The experiment: Heavy foot v Light foot

racso1975

Filled up the car at weekend 70 litre tank and decided to see what the difference it would make mileage wise and time wise getting to work.

My car is a 407 1.6hdi 04. My commute is approx 120kms round journey Carlow to newbridge with the majority of it motorway.

So after filling up the tank the car said i should get 1020kms from the tank. The idea of this is to see what kind of extra milage i can get and how much longer i'd have to spend in the car by nor driving constantly at 120kph or a tiny bit above:p

So as a starting point i am driving the way i usually do and with half a tank gone i have completed exactly 500kms and commute time is aprrox 45 mins.

I'll keep this updated as i go along.

If anybody wants to join in or offer their constructive advice please do so

celticbest

I'd say you will have to use the whole tanks with your normal driving pattern & then fill up and use the whole tank again but this time with your new driving pattern.

This will give you an exact conparision.

Zubeneschamali

celticbest wrote: »

I'd say you will have to use the whole tanks with your normal driving pattern

I'd say you'll crack and go back to normal driving long before you use a full tank in economy mode :P

antodeco

+1 Celticbest

Alot of the time, the engine misreads the last part of your fuel. You will get a huge amount for the first half, but the second half can be considerably less.

I also cant believe you get 1020kms from a 70 litre tank. I only barely get 600kms from a 60L tank :mad:

racso1975

celticbest wrote: »

I'd say you will have to use the whole tanks with your normal driving pattern & then fill up and use the whole tank again but this time with your new driving pattern.

This will give you an exact conparision.

Yeah sorry thats the plan must not have made it clear. Will continue to drive like normal on this tank and on next fill i'll change to the the light foot

I should explain that by light foot i dont plan on going over 100kph on the motorway and no aggresive take off's or over taking. Just silky smooth driving

Hopefully i wont revert back as cant see the 2nd half of experiment lasting longer then 7-10 days

racso1975

antodeco wrote: »

+1 Celticbest

Alot of the time, the engine misreads the last part of your fuel. You will get a huge amount for the first half, but the second half can be considerably less.

I also cant believe you get 1020kms from a 70 litre tank. I only barely get 600kms from a 60L tank :mad:

Yeah i dont really believe them either. at the moment it say's i'll get another 600kms but half the tank gone i really doubt it. if i hit 900-950kms i'll be happy enough

Repolho

I've done something similar with my 1.6 TDCi focus in the past.

My commute is 50km each way, 32 km of which is on the motorway. The difference between 100kph vs 120kph on the motorway only section was approx and extra 60km per tank, with each journey taking an extra 3 to 4 minutes.

I get about 900 to 925 km per fill. I fill it whenever the light comes on but it rarely takes much more than 50 litres. Fuel range usually shows over 630 miles when tank is full.

rcdk1

antodeco wrote: »

I also cant believe you get 1020kms from a 70 litre tank. I only barely get 600kms from a 60L tank :mad:

I can't believe it either..... is it not too low?
1020km per 70L = 6.86L/100km = 41.13 mpg (UK)
Should a 1.6hdi doing motorway driving not be getting better mpg?

pajo1981

No need to empty the tank.

Brim it, use it, brim it again. The pump will tell you exactly how many litres you've used since your last brim.

Of course, the more you use, the more accurate your test will be.

pajo1981

rcdk1 wrote: »

I can't believe it either..... is it not too low?
1020km per 70L = 6.86L/100km = 41.13 mpg (UK)
Should a 1.6hdi doing motorway driving not be getting better mpg?

Didn't that 1.6HDi set a fuel economy record in a 308 a while back?

keithclancy

rcdk1 wrote: »

I can't believe it either..... is it not too low?
1020km per 70L = 6.86L/100km = 41.13 mpg (UK)
Should a 1.6hdi doing motorway driving not be getting better mpg?

Jaysus ... my 2.0D gets 5.6l/100km

mickdw

I can get down to 7.5L/100km in my 1.8T audi driving as softly as possible.
Driving as I usually do, it averages 10.5L/100km

keithclancy

mickdw wrote: »

I can get down to 7.5L/100km in my 1.8T audi driving as softly as possible.
Driving as I usually do, it averages 10.5L/100km

At 180km/h mine sucks about 14l/100 bloody expensive in the long term for very little benefit.

racso1975

rcdk1 wrote: »

I can't believe it either..... is it not too low?
1020km per 70L = 6.86L/100km = 41.13 mpg (UK)
Should a 1.6hdi doing motorway driving not be getting better mpg?

