Prius+ Vs Prius Gen 3 From 2009

[Ten Ninety]

20mph is pretty inefficient for a cold engine so you might actually be better off running EV mode if you can then drive at a more efficient speed for the ICE to warm up after that first mile. I guess the only way to really find out is to repeat the process every day over a week and see if your real-world average changes. I'm not sure that I'd trust the MFD to measure this, mind. I have long suspected that the more you use EV (or regular milkfloat mode) then the further out the MFD reading gets from actual consumption.

Ref your earlier point about 73mph getting better economy than 68mph; I strongly suspect this is anomalous. It definitely contradicts my experience where anything over 70 has a notably detrimental impact. In fact, I have found that the relationship between economy and road speed is pretty linear from around 50mph upwards. Going slower makes it harder to coast but above that point I find the faster you go, the more petrol you use. The CVT isn't like a normal car where you're stuck in a particular gear - with a manual box there are definitely points in each gear where going faster can give better economy - but the CVT just seems to run the most efficient engine speed for whichever given road speed you choose. Without wishing to cause offence, I would cautiously and respectfully suggest (having undoubtedly done this myself in the past) that the motorway experience you described may perhaps have been a case of you seeing what you wanted to see because you were uncomfortable driving at the lower speed for other reasons.

[PeteB]

...Ref your earlier point about 73mph getting better economy than 68mph; I strongly suspect this is anomalous. It definitely contradicts my experience where anything over 70 has a notably detrimental impact. In fact, I have found that the relationship between economy and road speed is pretty linear from around 50mph upwards. Going slower makes it harder to coast but above that point I find the faster you go...

...the CVT just seems to run the most efficient engine speed for whichever given road speed you choose...

That can often be the case and conforms to conventional wisdom, but the THS has many surprises up its sleeve.

Before I moved permanently to Norfolk 3 years ago, I lived in Luton and visited here at least once a month. The trip was 120 miles each way, much of it dual carriageways with 60/70 mph speed limits. I generally travelled up late Friday evening (after 8pm) and returned after breakfast on Sunday in the summer and after lunch in the winter (less traffic). I use cruise control a lot on the trip.

I always started with a full tank, and there were two people on board with luggage for a weekend away, so the car was always loaded similarly. Sometimes I would cruise up to true speed limit for the whole journey, and sometimes I would try to beat a previous record fuel consumption and limit the speed to 55-60 on the speedo. I would do nothing else differently, and often use the resume on the CC after a roundabout to rebuild the speed.

On average my calculated tankful consumption was 2½ mpg worse the the display, so I felt it safe to use the display for long journey comparisons. Obviously, the air temperature, wind and rain would be a factor (I always used dipped headlights all the time before having daytime running lights and always had the climate control set to 18C with air-con on normal (the Classic Prius had a MAX a/c mode which ran the engine a lot more - mechanical compressor on the Gen 1 Prius)).

Display journey mpg would vary between low 50s and upper 60s, but sometimes it was the slower journeys that got lower scores, and sometimes faster ones that got better mpg, in relatively similar weather.

On the same journey my Gen 3 T3 will often achieve low 70s even when cruising at the true limit all the way, and easing off the top speed doesn't seem to improve it noticeably (only other difference is I am now alone in the car for this journey).

I have no explanation for any of this!

When I drove a 2007 Prius with an additional display hooked up, I noted that when cruising at any constant speed between 30-70 mph on a level road the ICE settled at around 1100 rpm.

[johalareewi]

There is also the 'apparently completely random' factor which - after a year of trying to tie it down - still baffles me. On at least one journey each week I will find my average dropping by up to 10mpg for absolutely no discernible reason. There is no relationship to weather, temperature, congestion or indicated battery charge level but the real-time mpg meter will be notably lower throughout the journey and the average for the journey will be hit. The only thing I can think of is some kind of battery conditioning process that kicks in from time to time and puts extra drain on the engine.

