Weight and per person fuel consumption

Posted on June 2nd, 2007 in Opinion by Julian Edgar

2591_7mg.jpgAny vehicle designed to transport people must move two masses – the mass of the vehicle itself and the mass of the people and/or goods it is carrying.

So a bicycle, the most efficient means of transporting just one person, has (say) a total mass of 100kg, of which 85kg (so 85 per cent) comprises the load being carried. (A skateboard does even better.) A Holden Calais weighs 1700kg to carry about 450kg – or to carry 21 per cent of the total mass. A Peugeot 206 GTi has a mass of 1050kg and can carry probably about 350kg, or about 25 per cent of the total.

But these are theoretical maxima.

What if there’s just the driver in the Calais? Then the mass being carried is just 4.5 per cent of the total vehicle weight! More than 95 per cent of the weight moving along the highway is not the primary load being transported!

Even in the lightweight Peugeot, a single person aboard will still mean that 93 per cent of the mass being moved is not the load.

Rear wheel drive can be dangerous

Posted on May 19th, 2007 in Handling,Opinion,Suspension by Julian Edgar

108569_7mg.jpgI think this (apparently uniquely Australian) idea that big family cars need to be rear wheel drive is simply rubbish. You hear it all the time – rear wheel drive is best for towing, rear wheel drive is best for handling, rear wheel drive is somehow hugely superior over front wheel drive. Well, apparently it is for the macho Australian male, anyway.

From the day I first bought a car I have never been a believer in the philosophy; in the time since I’ve owned rear wheel drive, four wheel drive and front wheel drive cars – and I have remained unconvinced. In fact, if anything, I think I am leaning heavily in the direction that rear wheel drive, without traction control (or better still, stability control) is potentially bloody dangerous.

Today is a perfect example. I’d bought a big workbench on eBay – and this morning I had to go pick it up. The thing is enormous – much too big to fit on my normal 6 x 4 trailer. So I organised the hire of a car carrying trailer. When the alarm went off at 5.45 am (pick-up was set for 8 am) I awoke, listened for a moment, and then my heart sank.

It was raining.

I needed to go down the narrow, tortuous road from the mountain on which I live, pick up the huge trailer, then drive straight back up the mountain, descending the other side on an even tighter, narrower road. All in Frank the EF Falcon, a car which even without a trailer hooked on the back, power oversteers around these wet and slippery corners even when you’re trying to drive gently. Perhaps it’s the tyres – and the rears are certainly down in tread although still quite legal – or perhaps it’s the sheer torque and throttle response of the 5-speed manual Falc. But either way, it’s a car that in the wet needs to be treated with an incredibly judicious right foot. Even when you’re not towing a huge trailer with a 300kg workbench strapped to it.

AutoSpeed changes…

Posted on May 5th, 2007 in Opinion by Julian Edgar

Back in November 2006 we foreshadowed some major changes to AutoSpeed.

We said that there’d be more DIY hands-on tech. There’d be more stories on the background engineering of cars and their technology. We said we’d be driving more cars – both new and used – and we’d be doing less stories on modified cars high on bling and nothing else. We said we’d be modifying a mainstream and cheap project car – an EF Falcon six cylinder – and we’d be adding instant reader voting for each story. Finally, we said we’d be re-presenting previously run stories, primarily because the vast majority of current readers had never seen them (and in return, we were extending current subscriber periods to take into account the reduced new content).

And, with one exception, we’ve done all of that. We’ve run more hands-on stuff; we’ve run heaps of background stories on car engineering; we’ve covered the Falcon modifications including brakes, extractors, exhaust, cam, engine management, air intake – and now we’re doing the suspension. All nitty gritty, real world stuff, photographed in huge detail.

And the exception? We’ve driven less cars than I wanted to.

The announcement of change was greeted with near universal acclaim by you, our readers. And those changes have been very successful at bringing new readers to AutoSpeed – compared with October last year, last month our visits were up by 16 per cent and our page views increased by a whopping 31 per cent.

Real world family car driving

Posted on April 21st, 2007 in Mitsubishi,Opinion by Julian Edgar

2960_6mg.jpgIt seems like only yesterday that the Mitsubishi 380 was released, but time is no friend to a car company – not when the Toyota Aurion and VE Holden Commodore have both since seen the light of day. Throw in the still highly competitive Ford Falcon and the pretty-well-just-as-big-inside Toyota Camry – and of course the highly impressive Hyundai Sonata V6 – and you have what can only be called a very difficult market for the Mitsi. Not to mention the fact that public uncertainty over the future of the local manufacturing plant has assumed almost TV soap opera proportions…

The result is not unexpected: at the time of writing, you can buy a Mitsubishi 380 with less than 10,000km on the clock for under AUD$24,000. Expect that to soon dip below $20K – and for a fearful rate of depreciation to follow. To put this another way, if you expect to keep a car for a long time (say 10 years), you can now step into a fast, excellently handling, and near new family car for what can only be described as an astonishing bargain price. Well, that’s what I think the car is.

