Go faster for better MPG

[Paulr]

Since I have had my 2.5 auto Z4 I have driven it very carefully because I am still trying to get used to the 26mpg it has been returning.

However, was in a rush today and over 120 miles I gave it a fair old belting around the countryside and on the motorway - that straight 6 is terrific on song - and it ended up at 35mpg!

Beginning of the week I did have the engine management light come on, which I suspected was one of the exhaust sensors as I had put cheap supermarket fuel in it, so I put some fuel additive in to clean the cat etc, plugged in my new OBDII reader, confirmed what it was, and cleared the code. Light has not reappeared, put some Super unleaded in and that was the result!

 

[Marlon]

I like the title of this thread. Was the 26mpg average covering shorter stop start journeys?

 

[srhutch]

Try and stick to the same fuel. These cars seem to have very sensitive o2 sensors.

 

[chapeau]

Since I have had my 2.5 auto Z4 I have driven it very carefully because I am still trying to get used to the 26mpg it has been returning.

However, was in a rush today and over 120 miles I gave it a fair old belting around the countryside and on the motorway - that straight 6 is terrific on song - and it ended up at 35mpg!

Beginning of the week I did have the engine management light come on, which I suspected was one of the exhaust sensors as I had put cheap supermarket fuel in it, so I put some fuel additive in to clean the cat etc, plugged in my new OBDII reader, confirmed what it was, and cleared the code. Light has not reappeared, put some Super unleaded in and that was the result!

my 2.5 (it's a manual though) regularly averages around 29-31mpg per fill up when doing my daily driving to work and back. It's a mix of about 25% A road and 75% normal side roads. When I take it for a longer run though it can sit in the 40's if my right foot doesn't get too heavy. So it seems from my experience that what you've experienced is about right.
I only use shell v power nitro in mine as the manual says it's designed to run on 98+RON and it's not really that much more expensive than other regular fuels. Plus the cars 12 years old so I see it as looking after the engine and i'd much prefer that than risking it failing just to save a few pennies at fill up time.

 

[buzyg]

By a strange coincidence, this evening, my son worked out the MPG my old FiAT Coupe had managed around Nurburgring, 14 years ago.

Full 63ltr Tank 6 laps to empty, allowing a little unused, plus drive to and from the garage. 7mpg

You guys are just not trying hard enough. :wink:

 

[Chris_D]

High mpg is an acquired skill in any car imo, but totally attainable if you're willing to focus on your driving style.
I did a little exercise before laying up the zed a couple of months ago; set off on a 200km round trip and employed all the tricks in the book in order to attain the highest fuel economy i could - short shifting under 1800rpm, missing gears altogether- 1st to 3rd to 5th then 6th etc, coasting a lonnng way to a stop before junctions and red lights (pisses off people behind u but fk them), slipstreaming trucks at a max 60mph on the mway. I attained a not unreasonable 56.4mpg. From a 3.0l engine! That's way better than i used to achieve in my old E36 323i coupe eurotaxi, which was actually a detuned 325i, detuned for economy! Lol

 

[Jollyjoiner]

High mpg is an acquired skill in any car imo, but totally attainable if you're willing to focus on your driving style.
I did a little exercise before laying up the zed a couple of months ago; set off on a 200km round trip and employed all the tricks in the book in order to attain the highest fuel economy i could - short shifting under 1800rpm, missing gears altogether- 1st to 3rd to 5th then 6th etc, coasting a lonnng way to a stop before junctions and red lights (pisses off people behind u but fk them), slipstreaming trucks at a max 60mph on the mway. I attained a not unreasonable 56.4mpg. From a 3.0l engine! That's way better than i used to achieve in my old E36 323i coupe eurotaxi, which was actually a detuned 325i, detuned for economy! Lol
image.jpeg

Nobody likes a show off

 

[kis]

56! That's pretty epic!

I don't trust my OBC read out. I calculate the average mpg per petrol fill up. I've got a rolling chart to show how good/bad it is.

Most of my journey is motorway so I get 29mpg total average. Pretty happy with that for an over 10 year old 3.0 car!

 

[Chris_D]

56! That's pretty epic!

I don't trust my OBC read out. I calculate the average mpg per petrol fill up. I've got a rolling chart to show how good/bad it is.

Most of my journey is motorway so I get 29mpg total average. Pretty happy with that for an over 10 year old 3.0 car!

Been given a Mondeo 2.0 hybrid to use for a few months travelling between Germany and Holland and the average 65mpg puts any 50-odd mpg in the zed to shame!
wish the zed had the mondeo's park assist - it's spooky to watch!

 

[Chris_D]

High mpg is an acquired skill in any car imo, but totally attainable if you're willing to focus on your driving style.
I did a little exercise before laying up the zed a couple of months ago; set off on a 200km round trip and employed all the tricks in the book in order to attain the highest fuel economy i could - short shifting under 1800rpm, missing gears altogether- 1st to 3rd to 5th then 6th etc, coasting a lonnng way to a stop before junctions and red lights (pisses off people behind u but fk them), slipstreaming trucks at a max 60mph on the mway. I attained a not unreasonable 56.4mpg. From a 3.0l engine! That's way better than i used to achieve in my old E36 323i coupe eurotaxi, which was actually a detuned 325i, detuned for economy! Lol
image.jpeg

Nobody likes a show off

not showing off dear boy - merely demonstrating one's natural ability and prowess at being a (occasional) total miser!