Could be wind speed and direction.

A 5mph headwind can make a sizable dent in mpg when traveling at speed.

And a 5mph tailwind can make a nice boost in the same situation.

Air density also has an effect but not as much as wind.

[Ten Ninety]

Air density also has an effect but not as much as wind.

It's not been wind on the occasions I described. Wind is definitely a noticeable factor but I could point to occasions when I've had a significant tail wind and still seen the drop. I did wonder about air density, although at the speeds I travel I didn't think it would have so much of an impact. However, I guess it affects engine efficiency as well as aerodynamic drag so maybe that is the answer.

Display journey mpg would vary between low 50s and upper 60s, but sometimes it was the slower journeys that got lower scores, and sometimes faster ones that got better mpg, in relatively similar weather.

On the same journey my Gen 3 T3 will often achieve low 70s even when cruising at the true limit all the way, and easing off the top speed doesn't seem to improve it noticeably (only other difference is I am now alone in the car for this journey).

Interesting. Wind and, perhaps, air density as suggested above might explain the unexpected differences between slower and faster journeys. However, it wouldn't explain your experience of easing off the top speed having no noticeable effect.

That really doesn't tie in at all with what I have found, which is that I need to really be under 70mph to see a consistent indicated average of 70mpg on a dual-carriageway run. However, to be fair, you've had a lot more experience of that kind of driving in a Prius than I have, as most of my time is spent on single-carriageways at lower speeds. My wife's Auris HSD, which does the longer runs in our household, will definitely do significantly better mpg at 65mph than it will at 70mph. However, it also has a poorer aerodynamic profile than the Prius so I appreciate it can't be directly compared.

[OldSkoO1]

Another newbie question.

Is there a difference between pressing the ev button compared to keeping it left of centre on the hsi?

I read another post that the ev mode can go up to 25 mph once warm but I have no problem staying left on the hsi up to about 45mph on the flat and it still reads 100mpg... Or is this 100mpg with engine assist?

Is there a difference? Like ev is pure Battery and left of centre is literally hybrid mode ie sometimes Battery sometimes Battery & engine. Im confused as I read ev mode is a max of 25 mph but I see 100mpg staying left at much higher speeds.

[Grumpy Cabbie]

Yes

EV mode is restricted to 20 mph or upto 30 mph in certain circumstances. You can also go right of centre but not into the power band. (not sure if the Auris has a similar display).

Electric use in Normal mode is restricted to left of the centre band only but upto about 40 mph in very very certain circumstances. Emphasis on the word 'upto'. Sometimes on down hill sections you might get electric drive at higher speeds.

But this is a simple explanation. Nothing is black or white with the hybrid. Electric use in Normal mode varies depending on Battery level. If the level is low the car will switch the engine on quicker and at lower speeds. If the Battery level is too high the car will rev the engine, using no fuel, to burn off charge. It will also run like an electric car going into the power band without switching the engine on. This happens only if the HV Battery is totally full and the charge 'burns' off fairly quickly.

The above is the simplified version :)

[OldSkoO1]

Yes it certainly seems like a very complex system. I was out tonight and had chance to run a few experiments which I couldn't resist. One was to see how far it would go on ev.

I had a few miles of 30mph road with a loop back. I initially tried to press the ev mode button but it complained 30mph was too fast even thought the road was flat.

I continued in Eco mode with 9 bars of Battery after a long brake regen before I started. (I assume the Battery indicator is 10 bars - I was right up to the last space under the nipple which was empty). Anyway, I gave up after 5 miles and 99.9mpg showing on the trip, roads were quiet but I did have to brake 3 or 4 times and I used ICE for acceleration around that many times too. Whatever it does, it does it very well as I still have 3 bars left on the Battery at 99.9mpg and I kept the speed at 30mph on the flat and cruise was always left of the hsi.

