1.6 Tdci Fuel Economy

[catch]

again giving the petrol 1.6 99bhp comparison:-

Just done 547 miles Maidstone in Kent from North Yorkshire, down one day back the next. 90 mile cross country to get on the A1 at Boston Spa. A14, M11, North Circular[had Sat Nav set to avoid Tolls] with a stop off at relatives in Strood Rochester, then onto Maidstone. Came back M2/A2 M25 Dartford Tunnel [£1.50 Toll] M11/A1 etc. Four adults up, and doing the speed limits or a tad over. Computer recorded 39.40 mpg, but brim test proved 37.55mpg. The comp also recorded average speed at 49mph.

Comp was 2.64% over estimating mpg on a previous 1000+ holiday, and on this 500+ journey it was over estimating mpg by 4.70% Funny that, as I would have thought any over read percentage would be the same, not varying the percentage out by nigh on 100% between the two

Now just as a time comparison regards going M11, North Circular, through No Toll Tunnel, as against M11, M25, Toll Tunnel:- I know exactly how long the M11 Services to Strood journey took via the North Circular. As I had a phone call just as we were about to leave the Services, asking how long we would be. Sat Nav said an hour arriving at 11.50am and we did it in 59 minutes, 54.8 miles. With no hold ups at all other than traffic lights. Just looking now on Google Maps journey planner going the Toll Route it has it down as taking 51 minutes 46.4 miles. When we came back that way traffic was slowed due to road works so I reckon in real time there would not have been 5 minutes difference in both routes.

[jig]

I have the same car and find running it around 1800-2000rpm around town gives the best MPG dont run the motor out of the turbo boost zone. I do mostly A-B Road with MWays once a week and get 50mpg on average (calculated).

This seems to be suggested by a few people,to keep the turbo on boost for economy. If you're boosting then you are forcing more air in and in turn more fuel so how is this economical?

[true grit]

I have a 2010 Titanium 1.6 TDCI 109 DPF.

Trouble is the fuel economy Im getting on the trip doesnt seem quite right, at best I can get 46-47mpg(driving like a snail) and everyday driving keeping up with normal traffic its like 38mpg.

I do admit most of this driving is around town 30-50 mph but surely it should be atleast 50mpg? I have checked all the tyre pressures and they are ok, its currently done 1700miles and has loosened up quite alot but the economy if anything has got slightly worse since new.

I hear the ford trips over read by about 5mpg if thats the case then something is definatley wrong, does anyone else experience similar problems with the 1.6 TDCI and can anyone give me their current MPG so I can compare?

Cheers

I have a 56 plate Focus Zetec estate I work shifts so its used in all weathers and times of the day I live in a busy town not a city. My Focus has never dipped below 50 mpg around here and on runs I can get 58-62mpg at normal motor way driving and once on a long run I got 70 mpg (which I worked out to make sure ).

[Preload]

This seems to be suggested by a few people,to keep the turbo on boost for economy. If you're boosting then you are forcing more air in and in turn more fuel so how is this economical?

Forcing in more air not necessarily more fuel.

Turbo engines are designed to take the high pressure turbo's can make but running outside of the boost area the compression is very low and produces a lot less power so to move the car it wastes fuel.

Most turbo engines are designed for power but they can be used for economy as well.

[mross]

I agree with Jig, actually if more air is forced into the combustion chamber (via a turbo charger)then more fuel is also added to compensate otherwise the engine would be running lean and not very efficient at all, the cars ECU pumps in the exact right amount of fuel for the amount of air being pushed in by a turbo, numerous sensors are transmitting data to the cars brain (ECU) all the time. The ECU is constantly adjusting the fuel and air mixture depending on the environment and driving style. Turbo units on any vehicle are designed to give 30% more power and increased torque as a standard figure, but using the turbo in the sweet spot rev range 1900 to 2700 rpm will increase your fuel consumption depending on how heavy your right boot is of course. There is no such thing as wasted fuel either as every particle burnt contributes to the polar movement of inertia, unless it is un-burnt fuel then there is an apparent problem in the combustion process.

ps: This post has opened up a can of worms lol.

[jig]

Having owned a few turbo charged Saabs,they show economy dropping with revs and boost,not conclusive

[Preload]

The amount of power which an engine can produce is limited by how much fuel it can burn, and the amount of fuel it can burn is limited by the amount of oxygen in the cylinder. The amount of oxygen in the cylinder is limited by the amount of air in the cylinder. So, if more power is wanted then more air is needed, how do we achieve this? Well a large engine has more air, so it can produce more power, or compress the air before it gets to the cylinders.

