Technical mpg

[gerbil1]

Good afternoon, this has probably been asked before but, i have a 2019 1.2 lounge which we have had for 3 year's it has always returned around 41 MGP around town and run it on E10 petrol but 2 weeks go we decided to try it on the E5 fuel as it is said to be better but the MPG has dropped to around 35 we have used that tank of fuel and gone back to E10 but have had no improvement. Can anyone give me any clue what to look at to improve things. Thanks for any help you could give. Kevin

 

[portland_bill]

Fuel consumption is very difficult to compare, or to pin down a cause when it changes, as it is affected by so many factors.
E10 has a higher methanol content, which has a lower calorific value then petrol, so worse fuel consumption is expected, and many people report an increase in fuel consumption. I was surprised that both my cars, the Panda and a 2015 Fabia, seemed to suffer no change with the transition to E10.
However, as we moved into a mild autumn, the Panda consumption improved, probably due to the aircon working less. But over the last week or so, the consumption has dropped noticeably, but this will be due to idling while scraping the ice off, and over the last few days, sitting in slower traffic as everyone goes shopping.

The Panda3, 2003-1012, has a tendency for the front calipers to get tight, or the pads to seize in their mountings. This causes the pads to rub on the discs, which as well as wearing the pads out faster, uses more fuel to overcome this. I've no idea whether the later model uses the same brakes, or if they suffer the same issues, but it might be worth jacking each wheel up, and seeing how easily each wheel spins.

 

[jrkitching]

Fuel consumption is very difficult to compare, or to pin down a cause when it changes, as it is affected by so many factors.

Exactly that.

A question for the OP - How are you measuring your economy?

 

[koalar]

Are you pressing the reset button on the trip computer more than normal

Because it’s an average one bad trip early on will require weeks or months to average out

Same if you have one good trip early on

The difference between E10 and E5 is less than 2%

Two professional drivers in identical cars on a test track over hundreds of miles wasn’t clear cut they had to normalised the averages to see any difference as 2% is within the normal variation in atmospheric and driving differences in normal driving


By the way I normally average over 60 mpg but that’s includes 50% on straight roads same car different driver rarely averages over 40 mpg

 

[MrMagoo]

I'm getting similar figures as the OP.
Before the advent of E10, I was regularly getting 43mpg, then 40mpg with E10, and now 35mpg in this cold weather.
My car has a new thermostat and heats up very quickly.

 

[jrkitching]

The difference between E10 and E5 is less than 2%

My own experience of premium fuels in a Euro4 1.2 Panda 169 is much better than that, but it's a complex subject and that doen't mean what works for me will work out well for everyone.

When the change to E10 came, I made the decision to switch to Esso Synergy Supreme+ (putatively an E0 fuel in many, but not all, parts of the UK) to see if I could detect any change from the supermarket E5 it had been running on for most of its life. This decision is constantly under review, but I've enough real world data to know that, for me, it's worth the extra cost, both in terms of economy and driveability.

I was surprised to see a pretty much instant improvement in both fuel consumption and bottom end torque. A quick check on the newly-reset trip computer showed a noticeable gain, and pickup from 25mph in 5th under a light throttle was definitely stronger. All this was obvious less than three miles after refuelling an intentionally near-empty tank.

I have a regular motorway journey of 100+ miles, and always start the journey from cold with the trip reset, which gives me a useful ongoing check on economy. (Incidentally, this was the first indication I had of a failing thermostat, when I saw an unexpected 10mpg drop). At a steady 55mph, on supermarket E5, I'd be looking at somewhere between 73-75mpg on the trip for a fine daylight journey. Only once, with exceptional care and highly favourable weather, I magaged 80.1mpg. Since switching to premium fuel, I've never seen below 80mpg on the trip in summer, and generally the figure is in the 82-84mpg range.

Real world figures are of course nowhere near that, but Fuelly does a running average over the last ten tankfuls, and that's moved from just over 55mpg on supermarket E5 to just under 60mpg on Esso Supreme+. If I get a minute, I'll pull up the figures and do a comparison between the last 12 months on supermarket fuel, and the first 12 months on Supreme+.

I'd say the difference is somewhere in the range of 5%-10%; enough to pay for the increased cost of the fuel. As the subjective driveability is noticeably better, I see no reason to go back.

So, what's going on?

