35IS MPG Figures?
- Thread starter sunnydays
- Start date
15 mpg??? .... if I thought mine only did that much I'd chuck it in a skip! ... 
all depends how you drive it, sure if fuel economy is your primary goal you can achieve high 20s, but then why buy a 340hp car, swap it for the 1.8 and get the same body with better MPG, never really understood the denial that the 35is is fairly shocking at full chat, using the instant mpg read-out mine shows 8mpg. If I take the same reading on overrun it shows 28.8mpg, guess that's the map. 30+mpg seems like a pipe dream in mine at least 
willgill said:all depends how you drive it, sure if fuel economy is your primary goal you can achieve high 20s, but then why buy a 340hp car, swap it for the 1.8 and get the same body with better MPG, never really understood the denial that the 35is is fairly shocking at full chat, using the instant mpg read-out mine shows 8mpg. If I take the same reading on overrun it shows 28.8mpg, guess that's the map. 30+mpg seems like a pipe dream in mine at least
There have been many posts on this subject and this one of the most sensible I have read , have never quite understood the obsession with MPG figures
willgill said:all depends how you drive it, sure if fuel economy is your primary goal you can achieve high 20s, but then why buy a 340hp car, swap it for the 1.8 and get the same body with better MPG, never really understood the denial that the 35is is fairly shocking at full chat, using the instant mpg read-out mine shows 8mpg. If I take the same reading on overrun it shows 28.8mpg, guess that's the map. 30+mpg seems like a pipe dream in mine at least
Thanks for the input mate, just to be clear in this scenario I am just utilizing the MPG figures to make sure nothing is leaking / wrong with the car performance wise. Everything appears to be okay, I went out of the way to drive it "gently" and managed 20 mpg +. Must just be my driving style that makes it go down to 15. Taking it on a motorway cruise tomorrow so will see what figures come back.
sunnydays said:willgill said:all depends how you drive it, sure if fuel economy is your primary goal you can achieve high 20s, but then why buy a 340hp car, swap it for the 1.8 and get the same body with better MPG, never really understood the denial that the 35is is fairly shocking at full chat, using the instant mpg read-out mine shows 8mpg. If I take the same reading on overrun it shows 28.8mpg, guess that's the map. 30+mpg seems like a pipe dream in mine at least
Thanks for the input mate, just to be clear in this scenario I am just utilizing the MPG figures to make sure nothing is leaking / wrong with the car performance wise. Everything appears to be okay, I went out of the way to drive it "gently" and managed 20 mpg +. Must just be my driving style that makes it go down to 15. Taking it on a motorway cruise tomorrow so will see what figures come back.
Sounds like you drive like me, if you cruise around 70 you should see 26/27mpg, if you sit behind a lorry at ~55 you might break 30, but where is the fun in that
You have mechanical issues with the car if you are seeing less than 25 during a normal week of mixed driving.
My car is mapped and I have sticky wider tyres and I still see 27mpg as a combined weekly figure. That's a fairly equal mix of stop start motorway congestion, stop start city driving and when the roads allow 90mph cruising on the longer motorway runs and hard runs through twisty lanes.
Newer cars may have tighter engines and see lower figures initially. And if you are unlucky enough to live in an area with permanent congestions like central London where you barely get above walking pace then I can see a case for low 20s or high teens but anyone getting 15mpg has an issue unless they commute on the Nürburgring. Probably leaking injectors or unmetered air getting into the car at some stage causing the fuel ratio to be out of whack.
I see people saying that they get low mpg because they drive the car how it's supposed to be driven. But in all seriousness you have to be a complete lunatic to be using all 300bhp the car offers at all times. Even then you should be getting more than 15!!
My car is mapped and I have sticky wider tyres and I still see 27mpg as a combined weekly figure. That's a fairly equal mix of stop start motorway congestion, stop start city driving and when the roads allow 90mph cruising on the longer motorway runs and hard runs through twisty lanes.
Newer cars may have tighter engines and see lower figures initially. And if you are unlucky enough to live in an area with permanent congestions like central London where you barely get above walking pace then I can see a case for low 20s or high teens but anyone getting 15mpg has an issue unless they commute on the Nürburgring. Probably leaking injectors or unmetered air getting into the car at some stage causing the fuel ratio to be out of whack.
I see people saying that they get low mpg because they drive the car how it's supposed to be driven. But in all seriousness you have to be a complete lunatic to be using all 300bhp the car offers at all times. Even then you should be getting more than 15!!
My daily 'drive' is from my bedroom, across the hallway and into my office, so when I drive my car, I drive it :lol:
Mine came back from a full service three weeks ago carried out by Ocean BMW in falmouth, they found no issues and my MPG hasn't improved or declined before or since, maybe some cars just run lean and others rich?
Mine came back from a full service three weeks ago carried out by Ocean BMW in falmouth, they found no issues and my MPG hasn't improved or declined before or since, maybe some cars just run lean and others rich?
You would have to be running extremely rich to get the MPG down that far. When my injectors started playing up my MPG dropped to 24~, then one day I noticed fuel running out of my exhaust so got them replaced.
The fuel ratio on these cars is very tightly controlled. The car measures free oxygen in the exhaust gasses using two O2 sensors, one in each pipe, it then calculates the Air Fuel Ratio(AFR) from that and tweaks the fuel trims for each bank dynamically to bring the AFR closer to what the DME is requesting, which is from 14.67 during light cruising to 10.87 during high engine load and high revs.
