Mpg When Driving The Prius "normally"

[EcoMan]

First of all, this post isn't intended to be a "why can't I get the full, advertised 70+ mpg" moan - I never really expected to see 72mpg.

I got my Gen 3 Prius in December 2009. Temperatures were low when I got it and got worse in the months that followed, so I expected to get a fair bit less than 70 mpg; plus the car was new so I knew to expect an improvement over time. I was getting mid 30s from about December through to about March 2010. Things improved on the mpg front, with a combination of better weather and my attempt to adopt some hypermiling techniques - by summer, I was getting mpg in the low to mid 60s, tho' I often attributed this sort of reading to occasions when I reset the trip meter on re-fuelling the car when warm (for some reason the car gives much higher mpg calculations when re-fuelled with a thoroughly warmed engine).

But, the hypermiling couldn't last. My sanity couldn't take it when driving in and out of London - which is a fairly aggressive business unless you have no day job or home to go to. So, now, over a year after purchase, my driving style has settled into what I would could normal (for London): quick starts from traffic lights, junctions or roundabouts; relaxed crawling in slow traffic; coasting down hills at about 30 mph or so; fairly high revs (usually seeing the rev-line just cross (barely) to the slim section of the HUD) for 10 mins or so a day when driving on a dual carriage way with a 50 mph limit. I do 150 miles a week (precisely 30 miles per day) and get about 380 miles to a tank. The mpg readout is about 42 mpg at the moment.

Does anyone else drive their Gen 3 like a normal car (most of the time) and, if so, what sort of mpg / range do you get?

Also, I still can't decide whether I love or hate this car - not sure if any other owners feel the same way; the ride is comfortable and the fuel economy is very good, but it looks so ridiculous from the back, has totally inert steering which (combined with the very odd weight distribution) requires constant correction and has paint work which scratches if you even breathe on it. Maybe I've just been spoiled by German car ownership up to this point.

[Grumpy Cabbie]

I'm a taxi driver and my 12 month average was 49 mpg and I'm more than happy with that. On a run I can get into the lower 70's and a daily average in heavy heavy traffic has never been lower than 40 mpg and that was in winter.

I'd double check your tyre pressures and make sure the dealers have actually put 0w20 oil in (not 5w30 like some have done) and also make sure they haven't badly overfilled the oil.

If the above is all correct then I'd say you're probably expecting too much. The Prius isn't magic. You can't floor it everywhere and expect it to get 75 mpg. Are you a lead footed petrolhead? as getting anything less than 45 mpg out of the Prius is hard to achieve. I'm a taxi driver, I spend all day in heavy start stop congested traffic, I don't hang about between jobs and the displayed average over the last 2 months/3000 miles since my last service is 51mpg displayed (probably 48-49 mpg actual). I'm also unsure of your figures - at 380 miles to a tank I get about 52/53 mpg and that is checked both by the cars trip computer and me checking it manually.

Sounds like you don't like the Prius so why not flog it and get something that appeals more to your driving style and make yourself happy. You shouldn't have a problem selling it with petrol priced as it is.

[EcoMan]

Actually, that's very reassuring - it sounds as though you're getting about the same mpg as me and probably drive the car the same way as I do. The 42 mpg readout today might not be representative (and I've not been looking at the ECO mode mpg graphic so much for the past few months as it was too distracting); I've really been going on how many miles I get to a tank - so you're prob right that it's actually about 52 mpg or so.

I've checked tyres, but not checked oil.

As I say, it's love/hate. Yes, I am a petrolhead, but I'm trying to be more sensible for commuting to work so will keep working at it!

[Jan&tone]

I work 20 miles away from home, all country lanes, twisty and most is 60 mph limit. If i use the Prius I seem to get around 52-55 mpg, but when we visit ma-in-law with a 78 mile each way, a13/m25 south/m3 i rurn in around 65mpg sticking to around 67mph with cruise control on...

I'm happy with that!

[Grumpy Cabbie]

Actually, that's very reassuring - it sounds as though you're getting about the same mpg as me and probably drive the car the same way as I do. The 42 mpg readout today might not be representative (and I've not been looking at the ECO mode mpg graphic so much for the past few months as it was too distracting); I've really been going on how many miles I get to a tank - so you're prob right that it's actually about 52 mpg or so.

I've checked tyres, but not checked oil.

As I say, it's love/hate. Yes, I am a petrolhead, but I'm trying to be more sensible for commuting to work so will keep working at it!

If its a company car just think of all the money you're saving and maybe treat yourself to a weekend car? If the Prius is your own then what about pimping it up a little? There are some good looking Prii on the US forum from the Japanese Prius tuning group! Some are lowered, nice alloys and skirts but all in a tasteful and not chavvy way.

It's a halfway measure but you'll look good and save money.

