New car mpg musings

[kalniel]

For those not keeping track of the saga, new car is A3 sportback 1.4 tfsi ultra (ie cylinder on demand).

Since last update I've discovered:

-The ride has softened up noticeably as it beds in/the bushes become more compliant. It's still not as smooth as the old A3, but I'm no longer wanting to swear over potholes.

-There are several interior rattles. Audi did try and sort one of them out, but haven't had much success.

-They did fix a minor leak in the washer fluid system. It's still a pain because it's a tiny reservoir and the xenon jet wash uses tons, but it's better than before.

-It takes far too long to book an appointment with Audi. Nearly a month unless there are cancellations. They're very apologetic about the backlog, and aren't trying to claim it's only this one occasion, but it's been the situation since Christmas. However had I known when I'd bought the car then it'd have been factored into the purchase decision. Hire some more people and get some more courtesy cars!

But onto every car forums favourite topic: mpg.

I used to drive a diesel which was probably better suited to my commute (27 miles each way), but this time around I wanted a lighter car and figured petrol was probably cleaner for the environment, particularly if I could get a low emissions petrol. Hence this tiny, turbo charged engine with cylinder shut down. Yes, despite supposedly having 10hp more and whole second faster 0-60 time, it's way slower in the real world than the old diesel was.

Since it's a new car I figured it would be nice to keep track (ish) and see how the car MPG improves from new, for roughly the same kind of driving. So, I present the below:



This is horribly unscientific, so don't start pouring over the detail. It's also probable there's a simple correlation with something like temperature rather than mileage - we'll have to wait until temperatures start decreasing to be sure. But if you imagine the chart starts in early feb and ends in april you could well see a temperature correlation instead.

And for the record, it's about 10-12 mpg behind the diesel, which I'll take.

Oh and more musings: those are tank fill to tank fill figures. The onboard computer overestimates by at least 1.6 mpg on the long term average computer. The short term average seems even worse at over estimating, but that could be because short blasts are far worse for economy than I expect so I mentally try and ignore them

Another inaccuracy is the fuel gauge. At 245miles from filling it shows 1/4 gone. In the next 245 miles it goes down to 1/8 remaining and the warning light. So same miles gives 2/8 and 5/8s of the display, depending on where in the gauge you are. Acceptable for a non-linear dial perhaps, but frustrating for a digital readout!

[DanceswithUnix]

Does it make you grin? That is my simple test. I noticed there was an MG Midget parked in our work car park the other morning. By modern standards they are slow, smelly, uneconomical death traps but just seeing one gave me a really big smile

Not sure how you would measure that. Grins per Week?

it's way slower in the real world than the old diesel was.

Is it really though? The kick in the back from modern diesels feels quick, but that isn't the same as *being* quick. My diesel feels not far off my wife's petrol car, but if she puts her foot down the extra BHP she has is quite apparent as she sails off into the distance. The difference is that my diesel gives a big shove in the back when you hit the loud pedal, hers doesn't quite shove the same but that push doesn't let up until 7500 rpm.

How is the car on oil consumption? Have heard a few horror stories from the big Audis recently. Someone was telling me about the new A5 he bought, Audi even rebuilt the engine top end and it still drinks something like a litre a week!

[cheesemp]

Another inaccuracy is the fuel gauge. At 245miles from filling it shows 1/4 gone. In the next 245 miles it goes down to 1/8 remaining and the warning light. So same miles gives 2/8 and 5/8s of the display, depending on where in the gauge you are. Acceptable for a non-linear dial perhaps, but frustrating for a digital readout!

It a consumer trick. I can't remember where I first heard this but found this link that explains it. It down to the fact that consumers like the car to register near full for a long time, then drop to near empty quite quickly. They therefore make the car report it like that.

[kalniel]

Does it make you grin? That is my simple test. I noticed there was an MG Midget parked in our work car park the other morning. By modern standards they are slow, smelly, uneconomical death traps but just seeing one gave me a really big smile

Not sure how you would measure that. Grins per Week?

Satisfaction

No, at least not yet, compared to the old car on the daily commute, I've not yet found an occasion to head for thrills primarily.

Is it really though? The kick in the back from modern diesels feels quick, but that isn't the same as *being* quick. My diesel feels not far off my wife's petrol car, but if she puts her foot down the extra BHP she has is quite apparent as she sails off into the distance. The difference is that my diesel gives a big shove in the back when you hit the loud pedal, hers doesn't quite shove the same but that push doesn't let up until 7500 rpm.

Could be - I remember one of my first thoughts with the old car was that it was too short geared - I found myself changing gears more quickly than expected. The new car can be driven in a similar manner, but doesn't need to be.

However my usual measure is accelerating off roundabouts (much of commute is dual carriage way sections between roundabouts - not quite to Milton Keynes standards though!) Without even trying the old car basically out-dragged all but the most angry BMW drivers reving the nuts off their cars. With the same level of effort the new car is essentially equal to everything else. This is on one hand much safer since I am now where people expect me to be, but on the other, annoying since it's harder to drive defensively and give intention to any idiots trying to straightline a roundabout in the wrong lane.

