[Closed] MPG real figures

Ok

I have been doing some more reading it seems bimbling along is ok

also some say slipping it out of gear and coasting along will save petrols, lots of petrols

HOWEVER ....BEEEJESUS

the arguments caused amongst motorists on variouis forii about coasting versus not in or out of gear wear on clutch etc etc...its like the trail coming alive debate.

now I am lost

philxx1975 - Member

Ok

I have been doing some more reading it seems bimbling along is ok

also some say slipping it out of gear and coasting along will save petrols, lots of petrols

HOWEVER ....BEEEJESUS

the arguments caused amongst motorists on variouis forii about coasting versus not in or out of gear wear on clutch etc etc...its like the trail coming alive debate.

now I am lost

Forget about it. A modern car will know when it needs fuel and when it can preserve it so even if you're in gear and coasting it'll cut the fuel pump and let gravity turn the engine over.

Ah Good to know JimJam

if you need to stop (lets say you can see some red traffic lights in the distance for example) then entering deccel Fuel Shut Off by fully releasing the accelerator pedal whilst staying in gear with the clutch engaged is the best option (because the engine is using no fuel)

However, if you don't need to stop, then it's better (in terms of ultimate economy) to freewheel in neutral with the engine idling (it's best to free wheel in neutral with the engine off of course, but rather more dangerous). This is because what matters "on average" is to have the lowest possible drag and hence lowest average road load. Spinning the engine takes a surprisingly large amount of power. For a typical 2.0l family car, spinning the engine at 2000rpm takes about the same amount of power as it does to drive the car at a steady 40mph on a flat road!

Some of the latest auto/dsgs transmissions include a "sailing" mode, where they freewheel in neutral if you lift the throttle at high speed (eg on a motorway descent etc)

I'm in the 'leave it in gear and roll' camp but I got through to the final of a driving competition at work held at Millbrook Proving Ground, and the guy who won the economy run went against the advice of the assessor and coasted as much as possible! It was included stop start city driving, the Alpine section and a fly around the high speed bowl.

Some of the HGV's now come with a clever Auto box that allows the truck to coast in neutral whilst on cruise control so there must be some mileage (!) in it.

What I've found remarkable is that my wife's M135i and my 335d are so similar in consumption. 31 vs 33mpg. Remarkable in that in the 9 years since they built my 335, petrol engines have come on such a long way in efficiency terms that a modern twin turbo 3l petrol is (almost) as good on fuel as a 9 year old twin turbo 3l diesel.

Try lifting off the tiniest amount you can manage, so that the passengers don't even notice. You'll slow down only imperceptibly but your instant mpg will shoot up. You don't have to coast, even slight lift-off helps and you can do it for longer.

Gee - something wrong with your 335d I think!

molgrips - Member

Gee - something wrong with your 335d I think!

Nope - standard if driven like it's supposed to be.

Nope - standard if driven like it's [b]not[/b] supposed to be.

Something wrong with your left foot then.

Nissan qashqai 1.5 diesal get 60mpg no problem book claims 74 and I gave had 68 which I think is bloody amazing

Something wrong with your left foot then.

Not really. Have a look at Fuelly or Pistonheads MPG Wiki. 28-34 is the average for a 335d. Let face it, if you wanted economy, you'd have bought a 320ed, not a 300bhp, 3.0 twin turbo charged, 1.7tonne rocket barge.

I use an app called My Cars. Tell it how much fuel you put in, whether it was a fill up or partial, the odo reading and it comes back with mpg. Once it's got a few figures to work off it shows monthly/yearly mileage, cost, best/average/worst mpg.

My 1.9 CDTi Vectra estate gets a fairly consistent 50mpg. No idea what the quoted figure is though.

Something wrong with your left foot then.

My 435d and 325i both return similar mpg, apart from on long motorway journeys were the 435 hardly drinks.

Well, having said earlier that MPG isn't really a big deal - in relation to depreciation especially - I'd just add that...

I managed to get 64.2mpg from a Golf 1.4 TSI 150 on a recent long journey (overall ownership figure is low 40s and the manufacturer average is c.50). I was well chuffed as this is better than even VW's "extra urban" figures. 🙂

It's running via a DSG auto and has radar cruise control, which moderates the accelerator with finer inputs than my foot can achieve. If you're happy travelling at 60-65mph and doing very slow, deliberate manoeuvres then it's quite possible to get great MPG from petrol engines IME; usually better than the manufacturers quote. I struggle to get near to average manufacturer MPG figures in any diseasel.

Small petrols are very sensitive to load in my experience, too. I get 45mpg in the same situations I'd usually get 55+ from in said Golf 1.4 if I'm carrying passengers and bikes on the roof.

My old supercharged Golf R32 would give the same figures no matter what the load. 😉

Ok, so 33 is mixed driving. Driven at a steady 70 on the motorway or autoroute it'll magic it's way up to 600 miles on a tank compared to 450 in mixed driving.

Honda NC700X (motorbike)

Honda claim 81.6mpg
http://www.honda.co.uk/motorcycles/range/adventure/nc750x-2014/overview.html?gclid=CIua5NW7jM0CFXEz0wodVZkMtg&gclsrc=aw.ds

Over 20,283 miles I've averaged 81.2, but from my last 2 months (1458 miles) Ive averaged 84.0mpg and I've seen 90.1mpg in the past on a full tank.
This is worked out figures, I don't have a trip computer. The vehicles I have had a trip computer on have never been accurate either.

The computer on my car is [b]wildly[/b] optimistic 🙂 It normally says 80+.

Real figure is almost always 56-58.

The car is old and crap and probably only worth £500. I do 80 miles a day commuting (nearly 20k miles pa). Fuel consumption is massively more significant than depreciation !

Nope - standard if driven like it's not supposed to be.

Something wrong with your left foot then.

That's typical. Plus the readout could be wrong. I get 35 mpg average out of mine but the dash displays closer to 33. You can squeeze 42mpg but then you might as well have bought a VAG 2.0L car and be doing 55mpg.