I'd always thought that premium fuels would mainly benefit high compression engines being driven hard, but that isn't exactly true. If the ECU can adjust the ignition timing on the fly (and it seems the 1.2 FIRE can do this), then a higher octane fuel means the engine can run more advanced without knocking, and this improves both torque and economy. The big surprise for me was how much better the engine performed when pulling under load on a light throttle. I suspect most of the economy gains I've seen result not from the increased energy in an E0 fuel (the theoretical difference isn't that much), but from the engine's ability to run more advanced under load for any given throttle setting.

Your mileage may vary (quite literally!), but if you're an ecodriver, it might just be worth giving a premium fuel a fair trial. OTOH, if your driving style is to regularly use more than 2000rpm in the intermediate gears, you might not see much difference.

 

[09 johno]

I've been using E10 in my 2009 1.1 even though i'm against it i have a Motorhome and a minivan that 'need' E5 as they are to old for newer fuel so saving pennies went to E10 for the Panda as the prices skyrocketed and only using the Panda for shorter journeys. Since the weather has changed on the south coast to cold and now warmed up with wet moisture laden air, The Panda is not happy at all on E10, lost power, having to change down a gear compared to before when going up the same hills and hiccups until fully warmed up, there is also the higher fuel consumption but not doing 120 mile each way commutes anymore i cant really tell if this is down to the town driving. Next tank full is back to E0-E5 and continue with it from then on.

 

[MrMagoo]

Have you changed your spark plugs?
I changed mine and the difference was night and day; the little thing shoots off line.
Brilliant little engine.

 

[There all puntos]

I have used many a litre of fuel cleaning oily crap off of most of my endless car, motorcycle, pushbike and lawnmower parts.

Haven't noticed much difference using it as a cleanser. The wife's 12 plate Punto does feel a bit more sluggish it's 8v 1248cc engine (having to drop one to two gears to go up steep hills, as Glasgow is famous for such) is becoming much more frequent now. But returns approximately 62 real Mpg on a motorway run and about 34 mpg in urbane areas.

We don't rely of the average Mpg meter on the binnacle (as it's useless anyway) the more you press the throttle the more it decreases (with the wind behind you on a slight slope on a whiff of throttle, like driving down to Carlisle on the M74 once got 85 mpg) coming back uphill it showed 52 mpg.

We don't hammer it much, but the acceleration has decreased a bit but not much, if you don't mind building the cruising speed up slowly. Miss four and five star fuels. As we don't have any kids. And mother nature can kill at will anyhow. And she can look after herself. And we don't care about this crusty dirtball whirling through time and space.

Until the next rogue icey dirtball collides with the the moon or Glasgow.

So we're not saving anything, or anyone by using any new fuel. We have two woodburners and I burn most waste plastics and waste vege, damp and creosote coated old fences, that I pick up on gumtree for free.

 

[koalar]

I get 60-62 mpg regardless of fuel

Premium/supermarket/E10

Some do feel different though

That’s over tens of thousands of miles

The main reason you get high mpg because when you are coasting it cuts the injectors.

Make no difference if it’s E0 E5 E10 as none is entering the cylinders

Up to the VVT the fuel system is adaptive it alter the injector timings it compensates for air leaks and wear in the cylinders

The ignition timing is directly from a look up table depending on air density and temperature it does not know or care what fuel you put in it

I have no idea if the VVT and later are the same (probably)

If you are seeing a big difference between E5 and E10 something is wrong.

No significant difference in car fuel consumption between E10 and E5 petrol grades, Finnish study finds

A study conducted by Finnish researchers indicates that there is practically no difference between commercial petrol grades 95E10 and 98E5 sold in Finland as regards fuel consumption in normal driving. The finding is based on driving tests using six used cars of different make under laboratory...

www.sciencedaily.com

 

[There all puntos]

My Citroen Catnip gets 100 mpg (even thought it's a Ford engine) but it has oodles of torque. It can do over 38 mph in fifth gear on tick over. And like most modern injected engines, when you operate the throttle all your doing is metering in the airflow, as the CPU sticks the fuel and does the sums for you.

It weighs less than my old Fiat Stilo 1.4 (same length too) But when you drive around on tick over and attempt to get the magical 100 mpg. The Dpf fills up like a old Hoover Juniors dustbag and it slots the engine into limp mode, after it tries to do more than 60 mph on the flat.

Can't win them all, or where would you put all the medals and cups.

 

[gerbil1]

Thanks for all the reply's. We do reset the trip every time we fill up always have done and as i say it has been a constant 41 MPG and now it's down to 35 MPG when we do a long trip i check the trip against full tank to full tank and it as always about right last week it gave around 49 MPG where before it was 53/55 MPG. I know it doesn't mean much but it is always serviced at Fiat main dealer and was done in September. Have checked all the brake's and bearings all seems ok. Kevin

 

[jrkitching]

In the recent very cold weather we've been having, that drop isn't unusual, particularly if the car is parked outside and/or used on multiple shorter journeys.