I tried some hypermiling after that, resetting the trip, over a few miles of dual carriageway, including hills and different speed limits, so bit of a mix. Even though the engine was warm I got an indicated 88mpg. Pretty incredible.

[Grumpy Cabbie]

The higher speed in EV mode is quite tricky to get. It depends a lot on internal HV Battery temperatures - too cold and it will kick out at 20 mph, too hot and it won't even engage EV mode or will kick out at 20 mph. Too much a/c running and it won't engage or will kick out at 20 mph. Too much regen and the HV gets too hot and won't engage EV. You're seeing a trend here :)

You really have to experiment. Try a long (mile+) steep hill in a 40+ mph zone without using B mode, but be careful when regen switches off. Then see what the car does. Have fun :)

[OldSkoO1]

Very pleased, after some minor adjustments in driving style I'm now average 70+mpg on my 50 mile commute. Today I got 74mpg from stone cold.

Great thing is I'm not driving super slow, acceleration is using half way into pwr if I need too which suits most following traffic apart from audis.

I've adapted how I drive and when I got my prius 57-62mpg indicated was common, now +70mpg is happening most times I drive it apart from on the motorway.

[Grumpy Cabbie]

Very pleased, after some minor adjustments in driving style I'm now average 70+mpg on my 50 mile commute. Today I got 74mpg from stone cold.

Great thing is I'm not driving super slow, acceleration is using half way into pwr if I need too which suits most following traffic apart from audis.

I've adapted how I drive and when I got my prius 57-62mpg indicated was common, now +70mpg is happening most times I drive it apart from on the motorway.

Now you see why we all have a smug grin :)

Oh, and why many diesel drivers really hate us. I've driven more diesel models than I care to remember and could never get top 40's or very low 50's in a Prius sized car even when really really trying. Drive said diesel into a town and just watch the mpg's bomb.

I'm bored of my old Prius now and was toying with a replacement car, but I could never ever bring myself to pay car tax again, not even £20 per year. Then I couldn't really make do with a car that gets 30 mpg or even 35 mpg. That's almost doubling my fuel bill. £30 becomes £60 which is significant. Then I'd miss the smooth, quiet acceleration and the super quiet experience of sitting in stationary and slow moving traffic in town.

Other than a Tesla S or an Auris Station Wagon, I really can't think of another car that would please me on the above. The former car is the stuff of dreams and the latter is not really that much different to warrant the expense at this time.

Stuck with the ol' Prii for now it seems. Oh, and don't they hold their value well? The official price was £18,500 when I got mine, but I got a nice discount from Toyota. I was offered a trade in of £7,000 knowing its history and with a scratch on the OSR bumper. That's some holding of value for a 4.5 year old car. Maybe I'll pop her in for a Leaf?

[OldSkoO1]

Agree totally

a) trade in values are a joke! But i've also found this on other cars too. Generally i put the reg of any car i want to sell or even buy into we buy any car. It gives me a low end value. Trade in for part ex is usually 1k lower than this but its down to you to get a good purchase price.

When i bought the prius i put in the WBAC value and 90% of dealers were 2k above the WBAC value. I offered 1k above and and got the car. Actually i got it for £700 above the WBAC value so did pretty well.

But second hand prices aside (i had a auris from new a few years ago, that was 18k new T180 and i think i got 8k for it, something like that... years ago). Terrible really.

Totally agree with the hybrid / electric concept. Well not even a concept, a proven success. I've driven the auris hybrid quite a bit and i've drive nearly every toyota diesel going as my wife works for toyota. I never got more than 57mpg out of the auris hybrid, think it was one of the earlier ones if that makes a difference. It certainly seemed less efficient than my prius. I'm chuffed to be getting over 70mpg on every longer journey now, 40-50mpg on my shorter and luckily infrequent ones. I was out today in my prius and it was 73mpg over 20 miles. I did a run out this evening in my wifes rav4 2.0 diesel which is the slower one that should do 57mpg i think. I managed 40mpg dead on, its long term average is 38mpg but when i drive it i can usually coax 40-42mpg out of it, a true combined. Although it will do 48mpg on a-roads. The difference is all those diesels get a true tank average of about 38-44mpg yet the prius seems to get at least 50 - 55mpg for most people and for me i'm getting a display average of 67mpg right now.