[EcoMan]

If its a company car just think of all the money you're saving and maybe treat yourself to a weekend car? If the Prius is your own then what about pimping it up a little? There are some good looking Prii on the US forum from the Japanese Prius tuning group! Some are lowered, nice alloys and skirts but all in a tasteful and not chavvy way.

It's a halfway measure but you'll look good and save money.

Thanks - I do like the look of the 10th anniversary wheels ... Anyway, thanks again :D

[Cyker]

Sod the mpg! RAG EEEEET!!!! :D

Hmm, I wonder what the torque on that electric motor is

[Ancient Nerd]

Haven't you tried annoying the boy racers by leaving them standing when the lights go green! It's not too economical, but just occasionally...

I think as Mr Clarkson would have it, the Gen II has 400 torques from the electric motor(s). The Gen III, just over half that. That takes you to the speed where manual cars have almost engaged the clutch fully, and are nowhere near maximum torque. Then the petrol engine cuts in! It runs out of steam eventually, but the shape of the acceleration curve is such that the Prius has travelled further by the time it reaches 60, so is further ahead than you might expect.

The downside of the Gen II is that the traction control saves the transmission from all that torque at once, so you learn not to use it all until the car is moving.

[Dizzo]

You're spot on about the steering Ecoman, my Prius just the same, my faithful old Rover used to sit on the Mways and I could steer it with one finger, the Prius needs constant attention! 4 weeks after I bought it I hit an armco cos I switched channels on the radio!! But mpg-wise it's amazing, average over a year 58mpg. I do a lot of mway driving and what makes a big difference is slip-streaming whatever's in front of you, not easy in London! But its no good giving it 80mph, I average 65. And servicing is cheap. My mates all impressed - loads of room in the back, so quiet, but so ugly!

[johalareewi]

I got my Gen 3 Prius in December 2009. Temperatures were low when I got it and got worse in the months that followed, so I expected to get a fair bit less than 70 mpg; plus the car was new so I knew to expect an improvement over time.

I got mine in Nov 2009 so also had the cold winter but did manage about 45mpg. Now the car has run in and the tyre pressures are sorted and I have adapted my driving style a bit I managed to average 53mpg this winter. I am not a petrol head but I don't drive everywhere at 40 either so am not sure why your mpg is so low and you can only get 380 miles from a tank. I can now get 500 easily and once managed 600. It does sound like there might be something else in the mix like GC suggested. Do you still have the stock tyres or have you replaced them? You do need to get low rolling resistance tyres (and keep the pressure topped up) otherwise the mpg bombs.

[johalareewi]

... but so ugly!

But the ugly duckling turned into a swan

[Seamaster73]

I had no difficulty achieving 65 mpg during the extended (four day) test drive I had last year, driving quite normally (mix of city and 60-70mph motorway).

If you're a company car driver, remember that the money you're saving in BIK tax is as big an inducement to retain your Prius as the MPG!

[EcoMan]

Thanks for the replies. I've done a bit more critical self-appraisal overnight and think that I am probably still being too heavy footed for the car, even tho' aggressive driving is the norm in the London commute. After posting on here yesterday, I took it easy on the way home and could see the mpg rising to 46.6 or so - i.e. trying to just feather the accelerator etc. But, in the dog-eat-dog morning commute, it was impossible.

I have the original tyres on the car and checked tyre pressures about 2-3 weeks ago (but will do it again tomorrow).

Getting 500 miles from a tank would be immense.

Apart from getting good mpg (which I need to improve on), the Prius is saving me loads on Congestion Charge (£10 per day), insurance and road tax.

I'll confess that my last car was a BMW M5 which was great fun for weekend motorway cruising, but a killer in town (12 mpg) and I've picked up some bad habits wrt the loud pedal ...

[johalareewi]

If you can keep the HSI out of the PWR zone (apart from the odd short burst) you can increase mpgs a lot. The sweet spot for the petrol engine effeciency is just before the PWR bar starts so if you can accelerate with the HSI there, you can improve the mpgs. Another trick is to use ECO mode in start stop traffic to encourage the prius not to use the petrol engine unless really really necessary.

[cbcdesign]

Thanks for the replies. I've done a bit more critical self-appraisal overnight and think that I am probably still being too heavy footed for the car, even tho' aggressive driving is the norm in the London commute. After posting on here yesterday, I took it easy on the way home and could see the mpg rising to 46.6 or so - i.e. trying to just feather the accelerator etc. But, in the dog-eat-dog morning commute, it was impossible.

I have the original tyres on the car and checked tyre pressures about 2-3 weeks ago (but will do it again tomorrow).

Getting 500 miles from a tank would be immense.

Apart from getting good mpg (which I need to improve on), the Prius is saving me loads on Congestion Charge (£10 per day), insurance and road tax.

