MPG 1.4TSi

[RW1]

Has anyone else noticced that in the last few weeks, since the weather has warmed up, that their mpg has suddenly increased by about 5mpg ?
I also remember it dropping about 5mpg at the end of last summer.

The change for mine is about 3 mpg. Didn't get a sudden change in the mpg indication but did notice a sudden oil temp change of 3'C to 4'C with a tank of fuel last autumn and it has stayed there until the tank full I've just put in where its jumped back up again.

As Deacon says, its a winter thing generally with longer warm-up periods and therefore more fuel usage. Last old Mk2 Scirocco I had for 16 years showed that up in its mpg chart. The general change being about 6 mpg, but never a step change, just seasonally cyclic.

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I'm looking forward to the cold, dense air and the benefits it offers turbo's... but for now the warm weather will be just fine!

To continue the slight tangents on this thread.... has anyone noticed any significant difference with different fuel types?

The 160PS seems to be at its best around 15'C - 20'C outside air temperature, colder air doesn't appear to improve general driving. The engine is massively overcooled in standard form.

160PS fuels

C.

[Scott_mac]

Thanks - seems the standard fuel debates rage on all fora!

[maisbitt]

Has anyone else noticced that in the last few weeks, since the weather has warmed up, that their mpg has suddenly increased by about 5mpg ?
I aloso remember it dropping about 5mpg at the end of last summer.

It's because the engine gets warmer a lot quicker than in the colder months so improving fuel consumption

It's not just that. In the summer months, the air is more humid - cold winter air has very little moisture in it. With warm and moist air there is a bigger expansion of the combusted gases due to the vapourised water expanding for less fuel. Air has a far higher expansion coefficient when it is saturated with moisture, meaning a bigger combustion effect for less fuel in.

Just this weekend I drove down to Southampton from Newcastle (353 miles) on the way down the temp got up to 27C from a 7C start at 6am. Did a constant indicated 75-80mph on the motorways, and for 1/2 the journey I had the aircon. No traffic at all until the last 20 miles, which took an hour - trip average was 59mpg.

Did exactly the same on the way back, set off same time, and I actually drove a smidge slower (stricter maintenance of 75mph speed) , absolutely no traffic at all, and didn't use the aircon at all, but my trip average was 56mpg. The starting temp was higher on the way back (8C) at 6am, but the temp never got above 17C, and was only as high as 13C for the majority of the trip.

In summary, a much higher ambient temp gave me a 5% increase in economy despite having the aircon on. For the length of my trip, the time taken for the engine to warm up had a pretty irrelevant effect on my trip's consumption, although it can have a large effect on small journeys.

[scooby_doo]

Wow - wasn't expecting to ignite so much good conversation from my request.
Thanks for the info guys - looks as though I'll be getting a good 170+ miles more out of a tank with the roc' - very happy
Dan.

[Seadoo110]

I averaged 28-29mpg from mine in 3500miles

Mainly urban during the week and some longer runs at the weekend.

Even on the motorway I had to be light with the throttle and keep <75 to keep it 40-42 mpg.

I was very disappointed with the mpg, no where near the book figures (more so than any other car i've had) you really have to drive it carefully to get any kind of good mpg from the tsi, which got on my nerves and i switched back to the darkside and got myself a tdi, which I can pretty much surf the torque everywhere and it wont drop below 40mpg, if i wanted to keep the same pace in the tsi I would be alot worse off mpg wise. Yes its not as much fun as working the little tsi before anyone comes in on that one.

Half of my miles were in the winter so may account for a few mpg's though

Out of curiosity is the 1.4 (160) much better in real world mpg to the 2.0 if both are driven for economy?

[ZephyR]

And don't forget that in the winter months you are using your lights, wipers, fan, heated rear window a lot more than in summer - all of which affect to some degree our fuel consumption. On top of that in wet, slippy conditions and darker evenings traffic tends to move a lot slower with more congestion.

[skyblues11]

with this damp air theory, does this means living in a humid, but reasonably warm place brings out the best in the turbo engine?

Irish Republic in the summer perhaps?

