When we ran the story on modifying the Honda Insight’s TPS signal, I knew that we’d get some attention. That’s in part because to a much greater degree than with the Toyota Prius, Insight owners – especially in the US – are much more likely to modify their cars.

But what I hadn’t counted on was the stupidity that’s so rampant in car discussion groups. Just as occurred when I wrote about upgrading the Insight’s rear springs to improve load carrying and handling (see this blog), all the idiots came out of the woodwork.

Examples? Try these:

Just my opinion but the circuit does not extend lean-burn, it just helps those with a heavy foot maintain a smoother TPS input into the ECU and the Insight will not drop out nearly as quickly.

Well, no kidding – that’s exactly what the article says the modification achieves!

He was driving pretty fast and I get better results with just my foot.

I was doing the same speeds as other traffic, 80, 100, 110 km/h – what do you normally do, dawdle along in the slow lane?

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Unusually, in this blog I want to refer you all to the AutoSpeed article that was published today. As I have written above, I think it’s probably the most important article that we’ll publish this year.

So what’s it about?

In short, the article is based on a paper written by Dr Andrew Simpson when he was working for the Sustainable Energy Group at the University of Queensland. His paper looks at a huge number of alternative fuels and drivelines, concluding which are the best from both energy efficiency and greenhouse gas emissions perspectives.

Andrew has given us permission to use major excerpts of the paper, and in fact went through it again to ensure that his conclusions are current. The full paper can be downloaded from the link at the end of the article.

His is a detailed ‘well-to-wheel’ study, where the environmental costs of producing the fuel and the efficiency of the cars using them are evaluated. Even better, they’re all benchmarked against a real car, the Holden Commodore. Even better again, the alternative fuelled cars are modelled to have the same range and performance as the Commodore.

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While car modifiers talk endlessly about exhaust systems, there is surprisingly little hard information about the design of exhausts, especially mufflers.

That’s why I was particularly interested to come across the text that follows, contained in – of all things – a book on corrosion of cars, published exactly 50 years ago. The chapter, by H. Silman of Electro-Chemical Engineering, is a great summary of exhaust muffler design.

The automobile exhaust system consists essentially of three parts:

(1) the exhaust manifold, which collects the discharged gases from the exhaust ports and conveys them by means of a pipe at least one-quarter of the diameter of the cylinder to the silencer,

(2)  the silencer, and

(3)  the tail pipe, which leads the gases to the rear, the side, or more rarely to the top of the vehicle.

Sometimes twin parallel exhaust systems are used, especially with multi-cylinder engines, whilst it is also becoming increasingly common for two silencers in series to be fitted, the second and shorter unit being located immediately before the final outlet.

The exhaust gases leave the cylinders of an automobile engine at a pressure of around 60-80 lb. per sq. in. and with a velocity of up to 150 ft. per sec. This results in a considerable volume of noise, which must be reduced sufficiently to make the vehicle inoffensive to the driver and passengers, and to the public at large. This legal requirement is achieved by allowing the gases to expand into a silencer chamber, where the intermittent and violent discharges of gas are broken up and emerge from the tail pipe as a continuous and relatively uninterrupted stream.

There are various designs of silencer, but they usually contain a number of baffles carefully designed to avoid excessive back pressure, which might result in a loss of power and overheating of the engine. There is always some loss of power resulting from the use of a silencer, but this need not exceed about 3% with a well-designed unit.

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Most cars that I have owned have had tow-bars – if they’re not on the car when I buy them, I have them fitted.

So the EF Falcon and Lexus LS400 both had towbars. And, as you’d expect with those cars’ mass and power, both towed very well. On one occasion the Lexus towed a camper trailer, and it very often towed my 6×4 steel trailer. The Falcon towed the 6×4 and once a car-carrying trailer (loaded with a large work bench frame).

So when both of those cars had gone to new owners and I bought the Peugeot 405 diesel, I was pleased to see it had a towbar.

I didn’t – and don’t – expect to be towing big trailers; instead, my 6×4 will be the one usually hung on the back. Trips to the local tip, trips to pick up furniture, carrying around recumbent trikes – things like that.

But as a tow-car, the low-powered and light Peugeot is a very different kettle of fish to the Lexus and Falcon. For starters, the lack of ultra-low rpm torque (when the 1.9 litre diesel is yet to come on boost) makes it very hard to climb my very steep driveway with the trailer on the back. In fact, to do this, I need to thoroughly warm the engine and launch with a lunge at the slope. 

Once on boost, the mass of the trailer doesn’t cause much of a problem; performance is clearly down but with decent driving, it’s no drama.

But one aspect of the Peugeot as a tow car amazes me. And what’s that?

The fuel consumption!

The presence of the trailer makes a radical difference to have much diesel the Pug drinks. Even with the trailer empty, consumption is up by 20 – 30 per cent. One reason for this is that the trailer adds about 25 per cent to the mass; another reason is that the trailer is much less hidden in the aerodynamic wake of the smaller car.

Clearly the idea that towing a trailer increases fuel consumption is not something new.

However, as more people drive cars like hybrids (incidentally, no Prius is factory certified for a tow bar) and smaller engine diesels, trailers designed with more than utilitarian cheapness may become attractive. A smaller, light-weight and aero-shaped trailer would, I’m sure, make far less difference to the Peugeot’s towing fuel consumption…

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A while ago I attended an electric car show held in Sydney. I made the 2000-odd kilometre trip in my Peugeot 405 diesel, a car that, incidentally, gained high Fives (in litres/100km) for the trip.

