Bad Fuel or what?.

[JMRS4]

Hi All, Got the new LCI M5 2014 model done 2400 miles so far, on easy roads to and from the golf club been getting 25MPG.
Anyway filled up with TESCO 99 and saw the fuel gauge going down quicker than normal on these same runs ( 25 miles each way) on duel carriageways.
Topped the car up and it brimmed at 19 MPG!!!!
Car seems to run ok, can't push it on this run ( to many old bill) could the fuel be Bad?.
Any ideas .

[Cambell]

I run my E60 M5 on Tesco 99Ron and its fine. Has anything changed ? Do you still let the car do the cold start routine before driving ? Mine guzzles fuel when its cold..

[JMRS4]

Cambell said:

I run my E60 M5 on Tesco 99Ron and its fine. Has anything changed ? Do you still let the car do the cold start routine before driving ? Mine guzzles fuel when its cold..

I just start it in the garage and drive, I never do less than 25 miles on a run so engine gets warmed up after 10 miles on the duel.
I will have to keep an eye on it and take it back if it does not improve, I have not changed route or driving style on this regular run which is 25 miles each way.

[pjv997]

I think you'll find that about 20mpg is a realistic average unless you drive like a granny

[stevesingo]

Tesco 99 has an 5% ethanol, 3% methanol content, both of which have lower calorific energy than petroleum. I don't know what fuel you were using previously, but it may be worth googling for data for comparison.

[JMRS4]

stevesingo said:

Tesco 99 has an 5% ethanol, 3% methanol content, both of which have lower calorific energy than petroleum. I don't know what fuel you were using previously, but it may be worth googling for data for comparison.

I used ESSO 97, it was good.

[JMRS4]

pjv997 said:

I think you'll find that about 20mpg is a realistic average unless you drive like a granny

What on pure Out of town driving, no way, I do not do town work, my mate drives in London traffic and gets 18 MPG.

[Locknut]

stevesingo is correct, fuels with higher ethanol/ methanol content will give poorer MPG. They also "go off" when stored which is why many lawnmowers will not start in the spring.

[kippaxking]

I've only done 200 miles in mine but my average is now 14mpg. That's with V-Power.

All this talk of 25-30mpg maybe a bit of a myth.

Amazing car though so I'm not complaining!

[JMRS4]

kippaxking said:

I've only done 200 miles in mine but my average is now 14mpg. That's with V-Power.

All this talk of 25-30mpg maybe a bit of a myth.

Amazing car though so I'm not complaining!

A Myth, No mate, I live out of town and get 25 MPG most times, even the borrowed 2013 Model M5 gave me this with 95 Ron sh*t fuel in it.

[JMRS4]

Locknut said:

stevesingo is correct, fuels with higher ethanol/ methanol content will give poorer MPG. They also "go off" when stored which is why many lawnmowers will not start in the spring.

This could well be my problem then Thanks will run on for another week on Esso/Shell.

[kippaxking]

JMRS4 said:

A Myth, No mate, I live out of town and get 25 MPG most times, even the borrowed 2013 Model M5 gave me this with 95 Ron sh*t fuel in it.

What am I doing wrong then? The car is in start-up 'Efficient' mode for 90% of the time. I do switch the auto stop/start function off - do you guys leave this on?

My 12 mile commute is all on 30mph roads with lots of slow traffic so that probably explains it. However, my previous 997 C2S was doing nearly 20mpg over the same route so I was expecting amazing things of the M5. I'm now getting 14mpg. Is that likely to improve as the engine is run-in?

(Even if it only did 5mpg I wouldn't swap it for anything!)

[pjv997]

kippaxking said:

What am I doing wrong then? The car is in start-up 'Efficient' mode for 90% of the time. I do switch the auto stop/start function off - do you guys leave this on?

