My December 2013 supplied 1.2 TSI SE has been a disappointment in regard to fuel consumption - the overall average (2) - has shown low 30's at best.

 

Suddenly this has now started showing a figure in the high 30's (sometimes low 40's) - my driving has not altered, and several factors may be responsible for this welcome mpg increase.

1 - The ambient temperature has increased

2 - Mileage has now reached 1500 (still low I know)

3 - I buy 95 ron fuel - but bought my latest from a different source.

 

Has anyone had the same experience?

although i drive a 2L tdi vRS i have noticed my mpg has increased greatly during the last few days... i reckon its the increased ambient temperature going from 4-8C to 15-18C (as shown on my cars thermometer) hopefully this weather will stay!

The most obvious thing is that your car is sitting more often with the coolant and oil not so cold at start up.

 

So its maybe not as much as 10 Degrees hotter, but it does take less time/distance to get the engine normal and efficient operating temperatures.

So that saves fuel.

 

And a car run in or running in might be improving anyway.

 

If you have not adjusted the tyre pressures from 1500 miles ago and it was colder then, check what the pressures are at now in this weather (ambient Temperature.)

 

March and its the End of Winter Diesel and Winter Spec Petrol being delivered to Filling Stations.

In Scotland it is still leaving the Depots, no idea about down south if already stopped .

Temperature I'm sure helps. The best mpg I've ever had from my car was on a warm evening last summer at about 22 degrees.

The MPG should keep getting better as the engine loosens up. With my vRS it was literally getting slightly better each week. Try using 98/99ron fuel, see if you think that makes any difference. And like someone else said, check the tyre pressures too. I think that's something so simple which can make a difference that a lot of drivers around the country just never both to check! Enjoy the car!

I see people's mpg is improving! Mine is as well, having gone from low 30's to low to mid 40's! I drive a CAVE vRS!

I thought at cooler temps a turbocharged/supercharged engine was meant to be more efficient aka High Volumetric Cylinder Filling! Hence the need for an intercooler?! Oh well not a complaint!

Your not the only one mate. I thought when the engine was up to temp, it would be most efficient when pulling in cold air.

Obviously not, some how.

Anybody know why? Haha.

The twincharger is certainly most economic when up to Normal operating temperature and the Air Intake from Ambient Temperature still below 12*oC,

(6-12 *oC ambient seems pretty good dependent on what tyres are on the car)

and thats from paying attention for 3 winters and years of Twincharger Driving, so 38,000 miles +

in different vRS on pretty much the same routes, as i have been doing for 30 years in a variety of vehicles.

 

So if its about 0 - 2*oC it will maybe take the Oil near 20 miles to get to above 80*0C, if driving easy,

say the cold roads are not dead dry, That is not Economic for the first 20 miles.

and it might not get near 88-90*oC oil temp

But once you are at temp the cool air means the engine does not require to work to cool the engine (oil/coolant) & once you get to really hot days. as well as fans cooling the engine, it can still suffer heat sink.

(behind the battery on a day above 23*oC and that area can measure above 40*oc while driving and when you stop and there is sun on the bonnet the temp can get above 50*oC, that a hot air box when you start the engine again

The best effect of efficient cool air  intake can probably be noticed best to about 12*oC.

 

I have had really good MPG 2 springs ago in the Heat Wave we had in March for a week temps in the high 20's, Then on the 1st April the Temp dropped 20 Degrees overnight, and the MPG was amazing the next few days,

i was still using the Winter spec Momentum.

but i was up in the Scottish hills in lovely fresh air on the hot days, and smooth roads, and still on

Winter spec Tesco Momentum 99

On 100-102 ron fuel in cool weather things can be even better.

Winter spec petrol on Mainland Europe can give amazing economy.

 

http://www.briskoda.net/forums/topic/261562-450-miles-in-a-vrs-45-mpg

In contrast, in yesterday's pea-soup day, I made a 90 mile odd round trip.

 

Usually, I get 49 mpg average in the Monte - driving style, type of journeys etc etc.  I'm happy with that.

 

Yesterday, I was up to 55 mpg on the average, but also backed up with the "distance remaining" screen.  It climbed, all the way to the destination!!

 

I drove a lot slower than I would have, because of the fog and because of the other idiots that use the road in the fog (NO lights?  Really? 25 mph?? Really?), so an hour's journey took 90 minutes.

 

On the way back, I was not hindered by the fog, or by sloth drivers, so wasn't hanging about.  Even so, by the end of the journey, 55 mpg average.  Distance remaining was at 460 miles, having covered 135.  Not the most scientific, and not a full tank, but I get about 480-495 miles a tank.  These figures predict me getting over 550 (I'll allow it to settle).

 

I would have thought cooler temperatures make it more efficient, developing more power at usual revs, but maybe it wasn't just that, maybe it was the enforced gentler run out and steady speed run back.

Cooler air can help improve mpg and power with normally aspirated engines, once up to temperature. In normal road driving Turbo charged engines are not affected as much by cooler air. As many of you will know, the main reason normally aspirated engines improve is because cooler air is more dense often with a little moisture in it. This improves the amount of fuel air in the cylinder upon induction and the moisture helps improve the combustion to give more power. Since the turbo on the TSI engines is cramming air into the cylinder at high pressure anyway, cooler air doesn't make much difference to power or mpg. Summer fuel helps lots too.

With a TSI that is Twincharged (Supercharged & Turbo Charged)

you can be at the UK NSL and there is no Turbo being used.

That is really what the VAG Experiment is all about with them, getting power on demand yet still have them economical  where required.

As usual VAG have paying customers doing the real world testing, and now they move on to 

COD/ACT, their next Big Thing,

and the Experiment is just that, some customers have good engines and a small number get lemons.

(Ford do Ecoboost, & Volvo are going to run with Twincharging but done properly)

 

I find after quite a few years of Winter Spec Petrol that it is better than the Spring & Summer Spec.

When we first went Unleaded in the UK, and the first Super Unleaded, we noticed differences as we were tuning engines for performance.

 

Its why we used to buy it before the end of the winter & store to go Sprinting & 1/4 mile during the summer.

Thats on Engines that benefit from it.

'Winter Spec Petrol' with a ticky more Ethanol is rather different from Winter Diesel and its performance or economy.

 

I am running a APR Map and have the choice of switchable between the Octanes being used, available with it,

so can easily change between.

Easy to compare if i wanted, but just now am running 99 Momentum Winter Spec.

I will try 102 ron once the Station i use stops getting the Winter Spec Momentum in.

But will go on a few Tanks of the Spring/Summer Spec first.

 

http://www.tescopfs.com/momentum99/specifications

http://www.tescopfs.com/our-fuel/testing_results

** I wonder if we will ever see Royal Dutch Shell publish test results on their fuels**

 

Hiperflo 250

http://vitalequipment.co.uk/Racing_Fuel/carless-hiperflo-racing-fuels

Yep summer fuel I think as I'm getting 69mpg over a 30 mile trip

Do you mean now (March) in Wales or South of the UK & Diesel?

 

What were you getting in the way of MPG, Nov, Dec, Jan & Feb?

High 50's to low 60's but knocking seventy now , warmer temps and the winter stuff being replaced with the summer stuff diesel

I've got a 11 plate fabia vrs and do about 150 miles plus a week and go over the Peak District to work. The best mpg I ve got is 49.2 I was that shocked that it reached the figure I took a picture quickly this was 9 weeks ago in the winter time.