[AlanHo]

Two weeks ago I did a return trip from Solihull, West Mids UK to Newquay Cornwall - a round trip of 492 miles mainly on motorways and dual carriageway roads. The weather was dry with light winds and average temperature 8 centigrade. I set the cruise to 58 mph (verified by sat-nav). Fuel consumption for the trip was 52.1 mpg actual (full tank at start - brimmed refuel at end) - the computer showed 53.4 mpg.

Today I returned from an identical trip - again mainly dry, average temperature 9 centigrade - this time I set the cruise to exactly 70 mph (verified by sat-nav). Actual fuel consumption 48.4 mpg - computer 49.6 mpg.  The total driving time was just over 1 hour less than the previous trip.

Conclusion - the small saving in fuel cost of £5 by cruising at roughly 60 mph is not worth the extra time taken and the boredom of mixing it with the lorries. In future I will drive at the speed limit.

[Lorian]

You have an automatic?

Today I drove a couple of hundred miles on the M4 and M5 and averaged 67Mpg at an average of
about 70 miles an hour. No cruise, No real attempts to draft.

I'd never drive at 57mph on the motorway so no idea what the economy is like going that speed

To whoever followed me for a while in the red i30 hello

[AlanHo]

I have a manual gearbox. The car has done 4200 miles since new 5 months ago. I have never seen the computer show more than 55 mpg average no matter how carefully I drive. This was why I tried the long distance low speed cruise to see what effect it would have.

[eye30]

I remember they say driving at 56 gave the best mpg return.

so your test proves this is correct.




 

[AlanHo]

There is however a huge difference in fuel consumption with my car compared with Lorian's similar car. Other posters have suggested things get better after 10,000 miles. Do I wait to see if this is true - or do I go and make a fuss at the dealership?

The car was more frugal when I first had it and seems to have got worse on a long journey. I cannot imagine why
https://www.i30ownersclub.com/forum/index.php?topic=6613.0

[Lorian]

I'm pretty good at driving economically, and my car has over twice the mileage of yours.

I think you are giving something away using cruise too.

I don't think the dealer will be interested.

[rustynutz]

There is however a huge difference in fuel consumption with my car compared with Lorian's similar car. Other posters have suggested things get better after 10,000 miles. Do I wait to see if this is true - or do I go and make a fuss at the dealership?

The car was more frugal when I first had it and seems to have got worse on a long journey. I cannot imagine why
https://www.i30ownersclub.com/forum/index.php?topic=6613.0

Might be worth resetting the ECU.........

[Dazzler]

I think you are giving something away using cruise too.

I can drive quite a bit more economically in my Hybrid with the cruise off.. My cruise is quite agressive with the accelerator.. Haven't used the cruise in the CW to see if that is the same (Didn't have cruise in my diesel)

[rustynutz]

I agree, Daz....I find cruise is really only good on basically level country....otherwise, like you said, it's too agressive....

[BarryD]

You'd fail your driving test for cruising at 60 on a motorway these days AlanHo - it's called failing to make progress. 

Interestingly enough I was going to start a topic on driving styles and fuel economy.

I've kinda nursed my 1.6 diesel changing up at 1600 and being light on the throttle when pulling away, and it's settled quite happily on 50 mpg - great, the last couple of days though I've been late and in a foul mood and had some fun / pleasure out of the drive - so I've been using the mid / upper end of the rev band.  My fuel economy is for the last tank 54...

I'm going to razz the nuts of it for the next week / tank and see if I can make 57     

[AlanHo]

've kinda nursed my 1.6 diesel changing up at 1600 and being light on the throttle when pulling away, and it's settled quite happily on 50 mpg - great, the last couple of days though I've been late and in a foul mood and had some fun / pleasure out of the drive - so I've been using the mid / upper end of the rev band.  My fuel economy is for the last tank 54...

I'm going to razz the nuts of it for the next week / tank and see if I can make 57     

1  My car labours if I change gear below about 1700 and thus uses more fuel to accelerate
2  You have speeded up for the last two days - and got 54 on the last tank. Did you use a tank full in 2 days or what?
3  My bet is - if you now razz it - you will see a drastic fall in economy. My 1.6 CRDi 6 speed does about 46 mpg when I push it hard.