[maisbitt]

Skyblues: Yep. You'll see noticeable gains on a hot and humid day, as opposed to living somewhere hot and arid. A litre of air saturated with moisture (high humidity) will expand noticeably more with heat than a litre of dry air with the same amount of heat, to the same pressure.

I demonstrated with my long-winded story before that on an identical journey, with a lower ambient temp, I used noticeably more fuel, despite the use of aircon on the more economical journey.

On a cold day, the air has very little moisture saturation, hence condensation first thing on a morning when the air from the day before cools down and dumps it's moisture.

[Scott_mac]

with this damp air theory, does this means living in a humid, but reasonably warm place brings out the best in the turbo engine?

Irish Republic in the summer perhaps?

Cold, dense air is best for performance with a turbo engine... not so great for fuel economy though!!

[maisbitt]

If it's cold, the fuel will be denser also (very slightly), so you'll use more - another reason why cars are thirstier in the winter.

[rococco]

I have averaged 8.6l/100km (32.5mpg) over 1000kms (engine already bedded in). That's on a roughly 50/50 mix of urban/extra-urban driving with what I imagine to be a fairly typical driving style: smooth and reserved most of the time with some quick bursts.

This appears to be in line with others' reported fuel economy. So why the huge difference from VW's advertised figures (6.3l/100km, 44.8mpg)? Is such a large gap typical of most cars? Did VW test their car in a vacuum? Has anyone managed to approach their figures, even driving especially carefully?

As an aside, I notice a mistake on VW's website where it claims a combined fuel-economy of 5.5l/100kms for the DSG 160bhp instead of 6.3l/100kms. False advertising?

[maisbitt]

Optimistic economy figures is the same throughout the motor industry, based upon lab conditions, not real conditions:-

Rolling road
No wind resistance
No occupants or load of any kind
Minimal electical load from the ancillaries
No hills to climb
No potholes
Speed maintenance not related to road speed limits e.g. 56mph.

Some manufacturers have been known to have been using special low viscosity lubricants and non standard tyres etc.

In the summer, with a measured and intelligent driving style (anticipation of obstacles, not accelerating to a point where you'll inevitably have to brake hard etc) some people will expect to beat the combined figure on a journey that most closely resembles the simulated extra urban route in the tests e.g. mainly cruising at a constant speed, and they may beat it by around 10%, maybe a bit more if they drive like a nun. Beating the extra urban figure is pie in the sky.

[ZephyR]

Yes the "Official mpg" figures are artificial but they do allow you to compare one vehicle against another and see which offers the better mpg.
It will be possible to exceed the official figures by driving carefully, avoiding breaking, stoping etc. But that's because the official mpg test cycle does include braking and acelerating as well as idling for periods (as if at trafffic lights) to simulate a typical urban journey.

[r.gbrown]

I've only had my Scirocco for a week or two and love everything about it. Well, nearly everything.
My MPG is only around 28. I know that the kind of driving I do means MPG will not be great (only 9 miles to work and 9 back, town driving, so not really heated up properly) but I'm not hard on the pedal. At least not till run in! Is 28 or so about right for my kind of use? I've not recorded a long run yet and I'm sure the MPG will be better. Still love my Roc

[happymum67]

Mines a manual and round town lucky to get over 30mpg when cold. 35ish when hot. Done 14000miles

[Seadoo110]

Sounds about right to me (mine was a manual) similar commute distance, I was really disappointed in the mpg overall tbh I went back to the dark side wished I'd just. Got the 2.0 as I don't think that's much worse mpg wise. It'll get better in the summer as the engine takes a while to get up to temp. I just couldn't get over the fact I was getting sub 30 even driving like a saint don't mind so much if your spanking it.

[sciroccorocket]

thats about the same as my R

[RW1]

Averaging 35mpg overall so far @ 13,500 miles. My old Mk2 8v Injection Scirocco 112bhp, averaged 38mpg. My VR6 at 190bhp does 34mpg average overall. So its not bad at all.

32 - 33 mpg knocking about in traffic (5 - 7 mile trips), 42 - 44mpg on the motorway cruise.
Mpg didn't settle down until gone 5,000 miles.

Early miles in urban was 28mpg, motorway was 38mpg.
Booting gives 4.5mpg indicated.

Use Shell V Power.

C.