My brother has a brand new Auris estate, fully loaded, extremely nice and he's getting mid 50's and he's still learning how to drive them. I think whilst not ultimately as capable at very high mpg's they are probably only 10% shy.

Lexus c200h is very nice too but i think the ride is a bit of an issue.

Leaf is very nice, a friend has one and for her job at the local hospital its more than capable of doing her commute and shopping trips into town but they do have a family estate for the longer trips.

That is why i like the Prius, Auris Hybrid. I honestly don't think they can be beaten. Petrol, auto, incredible fuel economy, makes a lot of sense.

Electric cars like the i3 rex are still very expensive.

As i understand it you have had a bad experience with the prius which is a shame really but i can understand why you want something new.

Despite the indifference, sticking with it is probably the best decision with your financial hat on, the cost to change probably far outweighs living with it.

[Grumpy Cabbie]

Oh I've had a few gremlins with the car, but I think it's because it was an early one - the ones with the reduced warranty of 60,000 miles total. Me thinks Toyota knew something, perhaps using cheaper parts to compete with Honda at the time. Since the recall fun and games I think Toyota upped their game and improved quality again. A lot of the reliability issues discussed on the US forum do seem to be 2009/early 2010 gen 3's.

I like the car, I love the drive, but I get bored easily and never usually get the same car twice. The Prius is now too expensive for what it is. As I said, 4.5 years ago they were £18,500. Now they're shy of £22k. That's too much for what it is. Guess they upped the price to squeeze the Auris HSD in.

But the Toyota dealers are fantastic. The breakdown cover is great and cheap as chips. Even Toyota insurance has been great - the Mrs having pranged her IQ the other day. So I like the Toyota package and there's a lot to be said for backup services and that's the reason I'd never buy a Citroen or Renault.

[OldSkoO1]

Update now i have finally got through a full tank after the partial tank

I bought this car as a commuter and run around

My other car is heavy on fuel so I care most about economy

It has got me 593.8 miles, at averagd speed of 31mph and indicated 71mpg.

Actual mpg is 67.9mpg

Incredible. The summer temperature is optimal but it certainly seems the official mpg is within a cats whisker.

This car gets slated for being way off, a lot do but my very first tank has worked out well for me.

[APS]

That is really good. It also seems to be in line with my observations comparing the displayed fuel economy versus real (calculated) in my Auris HSD 1st gen. Over the past 12000 miles or so, I've found the displayed MPG to be 5.53% above the calculated.

This matches your single tank quite well 67.9 + 5.5% is 71.6.

The difference is, I get nowhere near 70mpg in the Auris. The superior aerodynamics of the Prius is definitely paying dividends.

Sent from my iPad using Toyota OC

[Grumpy Cabbie]

The difference is, I get nowhere near 70mpg in the Auris. The superior aerodynamics of the Prius is definitely paying dividends.

Sent from my iPad using Toyota OC

Advice offered to you AND others reading the thread :)

Tyres make a big difference; are yours stock? I use cheap Bridgestone Ecopia's.

Tyre pressures: check them twice a month at least.

Oil: The 1.8 Prius/Auris hybrid MUST use 0w20 oil to get the best economy. Many dealers still use 5w30 and some car lease companies that include service costs insist on that too. Whilst that oil will offer protection to your engine, it is thicker and I found it significantly reduced my mpg's at the top end.