At the show I briefly sampled three of the home-converted electric cars – a very interesting experience. And on the long drive home to the Gold Coast, I had plenty of time to reflect on these cars.

The electric cars I drove each retained the original gearbox: the electric motor was bolted up to the ‘box and the ratios could be selected by the driver. Typically, the cars were started off in second gear and then third and fourth and fifth gears were used as appropriate. (I used first gear off the line and felt an immediate gain in starting performance.)

But none of the cars I drove had performance that came close to conventional petrol engine (or even commercial hybrids). Even when the electric motor was rated at a higher power than the original engine, the massive weight of batteries substantially dulled the resulting power/weight ratio.

Putting in a more powerful electric motor (or running two electric motors) would of course help solve that, but at the expense of greater electrical power consumption that in turn would need either more batteries or result in a shorter range (and none of the ranges were very good to start with!). However, all the cars could easily exceed the 110 km/h open-road speed limit.

Clearly, what is needed is an electric motor that has only enough power to do the job – but no more.

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Last weekend I attended an electric car show. Organised by the Sydney branch of the Australian Electric Vehicle Association, it was unlike any other car show I’ve ever been to.

Why?

Well, firstly, the cars were different to 99 per cent of vehicles on the road. With the exception of a few current model Prius Toyotas, they were all home-converted battery electric vehicles. That’s right, (mostly) road-registered and street driven, these cars never visited petrol stations but instead needed only to be plugged into mains power.

Another thing rather different about the show was the interest being shown by visitors.

At a typical car sow you’ll get lots of lookers but few talkers. Here, every visitor had dozens of questions – and some even came equipped with notebooks and were writing down the answers. One guy had come all the way from Canberra and was actively seeking the information to enable him to have a car converted to electric power for his daily commute.

Others were asking about conversion costs, battery life, range, performance – and everything else you could imagine.

There was a constant buzz of interested conversation.

Along with the road-registered cars, there was also an electric kart, a half-built electric clubman and an electric motorbike. The road vehicles included a Camry wagon, Daihatsu Charade, Hyundai Excel, Daewoo Lanos and even a Mazda ute.

I was attending the show to gather material for some AutoSpeed stories, and got to drive three of the cars. We’ll be running these stories in due course, but in the mean time, if you’re at all interested in building your own battery electric car – or having a car converted to battery electric power – be aware that there’s a bunch of very enthusiastic and helpful people available to you as a resource.

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A class in the recently completed Darwin – Adelaide World Solar Challenge was designed to showcase commercially available vehicles. The Greenfleet Technology Class had seven vehicles: Audi A3 Sportback diesel, Hyundai i30 diesel, Toyota Prius Hybrid, two Peugeot 207 diesels, Puegeot 307 diesel and a Smart ForTwo petrol.

The fuel economy figures for the event are now in, and the Hyundai i30 convincingly won with an average of just 3.2 litres/100km. That’s stunningly good – better than the Smart (4.6 litres/100km) and the Prius (5.6 litres/100km). Second place went to the Audi A3 with 3.3 litres/100km, with the Peugeot 207 (both cars) at 3.9 litres/100 and the 307 at 5.1 litres/100.

But the figures don’t tell the whole story. The Audi and Hyundai were, in the organiser’s words, “driven conservatively by motoring professional[s]” while the other cars were driven in “everyday driving style”.

We’re not told average speeds and even, for example, if the air conditioning was used.

It’s absolutely fair enough that in an event of this type, drivers try to get the utmost economy out of their cars. It’s a competition, and the winners are those with the lowest fuel consumption and greenhouse gas emissions.

But that’s all it is – a fuel consumption competition, held at almost constant throttle on nearly flat roads for thousands of kilometres.

I am all for fuel economy competitions – and would think even better of them if they had challenging real world scenarios like a minimum average speed and a route that spent a lot of time in major cities.

So what to make of these results?

Firstly, you can also be sure that, in typical use, all the cars listed above would be economical.

However, as you’d expect given the competition route, real world open-road consumption would probably be considerably higher than achieved in the Challenge.

And the relativities between the different cars’ consumptions? This is much more likely to be predicted by the official Australian Design Rule 81/01 figures – at least that test is made with identical driving styles and attempts to replicate real world driving use.

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F1 technology being relevant again to road cars? Surely not! An interesting series of press releases:

First application of mechanical ‘kinetic energy recovery system’ with major Formula 1 team

On the 5th June 2007 Torotrak Plc announced a licence agreement with Xtrac Ltd to use Torotrak’s traction drive technology to develop highly efficient and compact continuously variable transmissions (CVTs) for application in a new mechanical kinetic energy recovery systems (KERS) proposed for Formula 1 (F1) motor racing.

Further to this, Torotrak Plc is pleased to confirm that a major F1 racing team has become the first customer for the mechanical KERS system. This F1 team will be supplied with KERS technology through Silverstone based Flybrid Systems LLP, an innovative engineering company focused on research and development of hybrid vehicle technology, who will source Torotrak’s full-toroidal CVTs used in their KERS systems directly from Xtrac Ltd.

Dick Elsy, chief executive at Torotrak, stated: “the rapid movement from concept to application with a significant F1 racing team highlights the benefits of the mechanical KERS system and its ability to contribute to improved performance. This is also a significant step towards acceptance of Torotrak’s technology for use in mainstream road cars to provide improvements in performance, fuel economy and greenhouse gas emissions.”

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It’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’!

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