Are people really getting 40+ MPG in Gen 2?

We’ve had some unusually hot weather in the UK recently, and London’s been pretty HOT, HOT, HOT . A side effect of this, for Prius owners is improved MPG.

The readings from my MFD above, are from my last tankful. Refuelling got only 42 litres into the tank, so I’ve managed 600 miles (UK) on 42 litres of standard 95 RON fuel (which is what I use).

Astoundingly, about 200 miles of the above MPG readings were achieved travelling mostly at 70 mph (GPS calibrated) from London to Eastbourne and back - with Airconditioning on minimal (life support) settings (including 2nd fan speed, recirculate, temp @ 17c) and cruise control engaged at every available opportunity.

The rest was in London, commuting back and forth to work (34 mile round trip) every week day. Again, A/C was in use everyday, particularly in the afternoons. Hypermiling protocols were engaged where prudent, otherwise cruise control was normally used during the early morning commutes (at speed limits in Average Speed Cam Zones). Driving like Ms Daisy has never been an option. Single occupant with all my work stuff in the aft cargo bay.

I now have over 105,350 miles on the vehicle, which is of 2008 vintage. To say I’m gobsmacked is an understatement. I wasn’t even trying hard!
The 2nd generation Prius is one of the most amazing and reliable vehicles on the roads today.

I’ll never cease to be amazed by this plucky Shuttlecraft on wheels!


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Given that the correct ones are over $100 each...I'd be trying a pair of cheap standard air O2s if you're not sure

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I get an easy 50 mpg this time of year and I drive my 2007 with 220k like a sports car. If I drove trying to optimize mileage I'm sure I could squeeze out 55+ mpg.

 

That is very impressive. When I drive my 2007 with 193K miles like a sports car I get low 40's. 50's for me is almost impossible, but I do get pretty consistent mid to high 40's most of the time.

 

I was a little surprised when I ran the numbers...considering the jack rabbit starts and 80+ spirited freeway runs. Was seeing about 42 mpg in the winter and 38 mpg with spirited 80+ freeway driving. Changed the spark plugs and had the MAF cleaned at 200k along with trans, inverter and coolant fluids changed. Mechanic said spark plugs where definitely due. You may see a bump with a MAF cleaning and new spark plugs.

 

I got new spark plugs at 175K when I bought the car. MAF cleaning may be happening soon.

 

Just the standard fuel over here, I don't pay for higher octane stuff.

Thanks for the tip. I was going to raise the pressures to 37 front and back (it's what I used in the VW) However if you say there is negligible difference in the back I will only raise the fronts (as the backs are currently on 35 anyway).
I'm not worried about wearing these tyres out if I'm honest, none of them match, all are worn differently and I think one wheel has lost a weight because I have a wobble through the wheel above 75mph. When I get new tyres I'll get LRR ones, balance all the rims and get my alignment/tracking checked.
All I did since I bought the car was check the tyres were legal, filled the washer fluid, checked the oil and filled the fuel tank so there's plenty I could double check.

 

That's amazing! Over my first tank (Also UK) I managed 54.8mpg which I'm happy with but always happy to pick up tips!

The fact I'm from Wales, with all our rolling hills means I'm at a serious disadvantage... Do you do a lot of pulse and glide? Or do you tend to just use cruise control and let it sort itself out?
I've got a trip to the Mendips in August so looking forward to my first long trip! most of my trips are only around 10miles each way otherwise.

 

My wife's last three fill-ups in her '07 with 125k miles:
5/3/18 -- 47.5 mpg
6/11/18 -- 50.5 mpg
7/5/18 -- 51.9 mpg

 

Side note...just got 47.8 hand calculated, and 47MFD (~44) on 400+ miles on this tank...ALL NC mountains/backroads...285k orig T-Batt, AC on full blast, ngk basic $1.94 v grooves lol

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48.8 in this tank thru the mountains!

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432 miles, 8.852 gallons

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The tank is FULL no bladder issues lol

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On my 2008 I remember a couple of tanks above 50 mpg but very few, most were 46-48.
I found rolling hills not to be a problem unless you had to start and stop a lot.

 

Typically low to mid-40's on my 2007 and 2008, except COLD winter when it drops down closer to 40, maybe even 38 or 39. I most consistently ran 46 mpg until recently when it's been closer to 43. Mileage is 90,000 and 70,000, respectively.