The key to fuel efficiency is to squeeze as much energy as possible out of a given amount of fuel by burning it as completely as possible. Diesel fuel itself has the potential to produce more power than a like quantity of petrol. Furthermore, high compression ratios help diesels to burn their fuel more completely than petrol engines. And because diesels always intake a full charge of air while varying the amount of fuel, the air-fuel mixture tends to be a very lean mixture at lower power outputs, which helps burn the fuel more completely.

[Kira000]

I've had my brand new 1.6 tdci titanium for just over a month - 900miles on the dial now. I have been a bit disappointed in the fuel economy compared to my previous fiesta- 08/08 1.6tdci zetec climate, with which i consistently got 60-67mpg mainly on commuting on roads between 20-50mph. With my new fiesta on the same roads, i am currently getting 57.8- 58.4mpg. As i said, a little disappointed, but reading some other experiences, it seems i'm not doing too bad!

I am paying more attention to braking and accelerating more gently now, to try and improve the MPG but i was never that heavy on them to start with. I also drive in 5th as early and often as possible, which seems to help- i've only had the gear change arrow appear once, and that was test accelerating when i first got the car to get a feel for it.

I will be interested to see what happens over the seasons, as i found in my old 1.6 tdci, the MPG dropped in winter, to around 56mpg, comapred to the 67mpg i got in the summer. Curious!

[SteveTDCI]

Really is a strange one this, my line of thought is that higher mileage vehicles with this particular engine will infact squeeze more mpg than those that are less ran in but it would be interesting to take a peak at Peugeot/Citroen forums and see what those drivers are saying about their 110 HDI units.

Ill take a look and report back on my findings :P

[Wibbly]

I've had my brand new 1.6 tdci titanium for just over a month - 900miles on the dial now. I have been a bit disappointed in the fuel economy compared to my previous fiesta- 08/08 1.6tdci zetec climate, with which i consistently got 60-67mpg mainly on commuting on roads between 20-50mph. With my new fiesta on the same roads, i am currently getting 57.8- 58.4mpg. As i said, a little disappointed, but reading some other experiences, it seems i'm not doing too bad!

900 miles isn't much. I'd expect the engine to still be tight, impacting fuel consumption. See what happens after 2.5k, 5k, even 10k miles.

[SteveTDCI]

Well after 5000 miles Im still not seeing an improvement on economy. I've bitten the bullet and invested in a RoverRon tuning box to see if I can get this figure of 42-46 mpg any higher. It should be with me in a few days and once fitted(going to be a pain) ill be sure to advise of the results.

[SteveTDCI]

Well I went ahead and fitted the box today, was an absolute pain. Trust me people are not exaggerating just how frustrating it is fitting a tuning box to one of these engines. In the end though it was completely worth it.

Mid range was always good at standard setup but now from 40 to 70 its astonishingly quick, even after spending 2 hours blasting round the local country lanes I still averaged 44mpg something that would have been considerably lower before. As a test I did my local commute route and averaged 57.8mpg which is the highest I have every achieved on that route in this car(all busy town roads).

In this respect its obvious that If you drive correctly when using a box they do what they say on the tin.

Word of warning though, the many guides out their that suggest you to look for the RED common rail plug are now incorrect for the 2010 onwards 1.6 TDCI engine. The plugs are now BLACK which I can only presume is Ford/PSA's way of hiding it.

[toyer00]

Ive just brought a 2005 1.6 TDCI mk2 focus saloon with just under 50k on the clock. I have got about 40 MPG around town which is amazing compared to my old Golf GTI 1.8T. My concern is yesterday I drove to London from Birmingham all motorway I had the cruise control on doing 80 there and the same back at 2 in the morning so hardly had to break or stop. I was only getting 45 MPG even after i reset the trip. Now I dont know if the cruise control affected this has this is my first car with this feature. Am I being naive in believing the official figures or missing something obvious. The only other thing I was thinking is it may have been sat for a while at the garage or maybe try some fuel additives.

Any help will be welcome

[Wibbly]

Ive just brought a 2005 1.6 TDCI mk2 focus saloon with just under 50k on the clock. I have got about 40 MPG around town which is amazing compared to my old Golf GTI 1.8T. My concern is yesterday I drove to London from Birmingham all motorway I had the cruise control on doing 80 there and the same back at 2 in the morning so hardly had to break or stop. I was only getting 45 MPG even after i reset the trip. Now I dont know if the cruise control affected this has this is my first car with this feature. Am I being naive in believing the official figures or missing something obvious. The only other thing I was thinking is it may have been sat for a while at the garage or maybe try some fuel additives.