It's an argument i've always made. People buy a 1.6 thinking it is going to be more economic then say a 1.9 or 2.0 but i also own a 1.9 and have always said it is more economical then the 1.9. I know on the motorway it's about 55-58 mpg

I dont know much about bhp torque etc but the 1.6 is 110bhp and the 1.9 is 105 bhp.

Imo i think the engine is prob too small for the size of the car.

Might try to rob the other car back from my wife and see if i can carry out the same test on it.

sealgaire

antodeco wrote: »

+1 Celticbest

Alot of the time, the engine misreads the last part of your fuel. You will get a huge amount for the first half, but the second half can be considerably less.

I also cant believe you get 1020kms from a 70 litre tank. I only barely get 600kms from a 60L tank :mad:

I think you are mixing up KMS with Miles?
You can't possibly be only getting 600 kms to 60 litres. I've an old Scudo and get 1125kms to 80litres

mickdw

keithclancy wrote: »

At 180km/h mine sucks about 14l/100 bloody expensive in the long term for very little benefit.

You hardly drive everywhere at 180 km/h though.
I dont drive at those speeds tbh but I do like to get up to speed as quickly as possible.

keithclancy

mickdw wrote: »

You hardly drive everywhere at 180 km/h though.
I dont drive at those speeds tbh but I do like to get up to speed as quickly as possible.

Only for about 15-20 minutes on Cruise Control for the Autobahn part of my commute

merc3ps

You will go crazy doing a full tank at sedate speeds.

I also tried this with my Insight.

If I drive with a bit of gusto I get 68-72mpg.
If I drive normally I get 72-76mpg.
If I drive like a grandad I can get 74-78mpg.

On certain specific short trips I can get higher. One 25 mile trip on the motorway resulted in 89mpg.

Timmaay

One interesting way of keeping track of your fuel use is get an OBD bluetooth dongle (likes of This, and then get an Android smartphone (as cheap as 60 euros on prepay from vodafone), and download the Torque-bhp app, which will let you monitor the fuel consumption, vehicle speed, location, throttle position etc etc. Most modern cars will have an OBD port near the drives seat (an 04 diesel should definitely)

The Dagda

I can get 1200 km if i drive handy from a tank of diesel in my 04 A4 tdi 130, that's about 18l/km or 60mpg...

MarkoC

Theres nothing to prove, its well know fact that car takes WAY less fuel while driving on 90 km/h rather than 120km/h
No overtakings and drive slow behind the lorries and you see huge increase in mileage.
No reason to invent a bycycle

BostonB

Some cars have economy display. On one car I had the difference between 120 and 100 was huge, less so 100 and 80 or lower. You generally adjust you speed to match the traffic, unless theres a big difference. So sticking to a speed the rest of the traffic isn't doing might be harder then you think.

vectra

Out of curiosity I am trying this myself this week

Started today on a new tank

Normal driving gives me an average of 6.9L/100km
Today I am averaging 5.3L/100Km

Strangely enough I am still doing almost 120KPH
Easing the throttle to pass if needed only otherwise cruise past slower traffic.

Tank is showing 890Km remaining and driven 189km.

Should be interesting when I fill again

GTE

Gearing has so much to do with that.

My old 1.9 VE TDI will do 55 to 60 mpg if I want to but once I start driving hard and driving at 120 - 130 kph the engine is going at 2900 to 3000 revs and I get about 48. If I had a 6th gear that cut the revs down to 1900 I think I would be well back into the 50's.

Stealthirl

sealgaire wrote: »

I think you are mixing up KMS with Miles?
You can't possibly be only getting 600 kms to 60 litres. I've an old Scudo and get 1125kms to 80litres

my soarer got a best of 600km for a 75L fill 550 of that was @ a stedy 100kph on a moterway but then agen it is a old twinturbo 6 auto

tobsey

I've the VAG 1.6tdi in an Octavia and I get 5l/100km on a 39km comute from Swords to Dundrum mainly on the m50, rarely over 100km/hr. If I go through town I get just over 6l/100km in very little extra time and it's only 20km or so. Basically while the effecieny improves on the motorway the extra length means I still burn a lot more fuel. Also the €2 for the toll only adds to the extra cost.

Best effecieny I've got so far is 4.6l/100km from Citywest back to Swords. Almost all motorway and kept it below 100 all the way.

On Sunday morning drove to Ballinasloe almost all motorway but was doing 160km/hr on the M4/6 as I was running late. burning 7.5l/100km but saved myself 20 mins according to the Sat Nav.