Lower torque, and arriving higher up the rev range entirely to blame, as you describe. If I revved the nuts off it then maybe I'd find it as quick, but that's not real world really, and I'd probably pay the price in fuel/oil.

How is the car on oil consumption? Have heard a few horror stories from the big Audis recently. Someone was telling me about the new A5 he bought, Audi even rebuilt the engine top end and it still drinks something like a litre a week!

Too early to tell - hasn't needed any yet for the first 4k miles, should check level soon regardless though. Old one (2.0tdi) was worse than my previous astra, but still pretty good and once settled into my ownership never needed topping up before (my voluntary) oil change at ~9-10k miles.

What is odd though is the amount of water vapour that comes out of this engine - even fully warmed it there's a mini sauna following it on gear changes/up hills. Very normal according to the rep (he mentioned it on his before I even got a chance to). It is clearly just water, and coolant level isn't decreasing at all, so I put it down to the trick manifold they've got on this engine and heat exchanging working rather well.

[DanceswithUnix]

It a consumer trick. I can't remember where I first heard this but found this link that explains it. It down to the fact that consumers like the car to register near full for a long time, then drop to near empty quite quickly. They therefore make the car report it like that.

I usually go by the trip computer expected range. Seems a more useful measure to me, though it does in my car go up and down a bit as the recent mpg changes for different trips.

[Dareos]

as a friend just pointed out to me over a very similar discussion, fuel gauges are only useful twice, when they are showing full and when they are showing empty

[kalniel]

It a consumer trick. I can't remember where I first heard this but found this link that explains it. It down to the fact that consumers like the car to register near full for a long time, then drop to near empty quite quickly. They therefore make the car report it like that.

That's not what I expect from german engineering!

Clearly they know the number of litres left in the tank, since they calculate a 'range remaining' figure - wish there was a way of displaying that actual value. As it is, I'm left doing what I've done on cars since the year dot - figuring out the usual range based on the kind of driving and seeing how many miles I've covered since I last topped up - which is fine, but makes partial top ups slightly more arithmetic heavy.

[DanceswithUnix]

That's not what I expect from german engineering!

Clearly they know the number of litres left in the tank, since they calculate a 'range remaining' figure - wish there was a way of displaying that actual value. As it is, I'm left doing what I've done on cars since the year dot - figuring out the usual range based on the kind of driving and seeing how many miles I've covered since I last topped up - which is fine, but makes partial top ups slightly more arithmetic heavy.

I would hope that the ODB2 information would be more accurate, in which case a cheap bluetooth reader and something like this could tell you: https://play.google.com/store/apps/d...hCommand&hl=en

[herulach]

On the wash using tonnes, you can change the frequency with vagcom. Cables are available from eBay but you'll need legit software rather than what comes with it ofc.

Let's you change loads of stuff stemei.de was where I got the instructions for the leon from.

[Butcher]

As I have a pretty similar car, it's somewhat useful for comparison...

-It takes far too long to book an appointment with Audi. Nearly a month unless there are cancellations. They're very apologetic about the backlog, and aren't trying to claim it's only this one occasion, but it's been the situation since Christmas. However had I known when I'd bought the car then it'd have been factored into the purchase decision. Hire some more people and get some more courtesy cars!

Really? I got one yesterday for this Tuesday! And I'm not sure I've ever had to wait more than a couple of weeks. Presumably varies by dealership a fair bit, have you checked to see if there is another one within a reasonable distance? You can get an appointment much faster if you don't need a courtesy car in my experience too (they will do pick up and drop off).

I used to drive a diesel which was probably better suited to my commute (27 miles each way), but this time around I wanted a lighter car and figured petrol was probably cleaner for the environment, particularly if I could get a low emissions petrol. Hence this tiny, turbo charged engine with cylinder shut down. Yes, despite supposedly having 10hp more and whole second faster 0-60 time, it's way slower in the real world than the old diesel was.

Mine doesn't feel particularly boot you in the back fast like a diesel does either, but it is fast in the real world. Very fast, but you only really notice it if you're either watching the speedo or watching other cars get burned off.

This is horribly unscientific, so don't start pouring over the detail. It's also probable there's a simple correlation with something like temperature rather than mileage - we'll have to wait until temperatures start decreasing to be sure. But if you imagine the chart starts in early feb and ends in april you could well see a temperature correlation instead.

I've not been tracking mine so I don't know if my MPG has varied with temperature as a comparison. Anecdotally it feels like it has decreased recently, but I may have just been booting it more since it's been dry.

Does it make you grin? That is my simple test. I noticed there was an MG Midget parked in our work car park the other morning. By modern standards they are slow, smelly, uneconomical death traps but just seeing one gave me a really big smile

Not sure how you would measure that. Grins per Week?

