Real world mpg

Thanks Valeter, I would expect to be averaging 40Mpg in our SD4 Manual, which is 20% less than the quoted figures!!

I currently get around 18mpg-20mpg around town in my 335i Coupe, probably similar to what you can expect!! Although on a decent long run it can get up to 30Mpg+ on Motorway at decent Speeds

Anyway, I am keeping the 335i despite its Crappy Fuel Consumption and Obscene Road Tax!! I just Love that Engine, Its a Real Cracker!!! But it will be getting used a lot less and only doing about 4-5k miles when the Evoque comes

I have an Si4 on order for 1st March but given figures quoted on this thread I may change to the SD4 manual. I really want the petrol as I detest the sound of a diesel engine but the Si4 doesn't have a nice throaty sound to match the rubbish consumption. Though if I were to have to stomach a diesel I would prefer the auto!

For a world intent on bringing emissions down and saving the planet some vehicle manufacturers are producing vehicles which mpg wise are no better than 30yrs ago,the petrol mpg figures are no where near quoted by the manufacturer and the diesel fares no better,really with what has been posted on this thread have we been sold vehicles which have been mis described,dont get me wrong i love the vehicle but i was expecting a little bit better than my RRS.

Reset my trip and done a bit of driving around town today - 25.5 mpg! Getting a bit better at least . . .

(10-12-2011 09:39pm)The Valeter Wrote:  I have an Si4 on order for 1st March but given figures quoted on this thread I may change to the SD4 manual. I really want the petrol as I detest the sound of a diesel engine but the Si4 doesn't have a nice throaty sound to match the rubbish consumption. Though if I were to have to stomach a diesel I would prefer the auto!

I know this is a long thread, so apologies if this has been asked before, but have you had a test drive in the diesel? If not go back and give it a try, you've nothing to lose.

(10-12-2011 11:04pm)Evo-king Wrote:  I know this is a long thread, so apologies if this has been asked before, but have you had a test drive in the diesel? If not go back and give it a try, you've nothing to lose.

Yes I have. I drove the Si4 on the unleashed event then had 3 test drives in the SD4 Auto. I did think the SD4 auto was fantastic, pulled like a train & didn't sound as dull as my Freelander but I just love a throaty petrol sound though the Si4 does lack a proper throaty sound to be honest & that small fairly insignificant point alone could be the reason I change to diesel.

But then you have to consider that diesel is presently about 9 pence a litre dearer than petrol so that is as good as 40 pence a gallon & that i do a lot of short journeys the diesel losses some appeal!!

(10-12-2011 11:13pm)The Valeter Wrote:  Yes I have. I drove the Si4 on the unleashed event then had 3 test drives in the SD4 Auto. I did think the SD4 auto was fantastic, pulled like a train & didn't sound as dull as my Freelander but I just love a throaty petrol sound though the Si4 does lack a proper throaty sound to be honest & that small fairly insignificant point alone could be the reason I change to diesel.

But then you have to consider that diesel is presently about 9 pence a litre dearer than petrol so that is as good as 40 pence a gallon & that i do a lot of short journeys the diesel losses some appeal!!

Stick with your petrol choice........I would. The diesel is good but its not the most economical on short urban journeys. When I change I'll certainly consider the petrol, especially if they put the 300 in it as expected.

For those taking fuel consumption figures from the trip computer please do bear in mind that these are not real fuel consumption numbers but are actually derived from a pre-defined table of 'expected' results for a given throttle position/gear/speed and probably a few other variables too - don't be deceived. You will probably see the computer report odd fuel economy numbers like 29.4 for no apparent reason - its not the real world as it is just looking the data up.

The only reliable way to calculate the actual fuel consumption is to fill the tank with fuel - to the brim (so you can see it) & reset the trip to zero. The next time you fill up - brim the tank again and make a note of the number of miles (here in UK anyway) travelled and number of litres used.

Divide the number of litres required to fill the tank by 4.54 and the result will be UK (imperial) gallons used.

Divide the number of miles on the trip by the gallons used and you have the fuel consumption as MPG.

In truth unless the car was fitted with a very accurate fuel flow meter (it won't be) and could somehow know the quality of the fuel, humidity in the air and then compensate for road gradient and altitude it has little chance of calculating an even remotely accurate number.

Straydox, I suspect there's a few real measurements going on too!
eg: how does the car know how many miles range you have? - clearly it's able to measure fairly accurately how much fuel is in the tank.

I would think it is able to know how much fuel (pretty precisely) has been injected in to the engine.

That said - yes, agree, the only true way to know is brim-to brim & get the calculator out, + check the volume of fuel that you actually added - do you trust the petrol station pump reading? is the tank really full to the same level? is the temperature the same?

I'm not too sure of the RRE trip accuracy yet, but suspect it is giving a slightly high reading - just as most do!

NB - one other factor ... is the odometer correct?

I have only done 140 miles in my sd4 diesel auto so far but the trip is saying 23mpg ouch! It is an improvement on the 18mpg it said when the car only had 11 miles on the clock! I hope it improves a lot from that!