it as a daily runner which involves about 15 miles on the A1 and 4 miles from outer North London... cruising at between 70&80 on the dial (so 65-70 ish in actual speed) on the A1. I'm not managing to get any more than 38-40 mpg combined.

I've also zero'd it all on the motorway - cruised at the same speed and not got above 42mpg. Now i know in the wider context 42mpg is pretty bloody good, but not what I expected from the car.

Should i just stop watching the computer, or should I get it looked at?

cheers boys
t

B19GRR

1,980 posts

286 months

Friday 9th January 2009
quotequote all

CatherineJ

9,586 posts

273 months

Friday 9th January 2009
quotequote all
Our 120D never did any better than 37 mpg.

dibbly_dobbler

11,493 posts

227 months

Friday 9th January 2009
quotequote all
Petrol_fumes said:
cruising at between 70&80 on the dial (so 65-70 ish in actual speed)
Off topic here (sorry) but I found to my cost (£60 + 3 points!) that the 1er speedo is actually very accurate and only underreads by a few mph even at 70 odd. Just thought I'd mention it !

Welshbeef

49,633 posts

228 months

Friday 9th January 2009
quotequote all
If you put it into 6th at 45mph and hold it at that speed you will see mpg's well into the 70's mpg.


Diesel choice makes a big difference i.e. Tesco diesel in Telford oddly always gave me far more from a tank than Basildon Tesco... no idea why but over many years & many many tanks that was the case

Petrol_fumes

Original Poster:

223 posts

241 months

Friday 9th January 2009
quotequote all
Welshbeef said:
If you put it into 6th at 45mph and hold it at that speed you will see mpg's well into the 70's mpg.


Diesel choice makes a big difference i.e. Tesco diesel in Telford oddly always gave me far more from a tank than Basildon Tesco... no idea why but over many years & many many tanks that was the case
Weird!

Thanks guys, much appreciated

DarkMatter

1,503 posts

261 months

Friday 9th January 2009
quotequote all
Petrol_fumes said:
I'm not managing to get any more than 38-40 mpg combined.
I bought an 06 reg 120d auto a couple of months ago. Most of my driving is extra urban or rural. According to the on-board computer I've averaged 35.3 mpg but by keeping a record of the fuel I've put in and trusting the mileometer to tell me the miles covered I've actually averaged about 39.5 mpg. Still a bit disappointing compared with the BMW claimed figures, and my Audi A4 manual which averaged 48.5 mpg over 80k + miles.

Methane Bloke

264 posts

232 months

Friday 9th January 2009
quotequote all
I have a 56 plate 163 BHP, 120d manual with over 40K on the clock. My average is around 48 to the gallon and I "enjoy" driving it. I've found the fuel computer to be fairly accurate but my fiqures are based on tank fills against miles to keep the tax man happy.

CatherineJ

9,586 posts

273 months

Friday 9th January 2009
quotequote all
We also had a 330D Auto that would return 36 mpg day in day out. Our Mercedes A180D would constantly do mid 40's, which is why we were very disappointed with the 1 series, especially when you took into account BMW's own figures.

We have since purchased a Civic Type S 2.2 Diesel and we were expecting mid 40's. After 3.5 tanks of diesel and 1,200 miles we are currently on 38.6 mpg. It would have been higher but there was a lot of short local trips over Christmas.

We are hoping that now the car is back into it's normal routine and touch wood the weather warms up the economy will start to pick up.

mike325112

1,074 posts

214 months

Friday 9th January 2009
quotequote all
I get mid 40's usually, but found that it has dropped off to late 30's in this cold snap.

My trip computer usually mis-calculates under by about 5mpg as well.

niva441

2,166 posts

261 months

Sunday 18th January 2009
quotequote all
42 was about the best my 55 reg 120d ever achieved, despite trying hard to match the official figures. This was generally on dual carriageways and motorways, keeping the speed down and before rush hour, what should have been close to ideal conditions.

I'm guessing that was part of what Efficient Dynamics tried to accomplish, making the official figures more realistic.

Still that was the least of the problems I had with it.

Sticks2

9,709 posts

281 months

Monday 19th January 2009
quotequote all
niva441 said:
42 was about the best my 55 reg 120d ever achieved, despite trying hard to match the official figures.