My 12 mile commute is all on 30mph roads with lots of slow traffic so that probably explains it. However, my previous 997 C2S was doing nearly 20mpg over the same route so I was expecting amazing things of the M5. I'm now getting 14mpg. Is that likely to improve as the engine is run-in?

(Even if it only did 5mpg I wouldn't swap it for anything!)

I ran an E90 M3 for 3 years and had my 997 for 8 years. The mileage I got from both of them and my F10 M5 were all 19-20mpg. This based on living in a town in the Home Counties where I do a bit if driving in traffic, but most driving is A roads where some fun can be had or motorway driving where I keep with most people.

If your M5 driving is comparable to your 997, then your 14mpg doesn't sound right to me.

I am surprised by those who are claiming 25mpg plus. Part of my man maths to change from my M3 was that I might save some money on fuel, but that has not materialised.

[JMRS4]

kippaxking said:

What am I doing wrong then? The car is in start-up 'Efficient' mode for 90% of the time. I do switch the auto stop/start function off - do you guys leave this on?

My 12 mile commute is all on 30mph roads with lots of slow traffic so that probably explains it. However, my previous 997 C2S was doing nearly 20mpg over the same route so I was expecting amazing things of the M5. I'm now getting 14mpg. Is that likely to improve as the engine is run-in?

(Even if it only did 5mpg I wouldn't swap it for anything!)

I think you have "hit the nail on the head" 30 MPH is no way near the best speed for the engine, I find 75/80 MPH the best.

[kippaxking]

JMRS4 said:

think you have "hit the nail on the head" 30 MPH is no way near the best speed for the engine, I find 75/80 MPH the best.

I will follow your advice on my way home tonight

May get home a bit quicker as well!

[paulmc]

Have you noticed it any faster. My car seemed to change around 2800 miles. Before that it wasn't that fast, after that something deffo changed. I drive mine quite hard and it started to feel as quick as i though it should. My mpg has deffo got worse but can still over 20mpg on a quick 50 mile "A" road trip. Not tired a motorway run lately. I used to get 27-28 on the m way.

My average for 4k miles is 20.9 with a good bit of blasting about in that 4k

[JMRS4]

paulmc said:

Have you noticed it any faster. My car seemed to change around 2800 miles. Before that it wasn't that fast, after that something deffo changed. I drive mine quite hard and it started to feel as quick as i though it should. My mpg has deffo got worse but can still over 20mpg on a quick 50 mile "A" road trip. Not tired a motorway run lately. I used to get 27-28 on the m way.

My average for 4k miles is 20.9 with a good bit of blasting about in that 4k

Hi Paul , I am @ 2400 miles, car is very fast though.
Going for a long drive tomorrow to Corby and area, so see what the MPG is like then, still blasting but keeping an eye open.;)

[paulmc]

Just checked mine. 21.5 mpg @ 39.6 mph over 4067 miles

[Skrambles]

kippaxking said:

What am I doing wrong then? The car is in start-up 'Efficient' mode for 90% of the time. I do switch the auto stop/start function off - do you guys leave this on?

My 12 mile commute is all on 30mph roads with lots of slow traffic so that probably explains it. However, my previous 997 C2S was doing nearly 20mpg over the same route so I was expecting amazing things of the M5. I'm now getting 14mpg. Is that likely to improve as the engine is run-in?

(Even if it only did 5mpg I wouldn't swap it for anything!)

I get 18 mpg in bad London traffic (on 30 mph roads), without Start/Stop. I get mid to high 20s for mixed or motorway driving.
I've experienced the same mpg since I got the car, new, in May last year.

[JMRS4]

Skrambles said:

I get 18 mpg in bad London traffic (on 30 mph roads), without Start/Stop. I get mid to high 20s for mixed or motorway driving.
I've experienced the same mpg since I got the car, new, in May last year.

Blasted out that fuel yesterday , brimmed it, did a couple of 100 mile runs, brimmed it and 26MPG.
That was with some blasting.

No more TESCO Fuel for me.