[BarryD]

[1  My car labours if I change gear below about 1700 and thus uses more fuel to accelerate
2  You have speeded up for the last two days - and got 54 on the last tank. Did you use a tank full in 2 days or what?
3  My bet is - if you now razz it - you will see a drastic fall in economy. My 1.6 CRDi 6 speed does about 46 mpg when I push it hard.

1.  The labouring seems to start below 1500, maybe the lower gears are different ratios in an older 5 speed?
2.  Unfortunately yes, got some family news that meant I needed to be in 250 plus miles North by tea time - and then back home again by 06:00 the following day.
3. 46 MPG when pushed hard -hmmm I could live with that after the Sante Fe 

[Lakes]

My cruise works good as the little diesel has good Torque if you got Torque thrusting you forward you don't need to use the throtle as much or shift back a gear 1,900 2,000 up the CRDi pulls strong enough to climb most hills

[mtuckeruk]

I have a CRDi 6 speed CW, 6000 miles. I have tried different speeds on long trips and get roughly 57mpg at 55mph, 54mpg at 60mph, 50mpg at 70mph

I agree with Alanho about changing gears at 1700rpm, this does not make sense as it forces the engine to labour, 2000rpm-2100rpm seems to be the sweet spot for me, which brings the next gear in roughly at 1500rpm, below 1500rpm it labours.

I have the Eco-Drive Indicator on my i30 and it seems to coincide with what I am saying. It says change up at 2100-2200rpm and it says change down at 1400rpm for gears 4th, 5th and 6th.

If I ride hard on my i30 which I did on a few tanks my fuel consumption goes down to 44mpg. Although you may need to reset the ECU after doing this if you want to get better fuel consumption on the next tank.

On my 6 speed CRDi I change to 4th gear at 31-32mph, to 5th gear at 41-42mph, and to 6th gear at 50mph, this should keep your revs just above 1500rpm and below 2100rpm

[Dazzler]

For a man with a very small brain (and I don't mean me  ) ... your post makes interesting reading 

[AlanHo]

It has been reported here in a number of threads that great care needs to be taken when brimming a diesel tank because fuel foaming cuts off the fill nozzle prematurely.

I filled my car a few days ago very early in the morning when there was no traffic about and the service station was deserted - I could thus take my time in filling the car. I filled until the nozzle clicked off - waited 30 seconds and filled again until the nozzle clicked off. I must have done this at least a dozen times before the tank seemed to be absolutely full and fuel was about to spill over from the filler. However I then waited for about 3 or 4 minutes and the fuel vanished down into the tank. I was subsequently able to put a further 3 litres of fuel into the tank - after thinking it was full.

I mention this because I have seen on this forum and on other motoring forums claims by people that their 1.6 diesel is doing up to 72 mpg on a long run and that they calculate this from a brimmed tank. Frankly - I find this hard to believe - they are either kidding themselves, not brimming the tank properly or I have a major problem with my car which has averaged 46.8 mpg since new.

I keep a spreadsheet of all fuel added to my car since new in September 2010. Here is a copy


http://img.photobucket.com/albums/v308/AlanHo1937/i30FuelSpreadsheet.jpg

[whitbomb07]

I find that after the 1st click, to brim the tank takes about another 12-13 litres........

It's all about how patient you are. 

Regards

Daniel

[mtuckeruk]

AlanHo I agree the people claiming 72mpg need to send in their logs books cos I just dont believe it either, i could maybe believe if they were driving at 50mph on a dead straight road on a slight downhill with no use of the brake whatsoever.

One disadvantage of been in the UK is that its colder than Oz and you wont get as good fuel consumption until the middle of summer. I find my car takes a while to warm up by which time I am half way to work. Also once you get past 15000 miles you should be getting better consumption. Rest your ECU by disconnecting battery.

 

[ElleB]

Sure does help if you can refuel your CRDI at a " quiet " time of the day!!.

Did so on the weekend and squeezed in 58 lts on the knocker, according to the pump . :o

I was a bit surprised, that is the most ever, but maybe it was still running on the sniff of the oily rag!!!

