Fuel Consumption...

[vwawudi]

Switched over from winter to summer tyres and I expected a big improvement in fuel consumption. Through the winter, I was getting barely 500miles from a full tank and after swapping tyres, it took a while but the best I've achieved is around 550-570miles.

Took it to the dealer who simply looked at the on-board computer readings and told me every thing was normal. I'm pretty sure I was getting closer to 600miles out of a full tank last year when I first picked up the car.

What gives?

My oil level is less than half (when warmed up) and I wonder can that contribute in any way?

It appears my Pirelli P7s are worn to about 4mm or so, is that another factor?

Thanks for any help folks.

PS: 2.0 TDi SE Exec Saloon Multitronic.

[vwawudi]

Bumpity bump!

[ScottyUK]

Warmer weather means less dense and lower humidity air and hence a smaller explosion in the chamber. Turbo cars have intercoolers to try and cool the air as much as possible but they always feel more alive on a damp cold morning. Maybe that's it?

My 2.0T just gave me the first 30mpg tank of it's life!! It was on a run down to the Goodwood Festival of Speed and despite the 30 mins being stuck in a queue and a bit of fun with a Golf GTi for 5-10 miles it did quite well. ;)

[vwawudi]

I feel the consumption is not as good as it was when I picked up the car in Sept last year. Almost resigned myself to it now.

Can the oil level have anything to do with it? Would a top up be helpful?

[theskyfox]

I'd say 570miles to a tank is about right for a 2.0TDi?? I used to get about that on a 1.9TDi, and that was a front-wheel drive manual. Youre gonna lose some MPG because its auto. Don't forget the A4 is a heavy car too....(relative to small cars). If you want to be really OCD..you could always start driving at 50mph everywhere on the motorway, avoid traffic jams, and drive in your socks barely touching the brakes and accelerator. Take every bit of **** out of the car including any manuals, bottles of water etc...and never drive short journeys.

-Andrew

[vwawudi]

I'd say 570miles to a tank is about right for a 2.0TDi?? I used to get about that on a 1.9TDi, and that was a front-wheel drive manual. Youre gonna lose some MPG because its auto. Don't forget the A4 is a heavy car too....(relative to small cars). If you want to be really OCD..you could always start driving at 50mph everywhere on the motorway, avoid traffic jams, and drive in your socks barely touching the brakes and accelerator. Take every bit of **** out of the car including any manuals, bottles of water etc...and never drive short journeys.

-Andrew

Ha ha! ROFL.

[J_B204]

I've the 170ps quattro and always get over 500 miles on a tank. typically around 570, on long runs (ie motorway at legal speeds) over 620 but that is taking it carefully. this isn't based on the DIS but on the distance between tankfuls.

being a quattro 2.0 170 it is manual so I reckon what you are getting is about right.

[vwawudi]

Thanks guys. I guess I'll have to live with it if it's the norm. It seems I was expecting too much from the 2.0TDi...

[Brycie]

I also have the A6 2.0 TDI SE Saloon but manual & I can get as little as 550 miles to a tank too, so I think it's normal for urban mileage. However last weekend I had a tank of fuel last 680 miles, about 560 miles on motorway at 80mph (so not exactly in economy mode) in good traffic and frequently slowing to 50-60 at busier times, the rest on A roads. Given a proper road test, you'd probably be quite surprised how far it'll get you on a tank.

[theskyfox]

Just an afterthought...vwawudi how many miles has your car got on the clock? If its low milage, the engine may still be tight. Higher milage tend to be looser and give slightly better MPG. Also some of the premium grade fuels can give you a few more miles to the tank (although also remove a few more ££ from your wallet in the process, but if its numbers your after...).

-Andrew

[SunnyBard]

If its low milage, the engine may still be tight.
You'll see from the spritmonitor link in my .sig the fuel economy I'm getting, while I'm not disappointed (I rarely drive purely for economy) I'm hoping it will improve a little, looking at other spritmonitor users with the same model, this chap seems to be doing rather well ...

http://www.spritmonitor.de/en/detail/431903.html
(http://www.spritmonitor.de/en/detail/431903.html)

[Eshrules]

based on a 65l tank, 550 miles = ~38mpg.

you don't say if this is around town or on the m.way - but auto's will always get less than manuals.

are you an ecodriver, or do you use the right foot quite a lot?

Ensure your fluids (including oil) are at the correct levels too.

[Niko]

I have 22K on the clock a little over a year old 170 SLine running 19in tyres. I travel the same 25 mile route to work each day, there and back. When I took delivery of the car I was impressed with the 58, sometimes 61.8 on the DIS when I drew into the car park. Come winter I was getting nowhere near that, lucky to hit 50. I assumed that the car was getting less miles due to age, needing service etc. The fact is as we came into the warmer weather this year the mpg has returned to the same as last spring/summer/autumn, longer between fillups and the DIS returning to over 60 most days when the weather is warm and I get a good run without hold ups. Over 600 miles to a tank is easy in the summer, mixed driving.

[vwawudi]

Thanks guys. I think my mileage is around 23k, registered Dec 09, so about 19months old.

Daily commute is a mix of A-road (2 miles, 50mph), motorway (9 miles of 50 and 60mph) and a final approx 5 miles of 70mph fun on an A-road before a few slow 30-40mph roads to workplace. ~18 miles each way.

Gentle on the throttle, no heavy foot, usually keep revs below 2,000.

My oil level (DIS dipstick) is below half though, asked the dealer if I should bring it in for an oil change and was told it would be a waste of money. Thinking of topping up the oil in case the engine needs it. Would that help?

My DIS has NEVER hit 60mpg, don't think I've ever seen 55mpg in fact...

[Bratty]

I would not get too bogged down on the reduction in "indicated" fuel economy as fuel ecomomy is just simply distance travelled divided by the measured fuel flow, You state that your tyres have worn therefore smaller rolling circumference, therefore MPG will drop slightly over time.

Your winter tyres will also have a different rolling circumference which needs to be taken into account.

Dunk

[SunnyBard]

My oil level (DIS dipstick) is below half though

Dunno if the Audi TDIs are the same, but I used to find that my Honda i-CDTi gave slightly better mpg (and smaller clouds of black smoke, no DPF then) if I kept the oil towards the bottom dipstick mark, rather than the top one.