WS Fiesta fuel consumption calculation

[doctamick]

Many of us have been quoting the average fuel consumption in our WS Fiestas, as calculated by the car’s trip computer (see http://www.fordforums.com.au/showthread.php?t=11263743). Has anybody compared these values with a simple manual calculation (i.e. using the distance travelled and the actual amount of fuel pumped into the tank)??

For the last few tanks of fuel, I have been resetting the odometer and average fuel consumption on the trip computer. My trip computer had been showing me what I thought were awesome fuel consumption figures (5.7 – 6L/100km!), averaged over a full tank, and doing mainly freeway driving. However, after doing the manual calculations, I have been very disappointed to find that the fuel consumption is consistently being under-estimated by about 10-15%!!!

Although 6.5ish L/100km is still pretty good, I wonder if this is a scam by the manufacturer to make us feel like the car is more economical than it really is. Has anybody else experienced this?

[dannyhilton]

Keep in mind when your car says it has 0km to go and is empty, there's still just over five litres of fuel still in the little sucker, IIRC? I think that's what I read? Gotta fill up tomorrow so I'll check that actually...

[zetec jim]

I've got a really good app on my iPod touch that calculates everything from price to kms and also averages it all out after every input. It's called road trip lite... And also remember that the manufacturers test figures are always extremely hard to replicate.

[macou]

I only have a CL, which means no trip computer (can they be fitted retrospectively??). Anyway, I will be keeping a log to work out the economy and will update when I fill up again. Had the thing 2 weeks and haven't had to fill up since I got it! Will keep you updated if anyone is interested?

[kiwijohn42]

How do you rate it Jim?
I use Gas Hog. Shows a solid 7L/100km for the last 20000km in my WQ Zetec.

[zetec jim]

yeah, i'm finding it pretty good, i'm also averaging 7L/100km... but thats only over 1500kms, and with a trip down to port fairy thrown in there (which averaged 6.3L/100km which i was quite happy with)

[Vision Zetec]

Mine started at 14L/100km when i picked it up from the dealer lol :/

It is down to 9L/100km now after driving about 250km's. I have an excel spreadsheet handy for when I fill up, I will let you know of the results when the time comes

[Candyman2]

Ours is getting the factory quoted numbers as measured by the MFD and using km's travelled/L's filled (both match quite well). Mix of city crawl and some M2 riving.

Drove it hardish from new, oil change (engine and gearbox) at safety check up, tyre pressure checked (dropped a bit first 1,000 km) and run on Caltex 98 since new.

[doctamick]

Thanks for the replies. I am keen to see the comparison between your fuel consumption shown on the trip computer, compared to that calculated for one or more full tank(s) of fuel. Obviously, the average fuel consumption on the trip computer should be reset at the start to allow the comparison.

E.g. the last tank my trip computer showed 6.1 L/100km, but I calculated 6.8 L/100km based on 40L filled and 585km travelled.

[Twinpiston]

I know I am getting around 650 travelled on 41 litres, can sometimes push it out to 700 for 43 used...

I think I got a very economical one though!

[pitpal]

Trip computer showing 7.0 exactly on the WS fiesta. 95ron and 50\50 freeway,city driving. 10k on the odo so by now shes run in and loosened up. Happy with the economy and performance, as shes not babied when driven

[Spinner77]

Forgive my ignorance, Candyman, but was the safety check at 1500 or 3000 km?

Did you also change the filter?

When you say you have driven it "hardish", did you keep an eye on the revs?

I have to say that how to run in a car properly seems to be one of the greatest unresolved mysteries of life, given the totally contradictory opinions out there.

[Candyman2]

Originally Posted by Digger77

Forgive my ignorance, Candyman, but was the safety check at 1500 or 3000 km?

Did you also change the filter?

When you say you have driven it "hardish", did you keep an eye on the revs?

I have to say that how to run in a car properly seems to be one of the greatest unresolved mysteries of life, given the totally contradictory opinions out there.

http://www.fordforums.com.au/showpos...7&postcount=14

Filter changed as well.

I rarely drive to the rev counter, I drive according to the sound of the engine and feel of the car.

