MK5 Golf GTI

All Things Mk5 => Mk5 General Area => Topic started by: B3n on May 24, 2010, 05:06:31 pm

Title: What the hell is going on my MPG has gone up
Post by: B3n on May 24, 2010, 05:06:31 pm
Hey folks

I thought id post this as im seriously surprised by the MPG ive been getting from my car.

When i first bought it just over a month ago i was getting on average 24mpg generaly driving around then when i was hoofing it around 18mpg.

Now the last week ive been averaging 32mpg generally driving and 25mpg when ive been hoofing it :confused: :surprised:

Now this has seriously surprised me and i dunno why its increased! my driving style hasnt changed but there are a few other factors ive thought of

Ive just added a Miltek cat back
I took the car on a long motorway journey which i dont think its done before
Ive gone through a few tanks of V-power so maybe im begining to get the benifits
The warmer temperatures
maybe ive got used to the car so subconciously ive learnt how to drive it smoother

Could any of the above be to blame? :signLOL:

Im definately not complaining its just surprised me

Ben
Title: Re: What the hell is going on my MPG has gone up
Post by: Poppa Dom on May 24, 2010, 05:12:16 pm
Is a remap also in the equation?
Title: Re: What the hell is going on my MPG has gone up
Post by: Norbreck21a on May 24, 2010, 05:15:16 pm
Dunno why, and I know it's against everything we have always been told, but my soot chucker does better the warmer it gets  :confused:

In the winter my mapped GT 2.0 TDI normally averages about 45-49mpg for my normal weekly mixed driving cycle. Over the last week however (with the warm weather) it's shot up to 56.7MPG  :jumping:

Don't know if it's because witht he warmer weather, it doesn't need to lean the fuel mix as much when the cars are cold (like the old chokes), or weather it's down to the fact that I''m not using headlights, wipers and heater seats at all lately ?
Title: Re: What the hell is going on my MPG has gone up
Post by: B3n on May 24, 2010, 05:16:29 pm
The car has got a REVO remap but this was done on the second day i had it :party:
Title: Re: What the hell is going on my MPG has gone up
Post by: Hedge on May 24, 2010, 05:17:38 pm
It could be that in the warmer weather the car spends less time on its 'cold start' cycle.
Title: Re: What the hell is going on my MPG has gone up
Post by: B3n on May 24, 2010, 05:28:11 pm
Yeah i have thought about the possibility of the warm up cycle but would this really make a difference of around 8mpg
Title: Re: What the hell is going on my MPG has gone up
Post by: Richn83 on May 24, 2010, 05:46:50 pm
Depends on the length of your journey, it double injects for the first minute to heat the cat up quickly, so that could be 8mpg over a short run, and with warmer air it will be injecting less fuel each time as the warmer air is less dense but doubt that has made much difference.

Using super could have made a difference as the engine will again be able to get more energy out of less fuel.  Maybe a combination of all the factors, like the new zorst makes a nicer sound at lower revs so you have started shifting up earlier!!  :evilgrin:
Title: Re: What the hell is going on my MPG has gone up
Post by: Nasir on May 24, 2010, 06:35:31 pm
I think it's definitely the fuel. The FSI runs best on super unleaded and the difference in MPG can be quite big.
Title: Re: What the hell is going on my MPG has gone up
Post by: Poverty on May 24, 2010, 07:52:07 pm
its the weather.

Warm air is less dense continous knock on effect blablabla
Title: Re: What the hell is going on my MPG has gone up
Post by: Neimad on May 24, 2010, 09:31:26 pm
I do a 35 mile run each way to work every day with roughly 60% spent on the M6 and 40% on other roads with varying speed limits; in the winter I can just about manage 35mpg but with good weather like the last few days I'll get anywhere between 35 and 41mpg using the same driving style (granny-esque :sad1:).

I know some folks on here swear by it but in the three years I've owned my GTI I can honestly say that on my journey the weather makes more difference than super unleaded ever did.  In the 85bhp Polo I had previously it didn't make all that much difference to fuel economy either, but you could definitely feel the difference in throttle response and pick-up.

Just my 2p...
Title: Re: What the hell is going on my MPG has gone up
Post by: Top Cat on May 24, 2010, 10:12:28 pm
Mine has gone down along with the windows and the right hand pedal.  :evilgrin:
Title: Re: What the hell is going on my MPG has gone up
Post by: mclovin on May 24, 2010, 11:13:52 pm
Hold on, if it's the weather how come I got much, much worse MPG figures out of my old Alfa GTV V6 when it was in Dubai compared to when I brought it back to chilly old Blighty?
Title: Re: What the hell is going on my MPG has gone up
Post by: Poverty on May 24, 2010, 11:17:09 pm
naturally aspirated car, and seeing as dubai is stupid hot cooling systems would be working overtime.
Title: Re: What the hell is going on my MPG has gone up
Post by: Richn83 on May 24, 2010, 11:26:42 pm
Not sure what the humidity is like in Dubai but high humidity wont help combustion.  Also altitude will have a bigger effect on normally aspirated cars, where as a turbo will help to counter the effects. 
Title: Re: What the hell is going on my MPG has gone up
Post by: Nasir on May 25, 2010, 12:18:21 am
Not sure what the humidity is like in Dubai but high humidity wont help combustion.  Also altitude will have a bigger effect on normally aspirated cars, where as a turbo will help to counter the effects. 

It's very humid in Dubai but most parts are just above sea level.
Title: Re: What the hell is going on my MPG has gone up
Post by: chungE on May 25, 2010, 11:13:38 am
It's due to the new V-Power that we been using!
Title: Re: What the hell is going on my MPG has gone up
Post by: Pullafacial on May 27, 2010, 06:57:34 pm
Fairly sure i've had a split DV for the past week and since then my MPG has increased from about 31 to about 36 on the same journey if that helps at all.

Steve
Title: Re: What the hell is going on my MPG has gone up
Post by: john_o on May 27, 2010, 10:14:50 pm
funnily enough , Ive noticed the same thing , decrease of fuel consumption of about 3-4 MPG (from 28 ish up to 33 ish MPG).
less cold start cycle I would presume as others have said, but needs to be around 10 deg C or more to have noticed the difference
Title: Re: What the hell is going on my MPG has gone up
Post by: Kinbin on May 28, 2010, 12:45:02 am
the ECU is a neural network... it learns.... its brainy.

by taking the car out on a prolonged motorway journey, the predominant driving posture applied during the journey is kinda imprinted into the ECU.

Suppose you hand your "pocket rocket" to your SO (aka significant other) for mild drives to the neighbourhood store, tesco, and to tea for a week, you will experience the definitive difference with a limp rocket when you get your car back.