“Normal” fuel economy…

Posted on October 12th, 2007 in Driving Emotion,Economy,Peugeot by Julian Edgar

peugeot-405.jpgIt’s amazing how ‘normal’ is such a flexible term. That idea can be applied as broadly as you wish – normality in society simply depends on majority behaviour, nothing else – but here I’m applying it to fuel consumption.

The main reason I picked a Peugeot 405 diesel as our project car is fuel consumption. Like the hybrid petrol/electric NHW10 Prius that I turbo’d, the Pug has to maintain good fuel economy, even with the performance modifications that I’m doing.

Basically, if it starts to drink like a Commodore, the project’s a failure. [Where oh where is the Commodore diesel?!]

And I am not talking about fuel consumption in some economy run; nope, I’m talking my real-life consumption. Most of my driving is up and down the steep mountain where I live, plus a little urban and a fair serving of freeway.  Over long experience I have realised that this driving regime penalises small engine cars – they have to work really hard climbing the big hill – and so no economical car gets optimal fuel consumption in these conditions. That’s especially the case with the air con running. But that’s where my cars are driven, so it’s the fuel consumption that applies to me.

My hybrid Honda Insight, capable in the right freeway conditions of turning in a real-life 2.8 litres/100km, gets in the high Threes / Low Fours in my normal use. The turbo Prius, off the road now with a defective high voltage battery, got in the mid-Sixes.

Frank the now departed modified EF Falcon, got in the mid-Tens to low-Elevens and my standard Lexus LS400 (also now departed) got similar consumption.

And the Peugeot? The first tank, with the car driven on my local roads, yielded a measured economy of 6.9 litres/100km.

A 700-odd kilometre country drive, two adults, one child and a fair amount of luggage resulted in 5.7 litres/100km.

Another tank involved lots of performance testing, dyno runs, draining of fuel from the filter to remove water, and up and down the hill and some freeway work. The result was 7.0 litres/100km.

Now these results are pretty damn’ good. The Pug, while certainly no performance demon, is a comfortable car with room for four, a big boot, very good air conditioning (in fact, with the heavily tinted windows, amongst the best air conditioning systems of any car I’ve ever driven!), and – most critically – it cost only AUD$6900 to buy. (Even the cheapest hybrid is roughly twice the dollars.)

But today when I punched the calculator’s buttons to work out the consumption of the most recent tank, I was rather disappointed. After a whole bunch of mods (which we’ll detail in due course in AutoSpeed), mods which have revolutionised on-road performance, I saw the fuel consumption number and felt a bit miserable.

Yes, the tank might have included towing a 6×4 trailer loaded with two large bookcases – the aero drag on the freeway was like a giant hand pulling the Peugeot back! 

Yes, it also included the climb up the hill with the trailer, air con running and two adults and a child in the car; the 1.9 litre Pug was certainly working hard. (I’d love to know how hot the intercooler got!) And the air con was running for basically the whole time this tank of fuel was being consumed.

So 6.6 litres/100km is actually quite fantastic: but when I saw the digital numbers, I was disappointed. That’s what looking at the Honda Insight’s fuel economy read-out does to you… it changes your definition of ‘normal’!

2 Responses to '“Normal” fuel economy…'

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  1. Jase said,

    on October 12th, 2007 at 8:15 am

    Good one Julian.

    My previous drive was a BA XR8 Ute where the best was 11.7l/100km on an a flat country highway on cruise with the air-con off. We also had a non turbo Saab 9000 that did about 8l/100km along the same stretch.

    Now I drive a Saab 9-3 Sportcombi auto and it does about 7l/100km under the same circumstances. A good indicator of achievable economy was 7.4l/100km on a 130km round trip to Melb Airport with luggage and passengers.

    Now I am doing 40,000km a year and getting an average of 8.6l/100km and finding that too high. Am looking at going the Saab 1.9TiD next year and expect to be averaging just over 6.

    Funny how “normal” changes. Could not even consider any of the local product now as fuel usage is just not acceptable any more.