I've done 1200km so far at 5.9l/100km average so happy enough with that as there is a mixture of long and short trips as well as heavy and light footed driving. It also seems to be improving as the engine is bedded in.

kerten

I managed to achieve 48 mpg on 2001 primera 2.0 petrol automatic at 6:00 am for 25 miles journey. I decided to not try it again for my nerves .

But my average is 29-32 mpg for this car with a light foot on 80% backroads+20% town.

I think instead of looking for most economical car on motorway. looking for most economical car for your driving needs makes more sense.

It all depends on conditions(traffic, weather, extra weight, type of road, etc) and driver of course.

My experience is best economy is around 80km/h constant speed at 5th gear. I think over that speed, air resistance is the reason for worse economy.

racso1975

Ok so the fuel light came on today and i have just gone into the red!!! reckon i'll get the trip home out of her anyway. Currently there is 875kms done so will prob have about 920-930 on it by the time i fill up this evening even though the clock say i should get 120 odd kms out of it.

thehomeofDob

I actually tried this the other week. I always drive brim to brim, and always keep a record of miles covered for each tank. I track it on Fuelly.com.

Anyway, I decided to drive like an old man for a full tank and see what I could get out of it. The car is a 2Ltr Rover 75 Diesel CDT (115bhp). Normally I would average about 45mpg, and that's my average since I got the car. With a very light foot and a reduced speed of about 10% under the speed limit on motorways and exactly the speed limit on all other roads I got a whopping 700miles (1130km's) out of 57litres of fuel. 55mpg!

You can check it out here - http://www.fuelly.com/driver/thehomeofdob/75

Mr Benevolent

thehomeofDob wrote: »

I actually tried this the other week. I always drive brim to brim, and always keep a record of miles covered for each tank. I track it on Fuelly.com.

Anyway, I decided to drive like an old man for a full tank and see what I could get out of it. The car is a 2Ltr Rover 75 Diesel CDT (115bhp). Normally I would average about 45mpg, and that's my average since I got the car. With a very light foot and a reduced speed of about 10% under the speed limit on motorways and exactly the speed limit on all other roads I got a whopping 700miles (1130km's) out of 57litres of fuel. 55mpg!

Auto or manual?

thehomeofDob

Confab wrote: »

Auto or manual?

Manual.

Also good to note that my tyres are just within the legal limit of tread., they're booked for a change on pay day.

Leadership

I have a 03 MG ZR 1.8 and I track mine using an iphone app. With a (very) heavy right foot I get 32-35 mpg and when using smart driving I get 40-43 MPG.

rickyjb

I hate this thread with all it's talk of good fuel economy, a good day for me is 9-9.5 L/100km for motorway driving (29-31 mpg) and I'm regularly up around 11 L/100km (25 mpg). Ah well at least petrol is cheap...:)

racso1975

Well finished the heavy dont experiment got 972kms. There was 5 litres left in the tank so filled her with 65 litres. Roll on stage 2 of mind numbing slowness

Stealthirl

rickyjb wrote: »

I hate this thread with all it's talk of good fuel economy, a good day for me is 9-9.5 L/100km for motorway driving (29-31 mpg) and I'm regularly up around 11 L/100km (25 mpg). Ah well at least petrol is cheap...:)

thats good in my book

my avrage fuel consumption
( 16.24 MPG) ( 5.75 Km per litre)( 17.4 litre per 100Km)
Averaging 38.9 cent per mile

So 12K miles would cost €4,670.40

my best was

( 24.68 MPG) ( 8.73 Km per litre)( 11.45 litre per 100Km)
Averaging 25.61 cent per mile

So 12K miles would cost €3,073.20

vectra

I think I may as well scrap this week.:p

Met a buddy with an OPC Zafira this morning and ...!!
well you can guess the rest

Roll on next week

vectra

Week ending 21st Jan 2011
I used 45.25 L of Diesel to cover 712 Kms
Driving Style : Normal
Climate Control @ Auto
Giving me an average of 44.75 MPG

Week Ending 28th Jan 2011
I used 37.47 to cover 694 Kms
Driving Style : Conservatively
Climate control @ Auto
Giving me and Average of 57.20 MPG


Happy with that test
I still think there is better to come

celticbest

vectra wrote: »

I still think there is better to come

I know it has been a while since you last posted but I was wondering has your fuel consumption changed since you last posted ?

vectra

celticbest wrote: »

I know it has been a while since you last posted but I was wondering has your fuel consumption changed since you last posted ?

Yes,
I got bored tooting around so it went back down to mid 40's :P

Since Wednesday I'm staying below 3000rpm and only using gentle acceleration to that, just to see will it make a noticeable improvement on 19mpg. There is a hill just before work that generally I would tear up, crawling up it at 30mph is very very difficult. Will do it until next Friday, then brim it again and see is there a noticeable difference.