Re Alan's spreadsheet results, interesting to see the variation between calculated actual and the trip calculation.

 I am tossing up what "gauge to install as I do not have a consumption trip in our car, but once done it will be interesting to see. Tossing up between Scangauge 2 and the PLX DM-100/200.

 If you have not seen these, check our YouTube at this link.



Anybody using one of these PLX units, they look so "cool"
One would almost need a Co-pilot, since they operate through a toggle switch, and the temptation to check this and that reading as your cruising would be high and before you know it you will have an airbag in your face from a nose to tail "ding" !!

Cheers

[Dazzler]

Thanks ElleB... Sorry, but looks a bit like information overload to me... things on the screen changing too quick to comprehend.. :o

[Lakes]

Allan if you find it hard to beleave anything i tell you, try driving 812miles on one tank i have, & it was hill's mountains & plains & twisty but i limited speed to 58mph, also as i have had my car three years & covered 54,300miles and i have every recept from every fill up & when i fill right up from when the warning light comes on it's always within 1litre (4.54lt to one imperial gallon ) in Lt's it's always 56 to 57lt per fill up useing the same fuel ( premium diesel ) as this is low foaming.
but these days i just drive it & one tank is always about same distance. i think the motor likes warm weather the best as runs smoother in summer than in winter. also fuel is different summer to winter so impossible to directly compare the two countries so don't insult me!

[AlanHo]

Allan if you find it hard to beleave anything i tell you, try driving 812miles on one tank i have, & it was hill's mountains & plains & twisty but i limited speed to 58mph, also as i have had my car three years & covered 54,300miles and i have every recept from every fill up & when i fill right up from when the warning light comes on it's always within 1litre (4.54lt to one imperial gallon ) in Lt's it's always 56 to 57lt per fill up useing the same fuel ( premium diesel ) as this is low foaming.
but these days i just drive it & one tank is always about same distance. i think the motor likes warm weather the best as runs smoother in summer than in winter. also fuel is different summer to winter so impossible to directly compare the two countries so don't insult me!

The spec for my car states that the fuel tank capacity is 53 litres. On two occasions when I first had the car I deliberately ran it until it was virtually empty to check the capacity - and slowly filled it until diesel didn't foam and it overflowed from the tank. The one fill took 53.6 litres the other 53.07. Your car must have a bigger tank for you to be squeezing 57 litres in. I recognise that high mileage cars down under will be more economical because of the high temperatures compared with UK - but there are people here in the UK who claim to get more than 70 mpg in winter weather which I struggle to believe. I have tried very hard to drive for maximum economy - with and without cruise - and you can see the results in my spreadsheet.

If you are getting 812 miles from 56 litres - this equals 66 mpg. This is a far cry from the 72 mpg being claimed by a UK i30 1.6 CRDi owner and the 74 mpg claimed by a 1.6 Diesel KIA Ceed owner on other forums.  Why you think I was insulting you I find surprising since I was not aware of your fuel economy until your post above. And in there you are not claiming 72 mpg if you are doing 812 miles on 56 litres.

[Lakes]

The spec for my car states that the fuel tank capacity is 53 litres. On two occasions when I first had the car I deliberately ran it until it was virtually empty to check the capacity - and slowly filled it until diesel didn't foam and it overflowed from the tank. The one fill took 53.6 litres the other 53.07. Your car must have a bigger tank for you to be squeezing 57 litres in. I recognise that high mileage cars down under will be more economical because of the high temperatures compared with UK - but there are people here in the UK who claim to get more than 70 mpg in winter weather which I struggle to believe. I have tried very hard to drive for maximum economy - with and without cruise - and you can see the results in my spreadsheet.

If you are getting 812 miles from 56 litres - this equals 66 mpg. This is a far cry from the 72 mpg being claimed by a UK i30 1.6 CRDi owner and the 74 mpg claimed by a 1.6 Diesel KIA Ceed owner on other forums.  Why you think I was insulting you I find surprising since I was not aware of your fuel economy until your post above. And in there you are not claiming 72 mpg if you are doing 812 miles on 56 litres.