  2. Philip Armbruster said,

    on October 12th, 2007 at 9:57 am

    What sort of performance penalties are you willing to trade for economy?
    Its amazing to me that my 1995 BMW M3 3.0 litre posted 8 litres per 100Km on a trip from Sydney to The Gold Coast and back on the Pacific highway with all its hills and slow towns. Just before Coffs it was down to 7.9 and that was cruising at a real”GPS checked” 115 in 110 zones .
    It seems to me that the diesel Peugeot will always be a “turd” no matter how much you polish it, and Priuses have the potential when old to be disasters, let alone the fact that they are one of the most environmentally unfriendly cars on the road or off. Julian What did you do with all those nicad batteries?
    The future as espoused by Fiat is with efficient petrol engines, as hitech diesels are too expensive to produce for the mass market. Fiat are the most advanced and successful small diesel manufacturers in the World.
    Regards Philip A

  3. Julian Edgar said,

    on October 12th, 2007 at 10:55 am

    The ‘turd’ would have been able to maintain the same speed as you did from Sydney to the Gold Coast and back – and use far less fuel. In fact, probably near 40 per cent less fuel. So, in the example you chose to cite, what is the point of your car’s performance?

    What ni-cad batteries?

    What ‘expensive’ diesels?

  4. Marty said,

    on October 12th, 2007 at 11:57 am

    everyones perspective on this will surely be different! i went from a fast, well handling, comfortable, turbo jap import wagon to a front wheel drive, 1.3l nissan micra – what a difference!

    i sacrificed alot of the above but get some satisfaction when the service station pump clicks off at $40 to fill it, and also knowing its impacting the environment alot less

    not sure if this comes into your mind alot, i don’t consider myself much of a hippy, but the black smoke spewing out the back of the GT seems kinda unnecessary

  5. Mick said,

    on October 12th, 2007 at 2:03 pm

    We always seem to be a lot more conscious of the fuel bill ’cause it hurts every week or so coming out of our wallet. My wife drives a VR V8 Statesman that drinks like a fish running the kids to school and the numerous shopping trips. The car averages 16,000km per year, that includes some country driving (not a lot – mostly the work truck towing the boat for country runs – fuel consumption of both, don’t ask…)

    The statesman’s annual costs still average 55% rego, ins, repairs and maintenance to 45% fuel. That excludes the value that has haemorrhaged (sp?) on it purchase price 9 years ago.

    Despite the outrageous price we have to pay for fuel, it remains one of the lesser costs to running a car. Although I really enjoy reading about Julian’s projects, return on investment would be a rather subjective evaluation.

    The mods on Frank for example, resulted in better performance, handling, braking and fuel efficiency. Were the savings in fuel consumption offset by tyre wear? The value added to the “driving experience” is intangible, but since we’re talking fuel efficiency, what is the payback period in km for the various mods?

  6. Julian Edgar said,

    on October 12th, 2007 at 2:21 pm

    Mick, four points.

    Firstly, the Falcon wasn’t modified specifically to gain fuel economy. I just didn’t want it to go backwards with the improved performance.

    Secondly, very few people modify a car for fuel economy because it’s simply so much harder than improving power. Any workshop can improve power. Ask them to improve economy and…

    Thirdly, the Peugeot diesel (yeah, I know, the first article isn’t scheduled for a month…) has been modified radically cheaply. In fact, under $300 (including tuning fuel) for all the work so far performed. Aagin the mods have improved economy as well as giving much improved performance.

    Fourthly, I have never – and will never – use $ payback time as a deciding assessment of fuel economy comparisons. Sorry, but to me that sems very ‘Nineties’, where societal and personal cost and benefits are assessed in purely dollars terms. I don’t own the Honda Insight because of its lower weekly fuel bill.