When I got my Prius, the gen3 had only just been released and due to my mileage I had a service within 3 or 4 months of getting the car. At that time the dealers were servicing the gen3 using the gen2 service sheet as Toyota hadn't distributed the gen3 version as yet. My dealers used 5w30 and my economy collapsed. I went back a number of time to complain as I just couldn't get anything above 59 mpg however hard I tried, yet had previously managed high 60's and low 70's mpg. The dealer did look into it and found the oil 'issue' and changed me to 0w20 asap. The oil issue has plagued gen3 and Auris hsd owners since. Some dealers are fine, some might have a rogue service tech who just uses what ever is to hand - "oil is oil isn't it?" and you're then you're charged for 0w20 and you go away happy.

0w20 is now used across the Toyota range compared to just one car back in 2009, so the problems should have been resolved. But if you didn't have your car serviced yourself (ie you've just bought it), you might want to get 0w20 in it next time.

And to add confusion, many oil manufacturers don't produce 0w20 so will try and suggest or recommend 5w30 for the gen3/Auris. Halfords and Castrol both stipulate 5w30 for the gen3 purely because they don't offer 0w20.

Clear as mud eh?

[johalareewi]

The superior aerodynamics of the Prius is definitely paying dividends.

At speed, a lower drag factor can have a significant effect.

The air resistance increases as the square of the velocity so when you get up to motorway speeds, the numbers get large. This is where small differences in drag factor have an effect. 0.1 of a large number is still a largish number.

[Ten Ninety]

In my experience, driving both Auris and Prius regularly, there's very little difference in terms of the economy they're capable of. When I take the Auris to work, I can do 80+mpg on the MFD. It's definitely capable of real-world 70+ at this time of year. Assuming, as has already been highlighted, that you're not running duff tyres or the wrong oil.

[APS]

It must be my foot or lack of patience.

I always keep my tyres at >2.5bar front 2.5bar rear.

With regards to oil I can only go on what the local Toyota garage bill me for. Every service parts list says 0-20 oil on it. So I assume that's what they put in.

My commute is 50 miles each direction (100 mile return) on motorway and dual carriage with plenty of roundabouts. Hence plenty of acceleration and deceleration. That said, I've turned it into an art form of maintaining momentum and slinging the car through the roundabouts.

I can get it to 67MPG displayed if I'm driving like an absolute snail, use cruise control as much as possible and never exceed 60mph. But that only works if the roads are pretty clear. Which is rare these days. Or otherwise I'm holding up traffic. In my view it is unacceptable to force lorries to have to overtake me just because I'm trying to hyper-mile.

I would also think that since my commute is quite long and at high speed, the engine is kept warm and even if the garage had sneekily put higher viscosity oil in there the difference would be pretty small.

[Grumpy Cabbie]

I would also think that since my commute is quite long and at high speed, the engine is kept warm and even if the garage had sneekily put higher viscosity oil in there the difference would be pretty small.

But my experience of 5w30 is that the differences ISN'T small. I guess it has been assumed by the odd dealer that "they'd never tell if we stick this in", but in a car highly tuned for economy like the Toyota hybrids, you can tell - significantly.

Maybe it's only 3% or 5%, which in a 35 mpg diesel isn't noticeable, but in a 70 mpg hybrid it is.

I can't remember if it was this thread or another in here, but I recently went for a drive of 84 miles on mostly A roads and motorway, including overtaking and a high speed (for a short time) to get away from a dodgy driver. I still returned something like 73 mpg for the trip.

I was mostly doing 55 on the A road and about 65 on the motorway (apart from the blip at ** mph :) ).

But I know from experience that if 5w30 was in, I'd have got about 57 mpg for that journey.

I'm not saying you have the wrong oil in yours, just that if one item is slightly out of perfect (tracking, tyres, tyre pressures, oil etc), then that odd percent makes a difference at the top end of economy. I guess in the same way they would knock 1/10's of seconds off a lap time if the Prius were a performance car.

Equally, traffic conditions play a part as does driving style. Rush hour is a different kettle of fish to 10 am.