Alan I apoligize, i thought you were directing this at me, i did not know about these claims.
well my car is supposed to have a 52 or 53lt?? tank but from the time i first got it and filled the tank i have just about always filled it till i could see liquid not foam right to top of filler neck. but i know this is not compleatly filled as i have drived say 3kilometers then checked and tank is not compleatly full to top of filler ( must be air pockets somewhere ).
the only thing i could think of that you can only get 53L to compleatly full from empty and i get 57L is i might be getting ripped off from in- accurate measuring at the pump ( possible ).
& thanks for taking the time to do the spread sheet.

[AlanHo]

Last Sunday we did a 274 mile round trip to visit family for lunch – mainly on the M42 and M5 motorways to near Bristol. This is on identical roads to the trips I mention in my opening post – but a bit shorter. It was a dry day, fine weather, light traffic and I replicated the previous journeys by setting cruise to 60 mph.

The trip computer recorded an average of 56.1 mpg for the round trip – I just brimmed the tank today having done about 30 miles on local roads since Sunday and the trip computer now shows 55.3 mpg. Actual brim to brim calculation works out at 54.1 mpg – the best the car has achieved since new and an improvement of about 2 mpg.

However – as mentioned in another thread – I fitted new Yokohama low noise tyres to the car last week. I suspect that the new tyres are responsible for the 2 mpg improvement. If so – it helps me to justify the cost of the tyres because the reduction in noise, although significant, is less than I had hoped for.

[eye30]

The trip computer recorded an average of 56.1 mpg for the round trip – I just brimmed the tank today having done about 30 miles on local roads since Sunday and the trip computer now shows 55.3 mpg. Actual brim to brim calculation works out at 54.1 mpg – the best the car has achieved since new and an improvement of about 2 mpg.

Did you zero the trip computer?

If not it takes an ongoing average and depending on the trips you take and the weather, warmer gives a better return, this can have a influence on the read out.

I once returned, I think 65 mpg on a motorway trip, no stopping, no idle etc.

[Dazzler]

Last Sunday we did a 274 mile round trip to visit family for lunch – mainly on the M42 and M5 motorways to near Bristol. This is on identical roads to the trips I mention in my opening post – but a bit shorter. It was a dry day, fine weather, light traffic and I replicated the previous journeys by setting cruise to 60 mph.

The trip computer recorded an average of 56.1 mpg for the round trip – I just brimmed the tank today having done about 30 miles on local roads since Sunday and the trip computer now shows 55.3 mpg. Actual brim to brim calculation works out at 54.1 mpg – the best the car has achieved since new and an improvement of about 2 mpg.

However – as mentioned in another thread – I fitted new Yokohama low noise tyres to the car last week. I suspect that the new tyres are responsible for the 2 mpg improvement. If so – it helps me to justify the cost of the tyres because the reduction in noise, although significant, is less than I had hoped for.

A good result all around Allan 

[AlanHo]

I zero the trip computer each time I brim the tank. On the latest long run I brimmed the car at the start of the journey and brimmed it again today to check the actual consumption.

I have now reset the trip for the next tank.

I did a 40 mile trip on the motorway this afternoon and set the computer to give the instant read-out. With the cruise set to 60 mph on a flat section the computer showed 64 mpg - but this fell to as low as 42 mpg on the slightest incline. Downhill it showed 999.9 - not using fuel. On a relatively steep hill (for a motorway) it dropped to 36 mpg as the cruise gave it more throttle to maintain speed.

I am still bemused that my car is well short of the economy figures claimed by some other drivers here and look forward to it improving with mileage and in warmer summer weather.

[BarryD]

Mine seems to have settled on 51.5 from the trip computer, not as good as I hoped but still 15 mpg more than the old Santa Fe.  Often these days the M1 eoll along at below 50 due to broken down cars / jams etc..  I really hope to see a few MPG more once I do some more longer runs.

[rustynutz]

I filled up this afternoon and managed to put in 59.85 litres... 

Love to know how much fuel was left in the tank when I decided to fill up....
The countdown of the kilometres left to empty had gone walkabout and was showing  _ _ _ _ At a guess I reckon I did another 20 k's or so once that appeared... :-\