When cars get serviced they don't check everything, they just plug the diagnostic head into the car and read out error codes. Leaking injectors and air leaks in the exhaust don't bring up any faults so it's entirely possible that there is an issue.
Leaking injectors have a whole raft of symptoms, people usually notice a couple before they go pop. You can get a rich fuel smell from the exhaust, lumpy idle, poor mpg and fuel residue on spark plugs. If you have diagnostic software you can read the AFR in each bank during deceleration and see if fuel is leaking into the cylinder when the injectors should be closed.
An air leak in the exhaust is also difficult to spot. You can sometimes hear it if you get under the car while it's running but the only way to know for sure is to get the car on a ramp and take a look with a smoke tester. If fresh air is seeping into the exhaust before the O2 sensors the car will think that the exhaust gas coming from the engine has free oxygen therefore must be running lean, and will inject more fuel to compensate, which in turn will still show free oxygen as it leaking in through the exhaust so it gets stuck in a loop of adding more fuel.
The fuel ratio on these cars is very tightly controlled. The car measures free oxygen in the exhaust gasses using two O2 sensors, one in each pipe, it then calculates the Air Fuel Ratio(AFR) from that and tweaks the fuel trims for each bank dynamically to bring the AFR closer to what the DME is requesting, which is from 14.67 during light cruising to 10.87 during high engine load and high revs.
When cars get serviced they don't check everything, they just plug the diagnostic head into the car and read out error codes. Leaking injectors and air leaks in the exhaust don't bring up any faults so it's entirely possible that there is an issue.
Leaking injectors have a whole raft of symptoms, people usually notice a couple before they go pop. You can get a rich fuel smell from the exhaust, lumpy idle, poor mpg and fuel residue on spark plugs. If you have diagnostic software you can read the AFR in each bank during deceleration and see if fuel is leaking into the cylinder when the injectors should be closed.
An air leak in the exhaust is also difficult to spot. You can sometimes hear it if you get under the car while it's running but the only way to know for sure is to get the car on a ramp and take a look with a smoke tester. If fresh air is seeping into the exhaust before the O2 sensors the car will think that the exhaust gas coming from the engine has free oxygen therefore must be running lean, and will inject more fuel to compensate, which in turn will still show free oxygen as it leaking in through the exhaust so it gets stuck in a loop of adding more fuel.
I'll pop up my logs from carly and MHD when I get a chance, because I wouldn't know what a correct or incorrect AFR reading looked like! 
I still think it's standard fuel economy, the other cars I drive return equally rubbish economy, I always put it down to my Ricky Bobby syndrome - "I wanna go fast"
I still think it's standard fuel economy, the other cars I drive return equally rubbish economy, I always put it down to my Ricky Bobby syndrome - "I wanna go fast"
If you have MHD then that's perfect.
The MHD standard maps run slightly leaner than stock so the map won't be the cause of the problems. I think they target 11~ at full load which is about right for standard fuel.
If you have any logs then send them to me and I'll see if you have fuel issues. The best kind of log for diagnosing injector issues is a 5-10min drive with a warmed up engine and plenty of downhill coasting.
A standard WOT log in 3rd gear moving to 4th is also useful because you can see how well the fuel pump is coping and see if the fuel trims are behaving.
You need to have the following channels selected;
Fuel rail pressure
AFR Bank 1
AFR Bank 2
LTFT 1
LTFT 2
STFT 1
STFT 2
Throttle position
Along with the standard Boost req, Boost actual, RPM and "Ignition Cyl 1 crk*" along with Cyl 2/3/4/5/6 correction channels.
The MHD standard maps run slightly leaner than stock so the map won't be the cause of the problems. I think they target 11~ at full load which is about right for standard fuel.
If you have any logs then send them to me and I'll see if you have fuel issues. The best kind of log for diagnosing injector issues is a 5-10min drive with a warmed up engine and plenty of downhill coasting.
A standard WOT log in 3rd gear moving to 4th is also useful because you can see how well the fuel pump is coping and see if the fuel trims are behaving.
You need to have the following channels selected;
Fuel rail pressure
AFR Bank 1
AFR Bank 2
LTFT 1
LTFT 2
STFT 1
STFT 2
Throttle position
Along with the standard Boost req, Boost actual, RPM and "Ignition Cyl 1 crk*" along with Cyl 2/3/4/5/6 correction channels.
Smartbear said:V8 Animal said:
Hi, many people use V-power because of its cleaning capabilities, the detergents used clean the internals of your engine. Turbo engines especially can make more power using super unleaded also
Rob
Yep I heard all this but I don't believe it.
I have a SL which says to use 97 Ron I doubt the beemer does.
Anyway I've tried a few tanks with it and not noticed any drops or gains.
On a dyno you may see improvements.
If you don't do short journeys a lot I doubt it will clog up.
I'm not paying 10p extra per litre for nothing it's expensive enough.
Oh and the SL is a 5.5 Bi turbo kicking out 570 bhp and normal driving I get 20mpg.
It's your money
Whilst I said mpg doesnt matter, I definitely get more miles from a tank of v-power/SUL, stands to reason that the increased octane and active ECU will allow the computer to run the engine leaner so the increase in filling up cost levels out over time. I see the same in the rs6 that will give an extra 30 odd miles from a tank with identical driving styles and thats just shy of 600hp