Still that was the least of the problems I had with it.
X2 re my 07 facelift 120 auto.

wobert

5,574 posts

252 months

Monday 19th January 2009
quotequote all
My '05 120d with 68k miles on the clock averages 44-45mpg (worked from proper numbers not the computer) on my twice weekly run to Brum and back. (Chester to B'ham along fats A roads and M/ways)

Tip only use 6th above 60 mph as below it's running below 1500 rpm and "off-boost". Remember with the diesel engine it's how much fuel you're putting into the engine (ie throttle position) not necessarily engine revs that matter.

Best I've ever had on the above run was 54mpg, but that was stuck behind a lot of wagons.

Welshbeef

49,633 posts

228 months

Monday 19th January 2009
quotequote all
wobert said:
My '05 120d with 68k miles on the clock averages 44-45mpg (worked from proper numbers not the computer) on my twice weekly run to Brum and back. (Chester to B'ham along fats A roads and M/ways)

Tip only use 6th above 60 mph as below it's running below 1500 rpm and "off-boost". Remember with the diesel engine it's how much fuel you're putting into the engine (ie throttle position) not necessarily engine revs that matter.

Best I've ever had on the above run was 54mpg, but that was stuck behind a lot of wagons.
IIRC the claimed for that is 48mpg and the 118d of that era 49/50mpg. So if you obtaining ball park claimed figs then you'd be into the 60's when you upgrade.

Petrol_fumes

Original Poster:

223 posts

241 months

Wednesday 21st January 2009
quotequote all
Thanks guys

It's a 55 plate 120d with 22k on the clock. The last tank averaged at about 39, but had 44 on previous tank

Just thought I'd ask the question.. it's much more fun than the Mk5 golf that came before it

R1-Jay

450 posts

213 months

Thursday 22nd January 2009
quotequote all
diesels usually take a while to warm up and get decent economy. you normally need to do a good 10 miles ateast to get the engine warm enough to see the benefits.

also, the OBC is not that accurate, my 320d only shows 36.2mpg over about 10k miles where as i have never got less than 500 miles to a tank which is about 45mpg

LocoBlade

7,653 posts

286 months

Thursday 22nd January 2009
quotequote all
There's a thread on babybmw.net at the moment about pre-facelift 120d fuel consumption, and it seems that some are significantly more economical than others, even taking different driving conditions into account. IIRC there was one report that a dealer update on the ECU (for an unrelated issue I think) made a significant improvement, but nothing concrete on a definite "fix". The facelift cars do seem to be a lot better though, I only picked up my 123d at the weekend and despite some new car enthusiastic driving when conditions allow, Im averaging about 42mpg according to the OBC, all on A and B roads with a bit of town driving.

niva441

2,166 posts

261 months

Friday 23rd January 2009
quotequote all
LocoBlade said:
IIRC there was one report that a dealer update on the ECU (for an unrelated issue I think) made a significant improvement, but nothing concrete on a definite "fix".
I wonder if they've done an ECU upgrade to sort the ABS, Engine cutout and gearbox lock up problems I experienced in mine?

PJR

2,616 posts

242 months

Friday 23rd January 2009
quotequote all
CatherineJ said:
Our 120D never did any better than 37 mpg.
You got shot of it before it was barely run it!

Welshbeef said:
If you put it into 6th at 45mph and hold it at that speed you will see mpg's well into the 70's mpg.
Christ, have you bought one at last!? Or are you basing your findings on another one of your 10 minute test drives?




I've been pottering about in a 120D SE auto for 4 years or so. Although it hasn't done a great number of miles (only 17k or so). Its pretty decent on mpg for an auto. On a run I can coax a real 50mpg out of it. It really isn't so hot around town mind. I'd only get maybe 35mpg then. But even then, it's not so bad really? Being an auto, it's a good 5mpg worse off than a manual I reckon.
Still, despite the PistonHeads tradition of 1 series bashing, it's a great car smile My only gripes being iffy access to rear seats via the comedy back doors (5 door hatch) and the engine sounds like a London taxi at idle. But then find me a 4 pot diesel that doesn't.. Nice and quiet and pretty brisk too once on the move.
Handling is good, if a tad firm and jittery due to the runflats.

P,