 

285984 right now
278350 6 weeks ago when I bought her ..

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Your mpg will improve with time, as I clearly recall my first tank on my 2008 Prius being similar to yours. Coming from a vehicle that gave me no better than 30mpg (UK) on a good day (and 27mpg average - Mazda MX-3), I’ll never forget the elation of getting 450+ miles from my first tank that hadn’t even been full in the first place!

I tend to use cruise control a lot these days, basically wherever possible, especially when I have a clear road ahead. It’s also very useful IF you want to keep to the speed limit in a 40mph and upwards zone. I’m not bothered about taking hills while on cruise control.

From my point of view, I’ve paid for a vehicle that has this technology built in; I might as well get my money’s worth. This is the 21st century; Tesla’s have their rather misnamed “Autopilot” really a very advanced form of Adaptive Cruise Control. The least I can do is utilise the “Auto throttle” built into my relatively vintage 10 year old Prius.

So portions of my commute are accomplished using cruise control - the nice thing is, it yanks you up a hill with your engine whining like a twin turbofan liner taking off, then it cuts all power at the peak, and drops you down the other side of the hill, dumping energy from regenerative braking back into your HV traction power pack. It then frugally uses this harnessed energy in combination with your Atkinson Cycle Engine (ICE) to expertly scoot you along on the roads ahead, primarily ensuring that wherever possible, your exhaust emissions are minimal - and by extension, you’re burning as little fuel as possible - it does really work, and I’d credit it for my good mpg on my 200 miles of motorway driving to the Eastbourne coast and back - at 70 mph (true GPS speed) showing as 77mph on my speedometer.

Even at that speed, I’ve seen the MFD showing the engine seemingly offline (it’s spinning but using zero fuel) and only the electric motors seem to be powering the vehicle - usually on a very long shallow downward slope.

Other secrets are having a very light foot in urban traffic. Get up to the speed you want quickly (yes, I do jackrabbit starts - 67hp of electric motor assistance flings me ahead of the pack from the lights), then once at the speed limit I invoke cruise control. Otherwise, once you’re at your chosen speed limit, caress that throttle pedal. Shockingly, it rarely needs to be constantly mashed like a conventional car. A light caressing and it keeps up comfortably with the traffic.

Exploit downward slopes to the max. Speed up if safe or otherwise use regeneration to slurp free energy from the downward dive. Never race from red light to red light. You CAN move quickly while invoking Pulse and Glide Protocols - or at least elements of it.

Don’t forget; the throttle pedal has a position very useful for gliding, especially in favourable conditions; whereby you can exploit a shallow downslope by building up speed at up to 43mph without using the ICE or the Electric motor. No power feeds on the MFD, and you’re picking up speed - or at least holding it - travelling along for nothing, using momentum and exploiting a slope (depending on a favourable gradient of course).

You can build momentum from one Hill to get halfway up the next, before employing your ICE - I’ve learnt to exploit two underpass tunnels on my morning commute - I get through them with my mpg being as high as from 72mpg to 99mpg on exit from the underpass. It takes time and practice, but it’s possible - these are Jedi tricks only the Prius can do.

Every little helps; every little saving counts.


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I recently hought a 2008 Touring. It's got 128K miles. The car gets 38.4 mpg, after new tires, cleaned MAS, new air filter & cabin filter. I know I still have more tune-up to accomplish.

The one item that is a puzzle, Torque Pro reports one O2 sensor as a fail. I cantc find much about this sensor, or even if applies to the car. All othet checks in Torque get a green check, except that one. At this time I don't know if this sensor is a contributor to the refuced mpg.

 

Bad O2 sensor will definitely contribute to reduced fuel economy and is probably the biggest contributor in your case. That sensor is part of the feedback loop for the engine management system. It helps determine fuel trim for combustion. I would look into it as a priority before doing anything else. Other than that spark plugs are another low hanging fruit, but none of the basic maintenance items will have a huge effect in the fuel economy. A faulty oxigen sensor, on the other hand can make a night and day difference.

 

Yes, my GEN 2 has 125000 and average 45mpg +. A little highway, mostly local arteries, and even foothills.