Wait and see what happens after the next fuelup now that temperatures are a bit more normal.

 

[koalar]

Fuel consumption is very difficult to compare,

Correct

or to pin down a cause when it changes, as it is affected by so many factors.
E10 has a higher methanol content, which has a lower calorific value then petrol, so worse fuel consumption is expected, and many people report an increase in fuel consumption. I was surprised that both my cars, the Panda and a 2015 Fabia, seemed to suffer no change with the transition to E10.

Correct

However, as we moved into a mild autumn, the Panda consumption improved, probably due to the aircon working less. But over the last week or so, the consumption has dropped noticeably, but this will be due to idling

Correct

E10 was introduced late 2021 just as it got colder and the Internet forums fuel by miss information published in the newspapers .

while scraping the ice off, and over the last few days, sitting in slower traffic as everyone goes shopping.

I have noticed all Pandas are quite thirsty while idling

But it’s worth looking at the long term fuel trim at idle. If there is a slight misfire the ECU tends to max it out increasing the injector on time and drink petrol like crazy


Not my cars

My other half sticks it in her 125i and the fuel economy seems largely unaffected. According to the trip computer it’s dropped from 28.1 to 27.9.

Our 207 1.6 VTi didn't register any difference on the mpg

There is a 23 mile return journey I do at the same time of day on a Wednesday almost every week. On E5 the journey mpg read 50-52 every time. Since the forced change to E10 the mpg readout has been 47-49.
2018 Leon 1.4TSi (150). Can't detect any difference in performance or drivability. Strangely on longer journeys (over 100 miles) the mpg is unchanged.


I do the same A road and dual carriageway 35 miles to work outside of rush hour with very little other mileage in myVolvo c30 T5, so not really designed to hypermile.. And try to use cruise as much as possible so the journeys are pretty identical. All fuel comes from my local Ilminster Shell garage.

On E5 95 I managed a pretty steady 34.4 over the year. E10 95 seemed to drop it back to 33.8,

 

[koalar]

In the recent very cold weather we've been having, that drop isn't unusual, particularly if the car is parked outside and/or used on multiple shorter journeys.

Wait and see what happens after the next fuelup now that temperatures are a bit more normal.

Yep -8C

First time ever it’s not got up to full temperature in the first couple of miles

 

[vexorg]

mpg will drop in winter as it needs longer to warm up, you leave the car running to defrost, darker nights mean more electrical load. My citroen is usually 52mpg in the summer, and 48 in the winter, and you can see it drift up and down as the months go on.

 

[DaveMcT]

The Panda3, 2003-1012, has a tendency for the front calipers to get tight, or the pads to seize in their mountings. This causes the pads to rub on the discs, which as well as wearing the pads out faster, uses more fuel to overcome this. I've no idea whether the later model uses the same brakes, or if they suffer the same issues, but it might be worth jacking each wheel up, and seeing how easily each wheel spins.

I posted images of the brake discs from our 1.2. The pads had worn evenly (thickness). The outside face looked normal. The hub side face had a band around the middle of the pads with normal looking contact. The 10mm bands either side were badly pitted there was an almost imperceptible step in the pad face only detectable by touch.

Both sides were the same and both sides sliding pins were moving normally. I fitted new pads and discs but wont be surprised if they go the same way again. 100HP brakes (vented discs) with very similar looking calipers, have been fine.

 

[DaveMcT]

In covering the mpg. Make sure

Thermostat is opening oorrectly
Exhaust has no leaks within a metre of the catalyst outlet pipe.
Air filter is clean
All four exhaust stubs heat at the same rate from cold. If one pair is cool (IR thermometer) you need to check the ignition coils.​

I always use the posh petrol. It's more money but the car drives much better (yes you can feel the difference). I doubt it saves money but also doubt it costs any more per mile than the cheap crap.

 

[vexorg]

The air filter with have next to no effecton mpg or power.

As for posh petrol, pre-E10 then there was no difference to basic cars, highly tuned or more powerful turbos then yes, you could get more power out only if mapped to do so. The reports on E10 seem to be mixed, I've not noticed any difference in mpg or performance from the E10 - though some garages claims it's only legally E10, but may be somewhere inbetween E5 and E10.

 

[varesecrazy]

We have a panda twinair..
Generally the MPG readout is @56mpg

Swapped batteries recently..
Its not got above 48mpg

Almost certainly the Cold weather