Any help will be welcome

What makes you think should be achieving any better at 80mph?

[Wibbly]

Well I went ahead and fitted the box today, was an absolute pain. Trust me people are not exaggerating just how frustrating it is fitting a tuning box to one of these engines. In the end though it was completely worth it.

Mid range was always good at standard setup but now from 40 to 70 its astonishingly quick, even after spending 2 hours blasting round the local country lanes I still averaged 44mpg something that would have been considerably lower before. As a test I did my local commute route and averaged 57.8mpg which is the highest I have every achieved on that route in this car(all busy town roads).

In this respect its obvious that If you drive correctly when using a box they do what they say on the tin.

Word of warning though, the many guides out their that suggest you to look for the RED common rail plug are now incorrect for the 2010 onwards 1.6 TDCI engine. The plugs are now BLACK which I can only presume is Ford/PSA's way of hiding it.

Is there a trade-off using these kind of tuning boxes (other than their initial cost)? Seems odd that manufacturers wouldn't do this as standard to get class leading performance/enconomy... Why wouldn't they?

[toyer00]

What makes you think should be achieving any better at 80mph?

Surely at 80mph doing 2500 revs I should be getting better MPG then town driving in my old golf i got 28 town then 40 at 80 on the motorway. I was at least expecting 50-60 MPG at 80 is this wrong of me?

[Wibbly]

Surely at 80mph doing 2500 revs I should be getting better MPG then town driving in my old golf i got 28 town then 40 at 80 on the motorway. I was at least expecting 50-60 MPG at 80 is this wrong of me?

I think a lot is down to driving style and how you use the available power. Also Diesels are supposed to be relatively more efficient at narrow throttle openings compared with petrol, so blasting down the motorway at 80 (and overcoming all the wind resistance at that speed) isn't going to get you amazing economy and possibly not much better than a petrol equivalent. Increasing speed a little increases wind resistance disproportionately. I don't think the revs has much to do with - think of gas guzzling slow revving American V8's! Low revs just means it's not a buzz box.

For what it's worth I had a 1.6 petrol Focus as a loan car for a day. Amazing how gutless it felt and how I seemed to have to rev it all the time. Gotta love diesels in this respect. Just have to be going fast enough not to hear/feel the diesel's engine's 'unrefined' noise!

I've done 36000 in my 1.6 tdci and have averaged about 57mpg. I drive 'gently'.

[toyer00]

I think a lot is down to driving style and how you use the available power. Also Diesels are supposed to be relatively more efficient at narrow throttle openings compared with petrol, so blasting down the motorway at 80 (and overcoming all the wind resistance at that speed) isn't going to get you amazing economy and possibly not much better than a petrol equivalent. Increasing speed a little increases wind resistance disproportionately. I don't think the revs has much to do with - think of gas guzzling slow revving American V8's! Low revs just means it's not a buzz box.

For what it's worth I had a 1.6 petrol Focus as a loan car for a day. Amazing how gutless it felt and how I seemed to have to rev it all the time. Gotta love diesels in this respect. Just have to be going fast enough not to hear/feel the diesel's engine's 'unrefined' noise!

I've done 36000 in my 1.6 tdci and have averaged about 57mpg. I drive 'gently'.

Thank you Wibbly for your feedback like I said i just had the cruise control set to 80 on a clear motorway but 45 is still a lot better then my old golf around town. So far I love the focus and its a GHIA so it has all the mod cons. Ill just try driving it a little slower next time see what I get.

Cheers

[Wibbly]

I find economy (according to the avg mpg on the dash) gets a LOT better when I'm stuck in slow speed traffic on the motorway, even if it's a bit stop-start, and best if it just stays moving and I don't have to brake too much. In that situation I'm forced to 65mph or less typically. Also get in the habit of using the 'slow' lane so long a people are making reasonable progress. If you do the maths, it won't actually increase your journey time as much as you think it will - and five or ten minutes here or there usually doesn't get noticed too much on a longer trip.

From http://en.wikipedia.org/wiki/Fuel_economy_in_automobiles

"The power to overcome air resistance increases roughly with the cube of the speed, and thus the energy required per unit distance is roughly proportional to the square of speed. Because air resistance increases so rapidly with speed, above about 30 mph (48 km/h), it becomes a dominant limiting factor. Driving at 45 rather than 65 mph (72 rather than 105 km/h) requires about one-third the power to overcome wind resistance, or about one-half the energy per unit distance, and much greater fuel economy can be achieved. Increasing speed to 90 mph (145 km/h) from 65 mph (105 km/h) increases the power requirement by 2.6 times, the energy per unit distance by 1.9 times, and decreases fuel economy. In real world vehicles the change in fuel economy is less than the values quoted above due to complicating factors."

