What Mpg Are You Really Getting?

[Jan van de Wouw]

I think you're overreacting. If you look at the small print they ALWAYS

mention that the values shown are measures under certain circumstances.

Like "highway driving": they get the car up to speed and have it run at that

speed constantly. If an actual person drives a car on a road there's allways

fluctuations in throttle position, overtaking, wind, different road surfaces etc.

They also measure at relative slow speeds "Highway driving" is done at 90kmh:

when I'm on the highway I allways drive at 120 to 130kmh, which is less fuel

efficient, but safer, as EVERYONE is driving at that speed...

If you've done a lot of short trips consupmption also shoots up: I drive 2x 25km

a day from home to work and back, gives me about 5,0l/100km, but if I drive

"urban" with a lot of stop and go it can shoot up to 6,2l/100km or more.

But on average I still get 5,6l/100km on average, which makes me happy,

as my Nissan 100NX could take 12,3l/100km in the winter!!!

[stu0500]

best ive ever managed was 27mpg from my 1.3.i give it a oil and filter change every 1000 miles! Mobil one fully sync race oil

[Jan van de Wouw]

Oil and filter every ONE THOUSAND miles?

Or did you accidentally leave out a zero???

I think every 1.000 is a bit often. Not that it's bad,

but oil still isn't free and filters also add to the costs...

[Devil-ish]

Well having finally had to refill my petrol I worked it out and getting 47mpg - remembering that I'm driving in heavy traffic stoppin n startin all the time. I'm well pleased

[Gryzor]

I think you're overreacting. If you look at the small print they ALWAYS

mention that the values shown are measures under certain circumstances.

Like "highway driving": they get the car up to speed and have it run at that

speed constantly. If an actual person drives a car on a road there's allways

fluctuations in throttle position, overtaking, wind, different road surfaces etc.

They also measure at relative slow speeds "Highway driving" is done at 90kmh:

when I'm on the highway I allways drive at 120 to 130kmh, which is less fuel

efficient, but safer, as EVERYONE is driving at that speed...

Well, I know what you mean. And I should probably have cooled down a bit before posting.

In principle, I agree with you, and I do know that industry measurements are supposed to be taken with a grain of salt. But a grain of salt is one thing, a 75% difference is... what? And why was it, indeed, that after they changed the L-sensor the consumption came down considerably, even for just one tank? I looked at the report over at spritmonitor.de for all Aygos, I seem to have the second worst performance of them all! And some of the figures there, as well as in this post, sound like sci-fi for my standards...

[adilmon]

For what its worth, I sometimes think the urban mpg quoted by manufacturers is generally more significant than the combined figure. I have had a growing tendency to floor it up to the speed limit. Let's be honest, it's not that fun driving like the accerator is going to bite your toes off if you press too hard. I still use the engine braking when I can, look ahead to avoid unnecessary braking but that's about it.

I find it very reassuring that I can drive "as necessary" and still expect over 50 mpg. In reality, the lowest mpg I've ever recorded was 57.3mpg (4.9l/100km)

[Gryzor]

For what its worth, I sometimes think the urban mpg quoted by manufacturers is generally more significant than the combined figure. I have had a growing tendency to floor it up to the speed limit. Let's be honest, it's not that fun driving like the accerator is going to bite your toes off if you press too hard. I still use the engine braking when I can, look ahead to avoid unnecessary braking but that's about it.

I find it very reassuring that I can drive "as necessary" and still expect over 50 mpg. In reality, the lowest mpg I've ever recorded was 57.3mpg (4.9l/100km)

As I said... sci-fi, compared to my less-than-40mpg average :(

I agree with you on the urban value, though, because indeed even if you drive sensibly it's more difficult to restrain yourself and not max it out on the highway than to drive conservatively in-town.

Cheers

Gry

[Jan van de Wouw]

And why was it, indeed, that after they changed the L-sensor the consumption came down considerably

That's very simple if you know a bit about modern Fuel Injection.

The L-sensor (Lambda-sensor or O2-sensor is the same) measures

the amount of unused Oxygen in the exhaust. If there's too much the

ECU (Engine Control Unit) injects more fuel, if it's too little less is injected.

This gives for (allmost) perfect combustion and economy.

If your Lambdasensor breaks or gets disconnected the ECU notices and goes

into what some people call "limp home mode". It sets the mixture on the rich

side to make sure there's enough fuel to keep te engine running. It also turns on the

CE-light (Check Engine, amber, shaped like and engine) to let you know something's wrong.