I'll confess that my last car was a BMW M5 which was great fun for weekend motorway cruising, but a killer in town (12 mpg) and I've picked up some bad habits wrt the loud pedal ...

Even if you average 40MPG driving it hard its still 3 times as economical as your BMW was so thats got to be a plus! :)

[Doesn'tExist]

I commute into london, and around london to Farnborough. When I have the Prius I have no trouble get an indicated 72mpg, I always drive maximum speed wherever traffic permits which includes an indicated 80mph on the motorway. Just keep it out of that PWR zone and in stop start traffic switch to the ECO setting and it is easy.Heck I even get 34mpg out of my Audi 3.0 petrol quattro automatic when adopting the same driving style. You don't have to be a slough, just don't sprint from light to light as that is a waste of engergy and even increased heart rate.

[Wattsy]

I'm also unsure of your figures - at 380 miles to a tank I get about 52/53 mpg and that is checked both by the cars trip computer and me checking it manually.

I have a GEN2 rather than a GEN3 Prius but I'm surprised at this calculation; does the GEN3 have a really small fuel tank? I think my GEN2 has a 45L tank - so if I got 380 miles to a tank, I'd be getting about 38mpg. Or have a misread what was being said somehow?

Pete

[Grumpy Cabbie]

The gen3 Prius does indeed have a 45 litre tank but I fill up at about 50-60 miles range left. My last fill up at 60 miles left was for 32 litres! It is said (though I have never dared try) that there are about 100 miles left once the car gets to zero miles range.

But I prefer to err on the side of caution than run out of fuel and knacker the HV Battery.

[Glyyde]

when the indicator shows 0 mile left, I could normally pump around 38-39 liters of petrol still. Never actually managed to pump more than 39 liters to be honest. Then again, I dare not wait any longer when it says 0 mile left.

I rarely drive into London. But the mileage I get when in there are normally quite good due to the relatively flat surface. From memory, I was able to get something in the range of 55-60mpg in traffic. That compare to my normal commute of 3 miles one way to work, that only gives me an average of 52mpg with the recent temperatute, thanks to an almost all uphill road on the way to work.

[Dizzo]

I definitely get more MPG with a following wind! A lot of my journeys are down south, and on the return to Leeds I reckon I get 2mpg more than on the way down. Must be the prevailing South Westerly wind, unless it's downhill all the way returning from the south!

[Seamaster73]

I have to drive my Mercedes A170 really thoughtfully to get 45mpg. I found I could better that by some margin in the Prius without even trying.

[Grumpy Cabbie]

I definitely get more MPG with a following wind! A lot of my journeys are down south, and on the return to Leeds I reckon I get 2mpg more than on the way down. Must be the prevailing South Westerly wind, unless it's downhill all the way returning from the south!

It's all that hot air from London pushing you back up towards civilisation

[Opifex]

After 442 miles I filled up on Saturday with just under 35ltr which works out at 57.5mpg. The journey had included about 350miles of French motorway at upper 70s mph and the rest was a mixture of local roads and small villages. I really was hoping to crack 60mpg this time, so a bit disappointed, but I do keep reminding myself that it is almost twice what I would have got from the old Saab a few months ago.

I do take the point that the consumption would improve if I went 10mph slower on the motorways, but when the rest of the traffic is doing 80+mph it is very difficult to change lanes to overtake lorries if your speed is much different.

After filling up I reset the trip meter and we set off for a sightseeing trip. With outside temperatures around 20oC, the mpg started to rise and at one point actually hit 80mpg. After 50miles we stopped to explore, by which time the mpg had dropped to 74mpg. In the evening on the way back to the B&B the temperature dropped and so did the mpg, so it was down to about 69 in the end.

As an aside, on the way back we were stopped at a checkpoint for a random breath test. These are becoming more common across France so anyone going this summer should be prepared.

[Sagitar]

Single journey figures, or even single tank figures, don't necessarily mean very much and you certainly cannot depend upon the car computer figures.

When I filled up this morning, the trip computer showed 59.2 m.p.g. for the tank. The real figure for the tank is 56+ m.p.g., but my long term average is 54+ m.p.g.

That is a good figure for me, with a lot of short, urban journeys from cold.

If you really want to know what you are achieving it helps to use something like Fuelly.

[Ancient Nerd]

Your error sounds about right.

In my case the computer mpg is just over 7% optimistic. This varies quite a lot between individual tanks, from 2% to 12%. So my overall true consumption is 56.6 mpg, while the computer figure is more like 60.7 mpg.

The previous Gen II was closer, with an error of 3% (true 55.4mpg, computer 57.1), but a much wider variation (from -6% to +14%).

If you think that the Gen III fuel consumption isn't much better than the gen II, that's because, over a similar timescale, the Gen III has seen two winters, while the Gen II was just one. And of course, correspondingly less summer.