Prius Mpg

[Gav rav]

Hi all

am thinking of getting a prius for my mrs who does a 20 mile commute every day

have seen lots of mixed reviews on mpg, what could we expext on such a commute?

As not sure if i ahould stick with derv?!

Thanks

[Cyker]

If it's a straight motorway run a good derv will do better but if it's more trafficky then the Prius will do pretty well.

The difference won't be actually be that much tho' - maybe 5mpg either way - so really it's horses for courses.

[Sagitar]

Have a look at the real-life statistics for both vehicles on Fuelly

[Gav rav]

Thnkas will check it out

i may end up getting the new derv avensis or even wait for new auris

[johalareewi]

My commute is 20 miles each way. A mix of motorway and start stop traffic in town.

On the commute in my gen3 Prius, I get around 65mpg in summer and around 55mpg in winter.

Remember that the Prius is an automatic. An added bonus in start stop traffic.

[ProfZarkov]

Hmm, is there a difference between fuel types? I used my new Prius on its first run - got 72.5 out and 69 back, 50 miles each way.

However, I then filled up with supermarket fuel and I can't even get up to 60 now! The average for the whole tank was 55!

I may try a different fuel (Esso) and see if it makes any difference.

[Joseph D]

Hmm, is there a difference between fuel types? ... I may try a different fuel (Esso) and see if it makes any difference.

Hi Prof,

Yes there is. Make sure you use the RON 95 (as recommended in the owner's handbook) variant of the brand you use. Using RON 98/99 won't do your car any harm per se, but will give slightly less mpg and as it is more expensive, it is just a waste of £'s.

Also the fuel companies need to change the formulation of the fuel for summer vs winter (for technical reasons) and the winter formulation does not give as high mpg's as the summer formulation. You can see this trend on Fuelly quite effectively. If you want to read the full technical details see the article linked to in this post. As well as that Winter motoring costs a few mpg's in and of itself due to the lower temperatures.

Finally, for best fuel economy ensure your tires are pumped up to the recommended pressure. I run mine at +3 PSI front and rear over the handbook guideline, as I find this gives me more even wear over the width of the tyre. Using the handbook guideline pressures, I found my tyres wore excessively on the edges.

I hope this helps and you find it useful.

[johalareewi]

And from that thread there is a link to a really interesting document. See section 4.12.

http://miniwww.tripo...soline.htm#4.12

[Opifex]

...... Make sure you use the RON 95 (as recommended in the owner's handbook) variant of the brand you use. Using RON 98/99 won't do your car any harm per se, but will give slightly less mpg and as it is more expensive, it is just a waste of £'s.

Agree. When I've used it as an alternative to the 10% Ethanol fuel in France the mpg has been slightly down.

Finally, for best fuel economy ensure your tires are pumped up to the recommended pressure. I run mine at +3 PSI front and rear over the handbook guideline, as I find this gives me more even wear over the width of the tyre. Using the handbook guideline pressures, I found my tyres wore excessively on the edges.

I did try overinflating the tyres but the ride was so hard my fillings fell out

[Joseph D]

I did try overinflating the tyres but the ride was so hard my fillings fell out

In my case, I don't consider +3 PSI to be overinflated, but to be the correct pressure due to getting a more even wear pattern over the width of my tyres. I don't notice the ride to be any harder with these pressures. YMMV.

[rob the bank]

Hmm, is there a difference between fuel types? I used my new Prius on its first run - got 72.5 out and 69 back, 50 miles each way.

However, I then filled up with supermarket fuel and I can't even get up to 60 now! The average for the whole tank was 55!

I may try a different fuel (Esso) and see if it makes any difference.

May be worth a look:

http://www.toyotaownersclub.com/forums/index.php?showtopic=131470&hl= super market fuel&st=0

This was the last large chat about fuel types.

From my research this is the top 5 for mpg variation:

1, Driving style

2, Ambient Temp

3, Luggage or passengers

4, Tyre type and pressure

5, Oil type

Hope that helps.

[Parts-King]

I'm asked all the time about MPG with our chip kits, there are two major things that affect consumption

1 Driving style

2 The type of driving you do, some live in the hills, others are straight on to a motorway, some urban, it all affects the overall MPG from one driver to another

Ive had customers say they drive with a very light foot and akin to driving like Miss Daisy, only to go out on a road test and be horrified at the driving style, usually by not looking at the road ahead, heavy braking and not concentrating on what the car in front is doing, so quite an on/off of the accelerator pedal.

I'm continually amazed at how some people think their MPG will be to within a few MPG of the published figures all year round, they never will be unfortunatly

Kingo

[Joseph D]

...