Agree about info on running in but I've gone with advice of mechanics I trust and my Subie tuner - most of the "run in" occurs in the first few hundred km's in terms of how the driver can impact run in. Engine and other components (engine, gearbox, brakes, steering) are never laboured or used excessively but neither are they babied.

[Spinner77]

Interesting, Candyman.

Do you use synthetic oils?

[Candyman2]

Originally Posted by Digger77

Interesting, Candyman.

Do you use synthetic oils?

Full synthetic went in the engine.

Redline MT90 in the gearbox.

Cheers

[Spinner77]

Thanks, Candyman.

[Vision Zetec]

Ok so just filled up for the first time!

Trip computer said 8.6L/100km, my calculations say 8.2

That was driven around town mostly and babying it. I did do WOT once tho at the end of the tank!

Will see how the next tank goes, filled up with V-Power

[macou]

I had my second proper fill up yesterday, the first one that would give me some accurate data. Here are the results;

Distance Travelled 529km
litres put in 35.8l
Litres/100km = 6.77

These results are for my WS Fiesta 1.6, 5 speed Manual (3 door), mostly suburban driving and not driving conservatively. I intend to keep a log for a while to see if it flucuates, but on first results it I'm relatively happy.

[csv8]

I must have a sick Fez, but dealer reckons all is ok. Latest fillup 234kms for 18.62l=7.95l/100kms. !!!!

[macou]

Originally Posted by csv8

I must have a sick Fez, but dealer reckons all is ok. Latest fillup 234kms for 18.62l=7.95l/100kms. !!!!

What kind of Fez do you have?

[Vision Zetec]

I'm half way through the second tank and the trip computer says 7.7L/100km

Not ideal but better than the first tank so can't complain too much

[dannyhilton]

There are a few people with manuals who don't get those figures Vision Zetec, so I'd be pretty happy with that!!! Not bad at all.

[zetec jim]

Remember too everybody that factory figures are achieved by experts in how to squeeze every last inch out of every millilitre of fuel...

[Vision Zetec]

Yeah thinking about it more 7.7 is pretty good considering the auto 1.4 is "rated" at 6.9L/100km

[csv8]

Originally Posted by macou

What kind of Fez do you have?

WQ Zetec auto is what I have...

[Candyman2]

Originally Posted by zetec jim

Remember too everybody that factory figures are achieved by experts in how to squeeze every last inch out of every millilitre of fuel...

Australia uses the European emissions standard/fuel consumption regime, the UN ECE Type 1 test (changed in 2003. It's now part of Australian Design Rule (ADR) 79/01; the fuel consumption component, including the label, is incorporated in ADR 81/01. Further modifications were made recently (last few years)

As late as this year, revisions are happening. For example, it is proposed that ECE R101 Revision 2 is adopted so that vehicle manufacturers would be required to provide six test results for certification purposes, compared to the two required under ADR81/01.

They are done in laboratories, not on the road. Manufacturers conduct the tests and supply the numbers to the federal departments of transport and environment.

Having said that, our Fiesta manual is pretty much on the mark now.

[Ben85]

Originally Posted by csv8

I must have a sick Fez, but dealer reckons all is ok. Latest fillup 234kms for 18.62l=7.95l/100kms. !!!!

8L per hundred for an automatic. Thats pretty good i reckon. Was it city or highway driving? If i'm doing city driving i get about 8L per hundred for my Manual. I get about 6L/100kms on the open road.

[zetec jim]

There you go!!! They're putting our fiestas on scaled up excersise wheels in the lab!!! Those crazy Germans...

[csv8]

Originally Posted by Ben85

8L per hundred for an automatic. Thats pretty good i reckon. Was it city or highway driving? If i'm doing city driving i get about 8L per hundred for my Manual. I get about 6L/100kms on the open road.

City driving..Ipswich Motorway,,Oxley to Buranda..so reasonable time at 90km/hr. Its not as economical for a small car as it could be. My WP auto did better.

[BruceT]

Hi CSV8,
"WQ Zetec auto is what I have..."
Sounds about right for mixed city-motorway driving. I did that in a 1999 Hyundai Excel (now deceased), and got 9.5-10 L/100 based on odometer vs bowser.