Real life mpg petrrol and diesel

[rcopus]

36.9 in town for the diesel, don't believe it!
I know it was a different car and engine but my 2.0 TDI 143 Ibiza did a hell of a lot better than 36.9 around town. In fact I don't ever recall seeing 36.9 showing unless I'd just switched the engine on cold and moved about half a mile!

Could it be that these figures are poor because they're based on engines that haven't been run-in yet? I managed just shy of 19,000 miles in my Ibiza that I had from new for 15 months.

 

[gaffer1986]

That's true, although I didn't really notice an economy difference between my engine being new and now (car is a 1.6 TDI with 63,000 miles on the clock). My average is 42 mpg over the last 45,000 miles since I've had fuelly, economy going into the 30s round town is not uncommon for me. I am talking about bad traffic stop start town driving.

How was the 143 Ibiza for economy? I wanted a diesel FR but when I bought mine it was yet to go on sale so I got bored waiting and went for the 1.6 TDI, it was a real step down in performance compared to my old 1.9 TDI 130 Ibiza.

 

[DeanC]

Petrols have come a long way now lots are direct injected, turbo'd for low down torque, have start stop etc. But this mainly helps mixed driving. You will still always see at least 20-30% improvement on a warm run just because it's a more efficient way of powering a car and diesels have come on a long way too. There is no way at speed on a motorway a 2.0tdi and 1.8tsi would be within 15mpg of each other.

Although official combined values are meaningless in the real world they are perfect for comparisons and its 20mpg (47 and 67) between the 1.8 tsi and 184 tdi.

On another note, has anyone noticed the 184 is now 112gm co2 band c. Mine is registered 109 and band B

 

[gaffer1986]

Maybe What Cars True MPG is as reliable as the official combined figures? They did that with the Ibiza FR when it first came out, was 119g co2 and went up to 123g co2 a couple of months after release. I think there is something dodgy about the way SEAT test there cars and they get asked to retest again.

 

[DeanC]

Who cares how, saves me money on company car tax

Im not sure on the methodology behind the what car numbers, looks a bit suspect and prone to errors. In my experience since they changed the official test like 5 or 6 years ago you can get the combined figure on a warm engine at 65mph in top gear.

My real life combined is more like low 50s.

 

[Fred99]

see the results between petrol, diesel and hybrid.

If this was common knowledge, I reckon there would be less diesels on the road.

I think you could be right.

When I bought my Mk 1 diesel Leon it was a no brainier ( to be fair at that time in Spain diesel was 20% cheaper). Now it's not so simple. When I decided to get a new Leon I first thought of the 150PS diesel but having researched it a little more and discovered the DPF issue and also had a test drive and discovered that the petrol engines are just as torquey as the diesels I went for the petrol 1.4 TSI.

Just looking at the costs of higher consumption vs higher price it worked out that it would take me 14 years to break even with the diesel option. OK I only do about 5000 miles a year now and that obviously isn't typical.

I note that some members when comparing the costs assume that a diesel will have a higher residual value - that's OK in theory at the moment but if diesels become unfashionable in the next three years that could turn on its head!

It's early days but on a 60 mile motorway run on cruise control (no hold ups on Spanish motorways!) at 75mph indicated I was getting 46mpg on the display. Overall so far it is marginally more thirsty than the old Mk 1 diesel but much more fun to drive.

 

[gaffer1986]

I agree, used car buyers generally do less miles and therefore the depreciation percentage is usually more on a diesel than a petrol. Also I test drove the 1.4 TSI and 2.0 TDI 184 and preferred the petrol, it didn't feel much slower at all. Also I only got 44 mpg from the diesel and 39.9 from the petrol. Taking into account the petrol was £40 a month cheaper on a pcp it had to win. Although I was very impressed with how refined the 184 was, most petrol sounding diesel I have ever driven, I enjoyed both. Must say I didn't notice the difference in suspension, probably because I don't drive fast enough.

Sent from my HTC One S using Tapatalk

 

[rcopus]

How was the 143 Ibiza for economy? I wanted a diesel FR but when I bought mine it was yet to go on sale so I got bored waiting and went for the 1.6 TDI, it was a real step down in performance compared to my old 1.9 TDI 130 Ibiza.