From my research this is the top 5 for mpg variation:

1, Driving style

2, Ambient Temp

3, Luggage or passengers

4, Tyre type and pressure

5, Oil type

Agreed, but I would put them in this order:

1, Tyre type and pressure

1a, Correct fuel (RON 95)

2, Oil type

3, Ambient Temp

4, Luggage or passengers (on this point remove all non essential items from your vehicle)

5, Driving style

And by driving style I mean aggressiveness in acceleration and braking; and, speed.

Accelerating with a gentle assertiveness (not like a snail) allowing the instantaneous mpg readout to show 25-30 mpg for as short a time as possible (assuming you have no EV in reserve) then try for 60, 75 or 90 mpg as much as possible - all the time remembering that your driving should be commensurate with your surrounding environment. Remember also, that to average 70 mpg, you need to spend as much time (and magnitude) above 70 mpg as below.

SPEED

Doing 80 mph or more on the motorway will never get you better than 55 mpg. End of story.

You are never going to achieve really good mpg on a really busy motorway, because you end up speeding up and slowing down too much and not in a way you can pulse and glide.

The best speed for the Prius is in the range 44-55 (indicated) mph. (Also you can pulse and glide well in this range.) So if you have lots of A roads in your journey you stand to do better than if you use the motorways. Also if you have lots of towns and/or roundabouts in your trip, consider accelerating gently to only 55 indicated (max) and gliding down to 20 mph before needing to apply the brakes to make the best of poor road design - easier to do when you know the roads. Driving this way, you should easily be able to achieve 64-70 mpg.

Of course, I make no allowance for terrain in my generalisation above. You just need to do what ever it is require to negotiate hills. The only saving grace that you can hope for, is, you get to go down just as much as you went up. But you will never recover the full potential taken to get up as you recover going down. It is not always all bad though, I recently drove in the German mountains and achieved some of my best mpg's ever. I seemed to go up forever, but then when I came down that seemed to go forever too. Managed to get a fully charged Battery and then went into hyper engine braking mode. That can sound scary when you have not experienced it before, as it sounds like your engine is going to rev itself to bits. But you can have some fun with it by pressing on the accelerator gently to get it back into the glide - at which point the engine goes silent then take your foot off to go into engine braking again to bleed off some speed if required.

I hope people find this info useful.

[rob the bank]

Must admit I was going to do a top 10 and 1 to 5 would all be driving style.

My wife and I regularly drive the same car I can get 50% more mpg then she can.

Apart from towing a caravan nothing else could make such a difference, it’s all down to my driving style compared to hers.

And I must say when it comes to speed it's the time your spend getting there that makes the biggest difference and not the actual speed it self, hence you can keep the Eco light on upto 89mph with a little effort.

The way I look at it is if you want to get 70mpg then drive at 70mpg.

In the same way that if you wanted to average 60mph then the best way to do it is by driving at 60mph, not at trying to drive at 50% throttle.

[Joseph D]

... My wife and I regularly drive the same car I can get 50% more mpg then she can. ...

Agreed. I can consistently get better mpg than my wife due the difference in her style to mine. But the difference for us would be no more than 58 mpg vs 62 mpg.

... In the same way that if you wanted to average 60mph then the best way to do it is by driving at 60mph, not at trying to drive at 50% throttle.

I don't understand the last point of this re the 50% throttle thing, but if you want to average 60 mph on a journey, you would need to drive 85 - 90 mph or more, where you can, to achieve it. In my experience, YMMV.

[rob the bank]

No keep it simple :=)

Best way to get 60mph average is to drive everywhere at 60mph.

The point i was trying to make is a lot of people ask "what speed should i drive at to get "x" mpg", and the best advice is actually

try driving at "x" mpg.

[Joseph D]

No keep it simple :=)

Best way to get 60mph average is to drive everywhere at 60mph.

The point i was trying to make is a lot of people ask "what speed should i drive at to get "x" mpg", and the best advice is actually

try driving at "x" mpg.

The problem is you cannot drive at "x" mpg all the time, what ever "x" you have selected. So, in my view, it is not really helpful advice.

I get what you are saying, and while it might be simple, it is just not practical or even possible.

[ProfZarkov]

Hmm, thanks for all the replies.

I did drive the Gen II for 5 years as a company car so I do know the "how to drive a hybrid" bit.

Nothing much had changed in my driving except the fuel plus that long drive to Symonds yat was fairly flat.

I live in the Mendips and a lot of my driving is now up and down those them thar hills!!