  7. Philip Armbruster said,

    on October 12th, 2007 at 2:57 pm

    Julian, I guess your response illustrates my point.
    Its hard to improve economy of a petrol engine.
    So this is surely where the mag should be concentrating.
    And improving economy is socially responsible, and not contradictory with improved performance.
    IMHO Diesel and hybrids will always be in the tiny minority in Australia. Now you may have joined the evangelists, but I was pointing out that maybe the Peugeot is relevant to hardly anybody. How many were sold in Australia ?10?
    I suggested ealier that you look at updating fuel injection on older cars as a project.
    I have just fitted o2 sensors to my 92 range Rover after finding that the UCU had the circuitry. So far and admittedly only one tank, I have gained 22% economy. Even with the worst filling errors it is over 10%. This is an outrageous result , and I fear there must have been some programming error in my Unichip, which is now overidden by the sensors.

    Where are the articles on fitting an ECU with wide band O2 sensors and lean cruise, to improve what MOST of the readers are concerned with.ie the economy of their WRX, Falcon, Commodore or whatever.
    I included the reference to Fiat as they are the World leaders in small diesels, and even they do not think diesels have a bright future vs updated petrol engines, in small cars.
    And I was baiting you on the batteries. I am sure you know very well of the US study that looked at whole of life environmental cost of a Prius, and concluded it was the worst car of all for the environment. I have seen several emotional attacks on the results but no facts yet that dispute their findings.
    Regards Philip A

  8. Julian Edgar said,

    on October 12th, 2007 at 3:23 pm

    “I have seen several emotional attacks on the results but no facts yet that dispute their findings.”

    You haven’t looked very hard then Philip. Just compare the figures the study used of the lifetime kilometres of the Hummer and the Prius to see how weird the findings were.

    Diesels make up over half of all new cars sold in Europe. I haven’t got any figures, but the growth rate in diesel sales in Australia in the last year has been astonishing. To say that diesels will always be a tiny minority in Australia is certainly a big call indeed.

    The EF Falcon was the largely the exception to the type of cars that I’ve written about. I tend NOT to write about mainstream cars. How many 5 cyl Audi S4s were sold in Australia? How many Daihatsu Handi turbos? How many NHW10 Prius? Is the Austin 1800 a popular collectable? etc

    I don’t really understand your point about fuel economy. Yes it’s hard to improve the economy of a car. Yes we did it on the Falcon. Yes we did it on the Prius (in some conditions, eg freeway, anyway). Yes we did it on the upcoming Peugeot series. It hasn’t yet been covered in AutoSpeed but I think I have improved it a little on the Insight too.

    What factory management system after 1986 doesn’t have oxygen sensors? In a road car you’re now mad to ditch the factory system, so it would be pretty weird to cover fitting oxygen sensors to cars, wouldn’t it?

    I have been thinking about an aftermarket lean cruise mode for years, but enacting it is rather harder than it first appears.

    The Prius doesn’t use ni-cad batteries. My point is that you don’t appear to have much knowledge about what you’re saying in regard to hybrids. Getting the battery type right is pretty fundamental.

    Finally, where’s this refence to Fiat you keep mentioning? I’d like to see it and see exactly what was said. (It’s emissions performance that is likely to hold back diesels, not fuel consumption.)

  9. Lindsay said,

    on October 15th, 2007 at 6:16 am

    I have only just picked up this blog entry and have read over much of what has been said…

    One point I have to agree with wholeheartedly is Julian’s comment on the (seemingly exclusive) use of dollar paybacks to make decision.
    I feel that all to often people are make terms purely on a dollar or dollar payback decision. People need to start looking at choices from a perspective other than dollar payback. There needs to be some realisation that societal needs cannot be measured wholely that way.

    I also like the way that fuel economy is being measure, monitored, and compared based upon a normally daily routine.

  10. Andrew said,

    on October 15th, 2007 at 11:35 am

    Without an effective system for enforcing/encouraging such decisions it is a matter for each individual’s conscience but, unfortunately, effectively all you are doing is making it easier (cheaper) for those who don’t care.

    After some consideration, my view is: do whatever is best for yourself, without being profligate, and vote for those who will introduce legislation that results in individual costs for all that better reflect the true societal costs.