But what’s it actually like in a family role, child seat in the back and mostly doing the humdrum duties of urban travel and shopping centres, with just an occasional longer country trip thrown in? My wife, Georgina, recently spent three weeks in a 380 ES 5-speed auto, a car with 30,000km on the clock. She drove the car with Alexander, 2, in the back. Georgina normally drives a Toyota Prius and has driven the current Sonata, Falcon, Commodore, the last of the Magnas, and many other cars.

Here are her comments.

Julian Edgar

An article that rated badly

Posted on April 7th, 2007 in Opinion by Julian Edgar

107829_4mg.jpgAs most of you would know, we now have an instant reader feedback facility for every article. The system, which appears only for AutoSpeed subscribers, allows you to vote on a 1 – 5 scale, with ‘1’ at the bottom of the barrel and ‘5’ at the top.

On most days I look at the results once or twice – obviously not for every article but for the most recent. In general, the scores pretty well match what I expect. That’s not to say I can predict the results perfectly, but I knew that John’s Jet would be popular (it’s our highest rating article ever) and that, for example, Negative Boost Revisited, Part 1 would be relatively unpopular (cos it’s the first in a long series, and is for many people, just background material).

Subscriber article ratings that have really surprised me by how high they rate are mostly those to do with hybrids – Prius vs Insight and Diesel Hybrid! are two.

Of course (or perhaps not of course: I have been looking at readership stats for a long time), external readership numbers are often completely out of keeping with subscriber ratings; to bring new readers to AutoSpeed as well as keep current readers relatively happy, I need to keep a weather eye on both sets of data.

But one article that has really concerned me in its subscriber rating is How Heavy’s Your Knob?. As I have mentioned before, I thought this article was a really good one. Why? Well (1) it covered a modification technique I have never seen mentioned elsewhere; (2) it was very cheap; (3) it was very easy; (4) it was very effective.

Power to move

Posted on March 24th, 2007 in Opinion,Power by Julian Edgar

108228_2mg.jpgThe other day when I had Frank the EF Falcon on the ChipTorque dyno, I did something pretty interesting. But first, some background.

I’ve installed in the Falcon the trip computer that’s normally fitted to higher trim models. It displays all the usual trip computer stuff – average fuel economy, average speed, and so on. It also displays instantaneous fuel consumption.

From watching this display a lot, I know that at an indicated 110 km/h on a level freeway (actually 105 km/h when a speedo correction is applied), the instantaneous fuel consumption figure fluctuates between 7 and 8 litres/100 km. (Unfortunately, the instantaneous display doesn’t have any decimal places.) Over a long distance in these conditions, the average is 7.5 litres/100 – so that instantaneous number makes sense.

On the dyno it was easy to dial up an indicated 110 km/h and then increase the load until the instantaneous consumption figure was fluctuating between 7-8 kilometres/100. Then it was just a case of reading off the dyno screen how much power was being absorbed at the wheels. The answer was 13kW.

So, in the Falcon, it takes 13kW to propel the car along level ground at an actual speed of 105 km/h.

Going the wrong way in the ride/handling compromise

Posted on March 10th, 2007 in Handling,Opinion,Suspension by Julian Edgar

Click for larger image There are a few ways of regarding the comments I am about to write. One perspective is that they’re the ramblings of an old, out of touch man who prefers comfort to handling. Another is that I am stuck in the past, ignoring the advances that are self-evident – well, to all but apparently me.

But I think that most car manufacturers are on the wrong track with their current ride/handling compromise.

Having a car that handles competently is important. No one wants to see people spear off the road when they make a minor error; no one wants to see new cars being sold that squeal and wail and wallow their way around corners. But the opposite extreme – cars that are built to handle road conditions and driving behaviour that nearly all will simply never see – is almost as silly. Why? Well, every time you’re in a car, you’re being subjected to its ride – whether that’s good, bad or awful. And while it may be possible to produce cars that both handle and ride well, in the vast majority of production cars, better handling means a worse ride.

Engineering innovation that leaves modified cars for dead

Posted on February 24th, 2007 in Opinion by Julian Edgar

Click for larger image

I know that this is a car publication – and primarily a modified car publication – but forgive me if I digress.