It's virtually a new car and this is only its secong tankful, so early days.

Just a bit miffed that I could easliy keep the av. mpg in the 60's all the time for those 150 miles.

Now, I'm struggling to get to 55. Did the dealership add sommit to the fuel . . .

I filled up the "boot" with stuff (air compressor, fire exting. etc) but this would hardly add much weight.

Interesting to see that using the super unleaded makes for worse mpg, didn't think that would be so.

I must join fuelly and add my data as I go. I currently just use a spreadsheet which works out the mpg & cost per mile.

Cheers & thanks.

Steve

[johalareewi]

It's virtually a new car and this is only its secong tankful, so early days.

Just a bit miffed that I could easliy keep the av. mpg in the 60's all the time for those 150 miles.

Now, I'm struggling to get to 55.

As mentioned in the supermarket fuel thread, it could be your second tank had more ethanol added.

This has a major effect on mpgs in hybrids.

If you can, try the first garage again for your third tank to see what happens to the mpg.

[Madasafish]

It is mathematically and practically impossible to average 60mph by travelling at a constant 60mph - one hold up of 5 seconds and your average falls below 60mph.by definition.

[Joseph D]

Actually, it was just a theory proffered, it was not a statement of fact. UK petrol can have up to 5% ethanol blended with the petrol at present. It was also proffered that maybe Britain might move to 10% like France to conform to the wishes of our EU masters, but as yet we haven't.

More likely, that fuel formulation has been changed to the winter mix, which is known to yield a lower mpg. See here for details, if that interests you: 5.2 Why are there seasonal changes?

Having said that, I have driven away from a forecourt and got distressing bad average (44 mpg or something in that region) for the first number of miles, but by the end of the tank the average has improved to normal or thereabouts. I have also had the reverse. On my last fill-up, it was toward the end of a journey and fortunate series of events conspired to give me 84 mpg after 10 miles. After 240 miles, it is now 54.7 mpg mostly thanks to ( a lot of 75-80 mph) racing on the motorway.

This would be a good idea, as at least you would be comparing apples with apples, if you used the same garage and same fuel product.

[Joseph D]

... Interesting to see that using the super unleaded makes for worse mpg, didn't think that would be so. ...

I am surprised that people think this, but it does demonstrate how powerful clever marketing is. Using "Regular" for RON 95 and "Super" for RON 98 etc. If you would like to find out why regular is better than super, read here: Subject: 6. What do Fuel Octane ratings really indicate?

Of particular interest is paragraph 6.13 Can higher octane fuels give me more power?

Not if you are already using the proper octane fuel. The engine will be already operating at optimum settings, and a higher octane should have no effect on the management system. Your driveability and fuel economy will remain the same. The higher octane fuel costs more, so you are just throwing money away. If you are already using a fuel with an octane rating slightly below the optimum, then using a higher octane fuel will cause the engine management system to move to the optimum settings, possibly resulting in both increased power and improved fuel economy. You may be able to change octanes between seasons ( reduce octane in winter ) to obtain the most cost-effective fuel without loss of driveability.

Once you have identified the fuel that keeps the engine at optimum settings, there is no advantage in moving to an even higher octane fuel. The manufacturer's recommendation is conservative, so you may be able to carefully reduce the fuel octane. The penalty for getting it badly wrong, and not realising that you have, could be expensive engine damage.

Note that it said "The manufacturer's recommendation is conservative, so you may be able to carefully reduce the fuel octane." To increase performance carefully reduce the fuel octane.

Unfortunately in the UK RON 95 is as low as we can go.

HTH

[Jan&tone]

^.

If we had peteol at £4.00 a gallon yes GALLON, no bugger would worry about hybrids!

[Joseph D]

If we had peteol at £4.00 a gallon yes GALLON, no bugger would worry about hybrids!

It has been that and cheaper is approx £2.732 a gallon(uk) in the US (at present, has been as cheap as £2.133 in the last 3 months) and they sell plenty of Prii there. (And how they cry at how expensive gas is getting. )

Not sure what the point of your post was, though.

[Opifex]

... As mentioned in the supermarket fuel thread, it could be your second tank had more ethanol added. This has a major effect on mpgs in hybrids. ...

Actually, it was just a theory proffered, it was not a statement of fact. UK petrol can have up to 5% ethanol blended with the petrol at present. It was also proffered that maybe Britain might move to 10% like France to conform to the wishes of our EU masters, but as yet we haven't.

10% ethanol fuels in France are clearly marked with the E10 symbol. I've only used it twice but both times there was a marked drop in mpg. Luckily there is still plenty of normal 95 octane available.