Since the engine is now running rich not all fuel is burned constantlty, causing the exhaust

to smell like gasoline AND fuel consupltion goes up, as the unburnt fuel HAS been sucked

out of the tank even if it's not used properly. If your eonomy still is bad goe back to the

garage and have them read the ECU (again), maybe something else has gone bad,

maybe the Lambda went out again, it could happen. If the Lambda IS out again I'd

have them search further to investigate what causes the sensor to go bad so soon...

[Gryzor]

And why was it, indeed, that after they changed the L-sensor the consumption came down considerably

That's very simple if you know a bit about modern Fuel Injection.

The L-sensor (Lambda-sensor or O2-sensor is the same) measures

the amount of unused Oxygen in the exhaust. If there's too much the

ECU (Engine Control Unit) injects more fuel, if it's too little less is injected.

This gives for (allmost) perfect combustion and economy.

If your Lambdasensor breaks or gets disconnected the ECU notices and goes

into what some people call "limp home mode". It sets the mixture on the rich

side to make sure there's enough fuel to keep te engine running. It also turns on the

CE-light (Check Engine, amber, shaped like and engine) to let you know something's wrong.

Since the engine is now running rich not all fuel is burned constantlty, causing the exhaust

to smell like gasoline AND fuel consupltion goes up, as the unburnt fuel HAS been sucked

out of the tank even if it's not used properly. If your eonomy still is bad goe back to the

garage and have them read the ECU (again), maybe something else has gone bad,

maybe the Lambda went out again, it could happen. If the Lambda IS out again I'd

have them search further to investigate what causes the sensor to go bad so soon...

Exactly my point... that something is not normal and that, indeed, some checking is needed.

Btw, if I understood the mechanic's words correctly, they may even have not measured the consumption; changing the sensor seems to be the standard practice in such cases.

In any case, even though we agree on the practical outcome, your explanation is really nice; thanks indeed! going to sniff my Aygo's exhaust tomorrow!

Cheers

Themis

[Jan van de Wouw]

going to sniff my Aygo's exhaust tomorrow!

Don't take too deep of a breath :P No really, if you think you'll recognise the smell you can try,

but if it's really there you'll smell it without going to your knees in my experience...

And only try AFTER a drive, as both the Catalytic converter AND the

O2-sensor need time to warm up before they can function properly...

About them not measuring and just swapping the part, this seems to

be standard practice in garages nowadays. They read the computer,

get an error-code refering to "a" system and just replace that system.

If the fault persists they just change the next part "in line". Sad actually...

[Guest]

QUOTE

While the Aygo is a good car it's not an 80 mph+ cruiser. Slow to 65-70 - you'll get much better mpg and the extra time taken for the journey will be minimum

UNQUOTE

Ignoring, rightly or wrongly, the legality etc of travelling that bit faster Id have to say that I DO find it VERY hard to drive at 65-70mph on the motorway in a car thats well capable of doing so.The Aygo IS perfectly suited in my opinion to my daily drive and while yes, it is a bit buffetted by sidewinds Id much sooner try and swerve suddenly in it than my old Fiat Cinquecento Sporting at high speed.

I have a rental Aygo at the momment which has promted me to buy one as it as brilliant little car, but had a 90mph run last week for about 40 mile and the buffetting did affect the car a bit, however not nearly as much as the smart car i used to have, however on that car lobbing some bigger wider wheels on it made the world of difference, has anyone put wider tyres on when they have been due for replacement?

I imaging chucking some 165's or 175's on the standard rims will probably be of use to anyone who regularly travels on M'ways.......

[Guest]

Picked up new Aygo Platimun on Tuesday last week with 15 miles on the clock,

2st fill up 39MPG

2nd Fill up 41MPG

3rd Fill up 46MPG

Mostly 85MPH+ motorway miles thus far sometimes with a car full of people and stuff so quite immpressed with the way its going. Im hoping that it will settle at about 50ish, When there is some gentle local stuff added into the mix.

[adilmon]

Picked up new Aygo Platimun on Tuesday last week with 15 miles on the clock,

2st fill up 39MPG

2nd Fill up 41MPG

3rd Fill up 46MPG

Mostly 85MPH+ motorway miles thus far sometimes with a car full of people and stuff so quite immpressed with the way its going. Im hoping that it will settle at about 50ish, When there is some gentle local stuff added into the mix.

on a private motoway ;)

For the record, D-4D Aygo never dipped below 57 mpg so far

[hora]

hmmm mine is still 360miles to a full tank- regardless if I drive 80% motorways or mixed etc. What gives?