I thought it was very good, okay I never used fuelly, but if the car was 10% out it was still good.
I'd get this from it:
40-50 around town cold
45-55 around town warm
55-60 on motorway doing illegal speeds :roll eyes:
60-65 doing 70 MPH
65-75 doing 55-60 MPH

And to continue the theme of people posting all-time bests, 78.9 mpg

Gaffer some of these figures I've given you are quite conservative too. I claim mileage from my employer and because I'm lazy I used to take pictures of the odometer to enter them into the system later. Looking at some old pictures on my phone I always used to get great MPG. Hope I haven't made a mistake in the 1.4 TSI I have sat on the drive

 

[gaffer1986]

I'd be very please with that mpg, in fairness to my 1.6, is it always subjected to the worst you can throw at it for fuel economy (busy town and learners driving it). However, when I'm driving and there isn't much traffic, 50mpg + is very achievable when warm round town, however it struggles to get more than 45 mpg at 70 mph.

It will be interesting to see what your 1.4 TSI gets, it's a great torquey engine and in my opinion worth a slight drop in mpg.

 

[DeanC]

Its worth noting the 1.6tdi is last gen. I had a 1.6tdi mk3 5 door courtesy car when mine was in for rattles and I got 15mpg less than my 184 on my commute and I drove like a saint as I pre-filled it at 55mpg (I did 52mpg).

 

[gaffer1986]

ps. I have achieved low 70s on a couple of occasions, but the conditions where perfect for it and I can only recall 3 occasions in nearly 4 years. The first occasion was when I drove it home from the dealers (brand new with less than 10 miles on the clock) which included a long stint of 50 mph on the M25. I was absolutely elated that I had such economical car, the smile soon disappeared as 42 became the norm.

Hence why I believe newer cars are not less economical. If they are it much be incredibly marginal.

 

[gaffer1986]

Its worth noting the 1.6tdi is last gen. I had a 1.6tdi mk3 5 door courtesy car when mine was in for rattles and I got 15mpg less than my 184 on my commute and I drove like a saint as I pre-filled it at 55mpg (I did 52mpg).

That's true, the EA288 engines are better. I think the Mk3 Leon has the old 1.6 TDI, the EA288 1.6 is only in the ecomotive which has just gone on sale with 110PS

 

[gaffer1986]

However the official economy of your 184 leon is the same as my 1.6 TDI Ibiza, which is strange if you got more economy out of it.

 

[rcopus]

It will be interesting to see what your 1.4 TSI gets, it's a great torquey engine and in my opinion worth a slight drop in mpg.

At the moment on cold-start 10 mile town round trip, high 30's... (in 'Normal' driving mode)

I'm not going to start paying too much attention until its done 1000 miles, because I may start driving it differently once its run-in. I may have to change my driving style altogether as I used to drive the TDI to get the the legal speed in the shortest time possible pretty much all the time, ahem! With the TDI it never seemed to matter if I rev'd the hell out of it, economy was pretty much the same.

 

[DeanC]

I probably don't around town etc. My commute is 100 motorway miles though so I benefit from crusing around steady on 380nm torque hardly working it. This is where any 1.6 diesel will suffer compared to a 2.0.

 

[gaffer1986]

I probably don't around town etc. My commute is 100 motorway miles though so I benefit from crusing around steady on 380nm torque hardly working it. This is where any 1.6 diesel will suffer compared to a 2.0.

I've never understood this about engines, because if it takes 25-35 horse power to achieve 70 mph, I would have thought the smaller engine with less gas to compress in the 4 stroke cycle would be more efficient.

The 1.6 would be using more of it's potential to achieve the same power but in theory it should take no more fuel to achieve the power needed to go 70 mph.

But you are right, I have noticed the 2.0 TDI is better at 70 mph.

 

[rcopus]

Isn't that because the 2.0 would be doing less RPM than the 1.6 to do the same speed?
The amount of extra diesel to fill the larger 400cc of the 2.0 is probably not that much, whereas the extra fuel required to turn the 1.6 over more frequently could be considerable...

Just my 2p!

 

[gaffer1986]

Oh yeah, RPM, forgot about that.

 

[DeanC]

Plus a diesel runs lean. You cant think of it as it always filling a 2.0 over a 1.6 because it uses what it needs. It's load that really impacts mpg - if you do a constant speed and switch between 4th, 5th and 6th you will not notice much difference. There will be a slight variance with varying efficiencies at different rpms and interal friction etc but as the load is the same the figures remain similar. Like going up a hill results in the same rpm but a higher load and therefore more fuel.

Bigger engines don't work as hard at any given load - you can make the same amount of fuel do more work.

 

[Fraczish]

^^^ a certain test on top gear involving a Toyota Prius Vs a BMW M3 springs to mind...