Basically, drive a BIT slower and save a LOT of fuel.

Cruise controls aren't the best way of saving fuel either, as popular wisdom is that it's more efficient to let the car slow down when climbing hills... (though maybe it's just better just because you're going more slowly at a more efficient throttle opening)

[catch]

Here are some figures I've achieved, OK it's on a petrol 1.6 but it is relative to your enquiries in that it shows how MPG drops off the harder you push an engine.

Short 6 mile trip on quite motorway, cruising @ 54mph I got 59.50 mpg on the comp.

Country A road 11 miles @ circa 50mph comp showed 57.30 mpg.

209 mile trip all motorway cruising at 70.0 mpg comp showing 41.2 mpg

Skipton to Cornwall and back 881 miles, Motorway cruising at circa 75 mpg comp showed 37.4 mpg

The above figures prove once your start pushing it over the middle fifties mph, economic mpg drops off considerably. Well it does on my 5 speed petrol engine. And I assume the official mpg figures are built around the 56 mph figure because that is more or less the sweet spot for miles per gallon returned

[Barry_]

I just done a 400 round trip in my 1.8 tdci and according to the trip meter i got about 54/55 mpg crusing around 80 (combo of motorway and A road dual carraige ways) Unfortunately i had to go back home after 100 miles (forgot my wallet ) so on way back out again i was more 85/90 and dropped to about 52mpg. Trip back was not rushed as much and overal the mpg stated was 53 mpg.

[Wibbly]

Here are some figures I've achieved, OK it's on a petrol 1.6 but it is relative to your enquiries in that it shows how MPG drops off the harder you push an engine.

Short 6 mile trip on quite motorway, cruising @ 54mph I got 59.50 mpg on the comp.

Country A road 11 miles @ circa 50mph comp showed 57.30 mpg.

209 mile trip all motorway cruising at 70.0 mpg comp showing 41.2 mpg

Skipton to Cornwall and back 881 miles, Motorway cruising at circa 75 mpg comp showed 37.4 mpg

The above figures prove once your start pushing it over the middle fifties mph, economic mpg drops off considerably. Well it does on my 5 speed petrol engine. And I assume the official mpg figures are built around the 56 mph figure because that is more or less the sweet spot for miles per gallon returned

Yeah - main difference with a diesel *should* be better fuel economy than petrol when in equivalent stop start/small throttle openings. One reason why they've remained popular for delivery vans, despite the higher fuel price.

[Wibbly]

Anyone checked the accuracy of their trip MPG meter? I recon mine is less accurate at higher MPGs and adds a 1 or 2 MPG - so optimistic by a few %. I look at averages when brimming the tank.

[Druberry]

I have the 1.6 tdci Zetec s, just done a weekend to lake district from Devon, totalled 900 miles the average overall was 57mpg, not bad as had a head wind coming home and did not hang around. Around town I tend to get 48 mpg. My parents have 1.6 tdci but only do short journeys (3300 miles in 18 months) they get 43mpg. Have a nice day.

[catch]

I have the 1.6 tdci Zetec s, just done a weekend to lake district from Devon, totalled 900 miles the average overall was 57mpg, not bad as had a head wind coming home and did not hang around. Around town I tend to get 48 mpg. My parents have 1.6 tdci but only do short journeys (3300 miles in 18 months) they get 43mpg. Have a nice day.

Those are decent figures there Andy, what kind of average mph cruise speed where you achieving on the motorways when you had an open road in front of you [no holds ups]

Regards your parents drive totals, 3,300 miles in 18 months. I'd be interested to know how old is the car, have they had it from new, and have they had any DPF issues with it.

I ask because Mk2 /2.5 TDCi's fitted with DPF's can have issues if only used for pottering about on short journeys. And lets be fair at 3,300 miles in 18 months it fits the profile. Setting aside for one moment the obvious argument that paying the "Diesel Price Premium" at point of purchase. And the added service costs of maintaining / replacing the DPF, far outweighs any savings they could possibly make in fuels visa vee petrol/diesel.

But it may be the case that your parents have had no issues with the DPF, so making peeps like me doing circa 5 to 6k per annum revisit the buy diesel or petrol option.

By the way Welcome to the forum.