As we’ve been covering in our series Building a Human Powered Vehicle, I have been making a recumbent trike. That is, a three wheeled, pedal-powered vehicle where the rider lies back at an angle and the pedals are relatively high up in front. My design uses full suspension (front double wishbones, front sway bar, rear trailing arm), is made from aluminium and uses a rear damper. It was inspired by the non-suspension Greenspeed series of trikes, of which I own one – the Greenspeed GTR.

Before building the trike, I knew very little about them – and very little about bicycle design as well. So, you might be thinking – what is there to know about bike design? Well, lots and lots. Things like gearing (crank length, front and rear cog sizes, gear ratios), steering (trail, castor), and of course frame design. With tadpole trikes, you can also add scrub radius, toe and Ackermann, and with a suspended trike, static and dynamic camber, anti-dive and so on.

Home builders of bikes and trikes have an extensive web presence, and while there are some simply horrible designs prominent, there are also some excellent engineering pages devoted to design. In fact, when I compare this scene with modified cars, in terms of uniqueness, engineering innovation and results, recumbent bikes and trikes show far more progressiveness than home builders and modifiers of cars. (The only home-built transport application which I think is even better can be found in experimental class aircraft.) Small, specialist engineering companies are also prominent in recumbent trike building.

Enough of the generalities – let’s look at a specific case.

How the Web quells innovation

Posted on January 27th, 2007 in Opinion by Julian Edgar

One aspect of the Web which is seldom acknowledged is that it can stifle creativity and development. Huh? But isn’t the Web a place that encourages self-expression, allowing free reign of ideas that were once suppressed? Well, kind of. The trouble is that anyone with an innovative approach (that is, by definition one that has not been widely adopted previously) is likely to be ridiculed for it; to be told that it won’t work.

I’ve seen this happen in car modification many times, and in fact twice just this week.

Both were in discussion groups: that frequent scourge of progress. The first was in a Porsche discussion group. As I have said before, I don’t regularly read many discussion groups but I still get to see a lot by reading the AutoSpeed referrers’ listing. This listing shows the web pages that readers of our articles have come from – and these are often discussion groups. Someone in the Porsche group referenced one of our articles on the over-boost canister (see Killing Wastegate Creep) and asked if this would work on Porsches.

All the answers were negative: nope, it wouldn’t work; it was just like another type of boost control; it would cause boost spikes (duh!); it was of no benefit. Firstly, few if any of the respondents had actually read the article in any detail. Secondly, none (not one!) understood the purpose of the approach. And thirdly, the use of an over-boost canister will of course work on any turbo car – and its affect can be easily adjusted to suit personal preference or turbo/engine characteristics.

But the original poster gained from the group responses the idea that the approach was of no benefit.

A Rocky trip

Posted on January 13th, 2007 in Economy,Honda,Hybrid Power,Opinion by Julian Edgar

I write this after completing two 750-kilometre drives, each done in a day. The occasion was the wedding of some friends, and the location was the Rydges resort at Yeppoon, on the coast near Rockhampton in Queensland. My wife and son flew up from the Gold Coast where we live; I decided to drive.

The car was my 1-litre, three cylinder hybrid Honda Insight. But isn’t that a long drive for a little car? Perhaps – but so what? There’s plenty of cabin space (in fact, with the seat adjusted correctly, my left foot can barely reach the firewall) and I don’t have any problems with driving a low-powered car on the open road. In this era of very powerful base model Australian cars, people tend to forget that safety on the highway is much more dependent on driving skill than the acceleration available under the right foot. I didn’t have any problems overtaking a few semi-trailers or climbing hills at the speed limit – and I saw lots of very powerful cars that had near misses, simply through appalling driving.

The only changes I made to the car for the trip were to inflate the tyres to 37 psi (hot) and fill the tank with 98 octane fuel. I think as a result of one or both of these, fuel economy was even better than standard. Well, it would have been if I hadn’t run the air con for about 80 per cent of the time….

After resetting the trip computer fuel economy display at home, my first stop (the petrol station to fill the tank) showed a fuel economy of 2.2 litres/100km (most of the trip to the petrol station is downhill), followed by 2.7 litres/100km at the Gateway Bridge and 3.2 litres/100km at Gympie. Following that, I turned on the air and the road also became hillier: the consumption average then steadily rose to 3.5 litres/100km where it stayed for the rest of the trip, including the full return journey.

As I have said many times before of this car: that’s world’s best fuel economy.