 

[mmm-five]

Most of my journeys to work were 90% motorway, but throw in a few Welsh, Lakes, Scottish, German hoons, and a few track days, it makes my Z4MC consumption of 27mpg rather good.

I've tried the steady driving, but I just fall asleep, so consider it less dangerous to keep varying my speed and putting the boot in now & then - unless it's really heavy traffic where you're not going to get anywhere...then I'll divert off the motorway and find a twistier route home (usually cut off the M6 around Birmingham and come home across mid/north Wales A/B roads).

I regularly get over 30mpg on my trips to and from the 'Ring, but have also emptied a tank very quickly when cruising at 150mph in top. As buzyg says, you can use a lot of fuel on the track (and the 'Ring isn't the worst...by a long way), but my Z4MC is using about half as much fuel as the M5 - lucky for range & unlucky for cost the e34 M5 had a 90l fuel tank - over the same distance.

 

[kis]

I've tried the steady driving, but I just fall asleep

I know what you mean. If it's been a long week and I feel myself tiring then I'll take an earlier Jn exit so I can do some driving in town/country lanes so that I wake up.

If I can I stick it on cruise now. You can normally sit in the middle lane quite happily at about 65 and rarely adjust speed...

 

[Paulr]

What got me was that driving quicker and (seemingly) less economically, I got more MPG! I suspect that the fuel cleaner helped, and maybe it takes less fuel to quickly accelerate to speed, than to drift slowly up to speed.

I didn't buy it for economy though - all of yesterday was with the hood down & (should have made MPG worse) listening to that smooth straight 6 engine & enjoying the flow of the car. However, I am not made of money and recently gone self employed, do have to justify all my travel & fuel expenses more than usual. Good that belting the car helps!

 

[mmm-five]

It's not the increase in speed that makes it more economical, it's just that you're probably doing more cruising at the car's 'optimum' speed.

Driving around town, accelerating between 0mph and 40mph from 1st into into 3rd or 4th will always use more fuel than driving at a steady 60mph or 70mph in 6th.

Around town, I'm lucky to see 17mpg, due to the stop-start nature and getting 1500kg moving.

If you ever see any car with an instant MPG gauge, you will easily see what acceleration does to the economy - even my frugal Alfa diesel will show 20mpg when I hoof it, but then settles back to 50-70mpg when I go back to cruising.

 

[domsz4]

im too impatient to drive slow, accelerate slow. but I get 30s I think on my drives but its mostly motorway and there is that stretch on the m6 that's average 50.... I tend to block shift, 1, 3, 6 just keep it below 80 to drop to 3rd.

 

[Paulr]

I like the title of this thread. Was the 26mpg average covering shorter stop start journeys?

It was the last two tanks measured brim to brim, mix of almost every type of driving from town to country to motorway.

 

[Jollyjoiner]

High mpg is an acquired skill in any car imo, but totally attainable if you're willing to focus on your driving style.
I did a little exercise before laying up the zed a couple of months ago; set off on a 200km round trip and employed all the tricks in the book in order to attain the highest fuel economy i could - short shifting under 1800rpm, missing gears altogether- 1st to 3rd to 5th then 6th etc, coasting a lonnng way to a stop before junctions and red lights (pisses off people behind u but fk them), slipstreaming trucks at a max 60mph on the mway. I attained a not unreasonable 56.4mpg. From a 3.0l engine! That's way better than i used to achieve in my old E36 323i coupe eurotaxi, which was actually a detuned 325i, detuned for economy! Lol
image.jpeg

Nobody likes a show off

not showing off dear boy - merely demonstrating one's natural ability and prowess at being a (occasional) total miser!

Hahaha like ya style
Nothing wrong in being careful with ya money :wink:

 

[NickDE]

What got me was that driving quicker and (seemingly) less economically, I got more MPG!

Internal combustion engines get best efficiency at about 2/3 of max power. So either give plenty of gas or come off the gas completely - the pulse and glide method. And avoid braking as much as possible. One hell of a lot more fun than the 'don't accelerate and drive everywhere in top gear' method. If you're scared of acceleration buy a 1 litre Fiesta.

 

[Paulr]

What got me was that driving quicker and (seemingly) less economically, I got more MPG!

Internal combustion engines get best efficiency at about 2/3 of max power. So either give plenty of gas or come off the gas completely - the pulse and glide method. And avoid braking as much as possible. One hell of a lot more fun than the 'don't accelerate and drive everywhere in top gear' method. If you're scared of acceleration buy a 1 litre Fiesta.

A one litre Fiesta! Blimey, sounds a bit to fast for me. I'll get a 2CV, that should do the trick, and only 600cc.

 

[Smartbear]

What got me was that driving quicker and (seemingly) less economically, I got more MPG!

Internal combustion engines get best efficiency at about 2/3 of max power. So either give plenty of gas or come off the gas completely - the pulse and glide method. And avoid braking as much as possible. One hell of a lot more fun than the 'don't accelerate and drive everywhere in top gear' method. If you're scared of acceleration buy a 1 litre Fiesta.

Best efficiency is very different from best economy, max mpg is usually attained when the foresight & vision of an eagle is combined with the light foot of a ballet dancer
Rob