P.s. Majority of the time its just me in the car/no passengers

[PaulT]

hmmm mine is still 360miles to a full tank- regardless if I drive 80% motorways or mixed etc. What gives?

P.s. Majority of the time its just me in the car/no passengers

Also depends on how you drive and what speed you cruise at on the motorways. The little engine becomes quite thirsty at high revs.

Paul.

[feldman]

Which petrol are you using? I switched to V-Power a couple of months ago and now get 400+ miles per tank without trying.

[hora]

I'm being thick (worked it out). Funny, I filled from empty to full last week at Tescos and the car is sluggish. Just a tad but its not as peppy as it usually is.

[Jeffrz]

Hi,

So far I have had 51, and 52mpg from the tankfuls I have put in. I have a 40 mile varied journey to work about 10 miles M/way 15 miles a roads the rest stop and start. Quite happy with that. I am now trying to be super smooth ang gentle on the throttle and not break 65 on the motorway to see what diff it makes. I may also consider putting V-power in as an experiment. My previous Alfa retirned worse mpg on V-power (?) but my Celice used to get more on V-power!

Ho hum

Jeffrz

[walfice]

I think BP ultimate is waaay overpriced. Not sure about prices elswear in the country but near me BP regular is 105.9, ultimate is 118.9!!!! Over the road regular Shell is 103.9, V-Power 110.9.

Using ultimate would cost an extra £4.55 to fill up. Thats around the price of a gallon (50ish miles in an aygo). V-power all the way for me.

[bodywork]

My car is brand new and am getting 51/52mpg on mix of country roads and motorway (just over 80ish).Expected a bit better.Does it improve?Is it more sensitive than most cars to 70+mph?

I forgot to mention in my 'First 1000 mile ' report that 4th and especially 5th gear are SOOOOOO long.Was really expecting better economy....Despite giving the car the odd bit of welly I normally am quite light on the accelerator pedal ....

[bodywork]

My car is brand new and am getting 51/52mpg on mix of country roads and motorway (just over 80ish).Expected a bit better.Does it improve?Is it more sensitive than most cars to 70+mph?

I forgot to mention in my 'First 1000 mile ' report that 4th and especially 5th gear are SOOOOOO long.Was really expecting better economy....Despite giving the car the odd bit of welly I normally am quite light on the accelerator pedal ....

As a comparison for you, my Aygo has done 13.000miles, a Black, petrol version, the worst iv'e got is 50, and the best 59, O, it has an MMT box as well, hop[e this helps (bodywork)

[adilmon]

I think BP ultimate is waaay overpriced. Not sure about prices elswear in the country but near me BP regular is 105.9, ultimate is 118.9!!!! Over the road regular shell is 103.9, V-Power 110.9.

Using ultimate would cost an extra £4.55 to fill up. Thats around the price of a gallon (50ish miles in an aygo). V-power all the way for me.

Thanks for pointing that out. I now think BP have been rather cynical and hoped that consumers would simply attribute the price increase in cost with the tax increase and nothing else. In my outrage I considered removing the spare wheel from the car to save weight, but then thought it would be more pragmatic to only carry half a tank of full for the same weight saving

At this rate my next tankfull will be with supermarket ULSD diesel and Miller Oil Fuel additive (diesel sport 4) to try and smooth out the performance and push up the mpg. The fuel additive costs about £1 per tank, but if I save £10 over using BP ultimate, it will be worth it.

A full tank will give me about 480 miles.

[ViR2]

How the hell are you getting such good MPG? :) Mine is reading 47.8 imperial mpg acording to spritmonitor.de <_<

[PaulGP]

Have just filled up for the first time from new (full tank of standard unleaded from dealer) - have got about 52mpg - mainly A-roads & some town & not doing more than 65mph(as still running in). Am very pleased so far. Have put in 34 litres of v-power today & will look to improve on the first tank.

I think if you want more mpg then keep below 70mph. It is the national speed limit & why is the world & it's wife always in such a hurry. Some nutter overtook me & 3 cars in front today only to slam on the brakes at a corner then get stuck in traffic coming uo to a roundabout. Is it worth it???

I bought an Aygo mainly for economy - I'm going to lose that economy if I'm bombing around at 85mph everywhere.

Maybe I'm just getting old before my time or maybe more sensible???

[aygo-bloo]

...... Have put in 34 litres......

Wow, you ran that low on fuel. :o The tank capacity is only 35 Litres!