Mine definitely gets me a lot of those.

How is the car on oil consumption? Have heard a few horror stories from the big Audis recently. Someone was telling me about the new A5 he bought, Audi even rebuilt the engine top end and it still drinks something like a litre a week!

Mine's not needed an oil top up outside of having the oil changed at it's first service; seems very engine specific. AFAIK the small petrols aren't prone to oil usage.

Lower torque, and arriving higher up the rev range entirely to blame, as you describe. If I revved the nuts off it then maybe I'd find it as quick, but that's not real world really, and I'd probably pay the price in fuel/oil.

I just rev the nuts off mine (6k+ rpm happens most every drive). I think having the auto gearbox makes that easier though as it will kickdown if you plant the throttle.

That's not what I expect from german engineering!

Clearly they know the number of litres left in the tank, since they calculate a 'range remaining' figure - wish there was a way of displaying that actual value. As it is, I'm left doing what I've done on cars since the year dot - figuring out the usual range based on the kind of driving and seeing how many miles I've covered since I last topped up - which is fine, but makes partial top ups slightly more arithmetic heavy.

I tend to just use the range remaining display all the time and ignore the fuel gauge for the most part.

On the wash using tonnes, you can change the frequency with vagcom. Cables are available from eBay but you'll need legit software rather than what comes with it ofc.

Let's you change loads of stuff stemei.de was where I got the instructions for the leon from.

The software is mega pricey for just that, if you can find someone nearby that already has it that's a better bet (try audi-sport.net, there's a list on their forums). I found someone to enable the oil temperature in DIS on mine, it took about 5 minutes.

[kalniel]

Really? I got one yesterday for this Tuesday! And I'm not sure I've ever had to wait more than a couple of weeks. Presumably varies by dealership a fair bit, have you checked to see if there is another one within a reasonable distance? You can get an appointment much faster if you don't need a courtesy car in my experience too (they will do pick up and drop off).

In this case it didn't make a difference about courtesy car, but in the past you're right, it can do. Yes I'll have to look for other nearby ones, it is presumably specific to this dealership, though they boast that they've got the second best survey ratings in the country... the survey doesn't usually ask how long you had to wait to get your car into service, only how long it stays there

Mine doesn't feel particularly boot you in the back fast like a diesel does either, but it is fast in the real world. Very fast, but you only really notice it if you're either watching the speedo or watching other cars get burned off.

I think this might be explained by:

I just rev the nuts off mine (6k+ rpm happens most every drive). I think having the auto gearbox makes that easier though as it will kickdown if you plant the throttle.

Which might also explain:

Mine definitely gets me a lot of those[grins].

I tend to just use the range remaining display all the time and ignore the fuel gauge for the most part.

What sort of range do you get from a tank then? Hitting 6K on the revs can't do the economy all that much good, though I guess it's not too bad if it helps you get up to speed quickly before cruising. My first car was a mk2 golf gti and I used to go for grins (well, I was in the US - petrol didn't cost anything there ) and the economy was still pretty good (amazing by US standards).

[DanceswithUnix]

Hitting 6K on the revs can't do the economy all that much good,

I think that depends on your mindset. If you really wanted economy over all else, you would be taking the bus

My previous car was a big petrol v6 Alfa 166, I used to sometimes play games seeing if I could get over 30mpg on the way home from work which was quite stop start over windy country lanes so really hard to keep a steady pace but it could be done. If the roads were completely clear so I could drive like a hooligan I might get 24mpg instead. So that is a 25% improvement in economy driving in a style so slow it could be dangerous if there were other people on the road. In normal use I probably hit 7k rpm on a daily basis if conditions safely allowed, and otherwise just drove normally and got about 26mpg. I find the killer isn't spirited driving, it is road works; trip average can drop like a stone if held up in stationary traffic.

Still miss that car

[kalniel]

I find the killer isn't spirited driving, it is road works; trip average can drop like a stone if held up in stationary traffic.

One thing (about the only thing) I think we can thank the official mpg rating test for is the proliferation of stop-start in cars - not the automation per se, but the beefing up of the battery/starter motor to allow it to be used far more. The system in the Audi is very intuitive in my view, and means some of my best mpg figures happen when in slow moving traffic - there is a window of speed when the economy isn't so good, but generally it's no longer the bane of economy like it used to be.

[Butcher]

What sort of range do you get from a tank then? Hitting 6K on the revs can't do the economy all that much good, though I guess it's not too bad if it helps you get up to speed quickly before cruising. My first car was a mk2 golf gti and I used to go for grins (well, I was in the US - petrol didn't cost anything there ) and the economy was still pretty good (amazing by US standards).

About 350 miles give or take. My long term average from the DIS is 29.2 mpg, which I consider quite good really, for the car. I've seen 40 mpg on an hour long drive when I was stuck in traffic doing ~50 mph. Motorway cruise average is around 35 mpg, driving home average high 20s (it's all B roads).

And yes start/stop works a treat on this car.