  11. OttoAu said,

    on October 15th, 2007 at 11:50 am

    The economy king without any doubt is haonda.
    Look back and see a test on a Civic Vei, when THRASHED the *worst* they could do was 5%
    If you really tried you could get it into the 3’s…
    honda discontinued it as no market, for sure now it would find a market…

    For the rest of us, you CANNOT beat LPG.Period

    Cheers O/A

  12. OttoAu said,

    on October 15th, 2007 at 12:09 pm

    I drive a Diesel van ATM, Diesel is NOT the holy-grail.
    Very expensive fue {+10% ULP/ around TRIPLE LPG in Vic.] together with the extra +10-15% extra purchase price, filthy and dirt fuel bowsers and concrete, smell, NVH, pure yuk…PASS
    LPG is Aussie made, $2k from Howard.
    Less than 4cyl running cost for a large 6, CANNOT be beat.
    Cheapest running costs in the world, follow taxis = LPG
    DIEsel id for Europe not us

  13. Richard said,

    on October 15th, 2007 at 1:24 pm

    OttoAu, the trouble with LPG at present is that people run it simply based on running costs.

    From all accounts it has no real benefits, C02-wise, over a similar petrol vehicle. If you believe in C02 reduction then LPG is effectively a dead end.

    Lindsay said..”I feel that all to often people are make terms purely on a dollar or dollar payback decision.”

    Less fuel used = less money spent = less emissions. What’s wrong with that equation?

    Buying secondhand = less money spent = less pollution building a new car!

    Buying a smaller new car = less money spent than buying a big car = less raw materials consumed.

    Maybe I am missing the point. To reduce pollution and fuel usage the easiest method would be to RAISE fuel prices. The manufacturers would rush economical cars to the market. This was seen once before in the 70s during the oil crisis.

  14. Frugal-One said,

    on October 15th, 2007 at 10:09 pm


  15. Lindsay said,

    on October 17th, 2007 at 5:57 am

    (I really should check back more often)

    Richard Said:
    Lindsay said..”I feel that all to often people are make terms purely on a dollar or dollar payback decision.”

    Less fuel used = less money spent = less emissions. What’s wrong with that equation?

    Buying secondhand = less money spent = less pollution building a new car!

    Buying a smaller new car = less money spent than buying a big car = less raw materials consumed.

    There’s nothing wrong with your logic.
    Take, for example, my folks (typical for the example). When looking at a new car I urged them to consider a Prius. Here is a mid/ to large size family car. It can take four people, plus gear and transport them around town for better than 16km/L. But brand new they cost around $46k.
    Compare that to a corolla wagon. mid sized family wagon that can transport four people plus gear for around 12km/L and cost $23k (on special).
    Both cars would be 90% city driving.
    On paper, from a dollar point of view the corolla is the no brainer. It would take a considerable number of kilometres to make up the price difference.
    And that’s how my parents looked at it. They ignored the fact that (given their driving habits) the prius would probably produce between 10-20% of the emission of the corolla.

    Buying second hand is another personal gripe. Most people buy old second hand. They don’t get the benefits of the much more modern technologies, and therefore continue to “harm” the environment more than they need to. All because it’s hard to justify spending more money.

    I just feel that becuase it’s hard to dollarise, people don’t account for the environmental aspects of any purchase. What is the dollar value of reduced emissions from a vehicle? What is the dollar value of reducing mains supply (water or power) loading (as compared to the reduction in consumption which is easily dollarised)?

  16. Mark Eckas said,

    on December 7th, 2007 at 8:02 am

    Some real world figures from a Mazda 6 Turbodiesel Wagon.

    Worst: 8.4 l/100km over a 2000km trip towing an enclosed trailer from Wollongong to the gold coast and back, fully loaded car with a roof pod on top
    Average over 35,000 km of motoring: 7.1l/100km.
    Typical Highway Trip: 5.6l/100km over a recent 1007 km trip from Wollongong to Dubbo to Sydney to Wollongong.
    Best: 3.9 l/100km on an ultra-economical, a/c off, 95km/hr cruise from North to South down the length of the M7 (40km) in Sydney.

    I find accurately described, real world fuel consumption figures far more revealing than the std test cycles.