EPM

vectra wrote: »

Week ending 21st Jan 2011
I used 45.25 L of Diesel to cover 712 Kms
Driving Style : Normal
Climate Control @ Auto
Giving me an average of 44.75 MPG

Week Ending 28th Jan 2011
I used 37.47 to cover 694 Kms
Driving Style : Conservatively
Climate control @ Auto
Giving me and Average of 57.20 MPG


Happy with that test
I still think there is better to come

Vectra, donyou find temperature makes a big difference to the vRS? Mine is varying from 45-50 on the same cork to Clonmel run. No difference in driving and cruise on all the way. Leave early enough to avoid all traffic completely. Can't understand it. These are trip figures as I haven't had a chance to do proper measurements yet but unless the computers got a mind of its own they should be ok bar being optimistic. Over 5k km and don't even have the thing a month.

MrThrifty

FYI, I find that driving light footed and a 10mph lower max speed gives a 20-25% improvement in mpg but requires a 100% increase in driver patience levels. Nothing worst than feeling like that fecker in front of someone who's driving like an old granny...

mickdw

Ive been driving a 1.3 diesel new astra for the last few day (Hire car). Its a disaster, full pedal at all times just to get anywhere. Its managing just 40 mpg and is very slow. These smaller engines are a complete joke. A reasonable 2.0 diesel in that car would return much better figures.

vectra

EPM wrote: »

Vectra, donyou find temperature makes a big difference to the vRS? Mine is varying from 45-50 on the same cork to Clonmel run. No difference in driving and cruise on all the way. Leave early enough to avoid all traffic completely. Can't understand it. These are trip figures as I haven't had a chance to do proper measurements yet but unless the computers got a mind of its own they should be ok bar being optimistic. Over 5k km and don't even have the thing a month.

I havent really noticed any difference since I bought it..
Two things certainly affect the MPG

One being the obvious heavy/light foot driving style

the other i only noticed this week
In heavy rain my computer reading which is usually at around 6.1~6.3/100

Suddenly was reading 7.4/100
even backed off the throttle a bit but didn't improve anything
Watch for this next time it raining
I use the average 1 reading

Mr Benevolent

vectra wrote: »

the other i only noticed this week
In heavy rain my computer reading which is usually at around 6.1~6.3/100

Suddenly was reading 7.4/100
even backed off the throttle a bit but didn't improve anything
Watch for this next time it raining
I use the average 1 reading

It's possible that the ECU noticed the engine cooling down (rain through the rad) and injected more fuel to compensate. Just a theory, nothing more.

Confab

Confab wrote: »

It's possible that the ECU noticed the engine cooling down (rain through the rad) and injected more fuel to compensate. Just a theory, nothing more.

Interesting, the stat would prevent the engine cooling though by closing as required

BostonB

mickdw wrote: »

Ive been driving a 1.3 diesel new astra for the last few day (Hire car). Its a disaster, full pedal at all times just to get anywhere. Its managing just 40 mpg and is very slow. These smaller engines are a complete joke. A reasonable 2.0 diesel in that car would return much better figures.

Putting the foot top the floor is the wrong way to drive it.

Someone in the family has a 1.3CDTI Astra, older one but I assume its the same engine. Its has narrow power band in the middle. You want stay in the middle of the rev range, not either end of it. So you end up changing gears a lot in it. But they get decent economy out of it. It wouldn't be best suited for busy city traffic, or if you have a heavy right foot or used to something with a lot of torque. But away from that its perky enough once you're in the power band. Out of the band, its slow.

RoverJames

RoverJames wrote: »

Since Wednesday I'm staying below 3000rpm and only using gentle acceleration to that, just to see will it make a noticeable improvement on 19mpg. There is a hill just before work that generally I would tear up, crawling up it at 30mph is very very difficult. Will do it until next Friday, then brim it again and see is there a noticeable difference.

Sweet Jesus this is proving quite difficult.

vectra

RoverJames wrote: »

Sweet Jesus this is proving quite difficult.

LOL
Thats why I am back down to mid 40's
Wrecked my nerves

vectra

Well lads. Back in economy mode again thanks to the price of fuel.. Let see how It goes this time.. Looking good so far. I have seen 5.1/100 yesterday on the display

vectra

OK,
Filled her up there now.


41.29 L for 711 Kms

Approx average of 48.86 MPG

Not too shabby I guess.

Not sure if continued driving in this fashion would my DPF any good