Response

Innovative Three-Wheeler

I spotted one of these in the scooter shop near my work. I know it's not a car or HPV, but the steering and suspension design is something different!

Just thought you might be interested in case you hadn't seen one before.

Matt King
New Zealand

Happy Audi Owner

Re I hate it I hate it I hate it...

Replaced Lexus SC400 after 11 years and 240,000km (2 bushes, 1 alternator, and 1 hydraulic hose only!!) with 2002 Audi S6. (Recommended by Autospeed no less!). In 6 months, Car died on first big trip 3 weeks after purchase (thermostat), aircon failed, IPod interface won't work (tried several, no way to get stereo minijack into audio system, weird bose unit), faulty brake lines, but the worst thing about it is the SOFTWARE is COMPLETELY BRAIN DEAD. Can't leave windows open a finger width without lights flashing permanently. Can't open windows a fingerwidth without using ignition key to kill power, as once within fingerwidth, software decides that you want window closed, or open!  Much heavier on gas than Lexus (agree 4WD, more oomph etc) Garage laughed at me, they suggest replacement of disk rotors fairly common, as well as prodigious use of pads.

Most disturbing of all, I cannot find an Audi owner who has not had a fair amount of trouble.

Can't get any workshop manuals. Audi treat you like an idiot. Smartly dressed twerp at desk designed to prevent any rational discussion about vehicle.  Merc's are worse, Beemers slightly better, all are terrible compared with JUC or New JC. Porsche, that is an income statement, not a car, don't even think about it. Couldn't find an NSX in NZ, so bring on the Lexus LF-A. The only saving grace of this piece of SH-1T is that Audi pick up the entire maintenance tab for 3 years.

Roger De Salis
New Zealand

Airless Tyres

Have you seen the michelin tyres that dont need air? They look like run flat technology. www.forwardlook.net Came out in 2005 (proto)

Kevin Kissack
Australia

John on Hybrids

Just a note on hybrids:

In general fuel consumption (with the same engine type) is a function of:

1    vehicle weight - energy required to get up to speed = 0.5 x mass x velocity^2. This energy is then lost as heat when the brakes are applied;

2    vehicle weight and tyre factors including tyre pressure - rolling resistance is proportional to vehicle weight;

3    vehicle frontal area - height by width - and shape factor - aerodynamic drag = C x frontal area x velocity^3 (note that at a low speed of 30 km/h aerodynamic drag may only be 3% of total energy use whereas at 100 km/h the aerodynamic energy drag increases to 30% of total - and 37 times more energy in absolute terms)

Most of the efficiency of hybrids comes from three features:

1    the engine runs at optimum efficiency for much more of the time - every engine has a "sweet spot/ area" where the conversion of fuel to energy is maximised; and

2    instead of brakes turning kinetic energy into heat, the electric motor/ generator turns the kinetic energy back into electrical energy stored in a battery; and

3    the engine may be turned off at lights so making a further small saving in consumption.

Hence the difference in fuel consumption is much greatest in urban travel where regenerative braking has a big effect.

Now the Honda Insight versus say the Toyota Prius:

The Insight was a 2 seat vehicle with a width of 1695 mm and height of 1355 mm = 2.23 square metres, and a weight of 838/ 852 kg

The Prius is a 4 seat vehicle with a width of 1725 mm and height of 1490 mm = 2.57 square metres, and a weight of 1325 kg

In city travel the weight is the major issue. Insight at 3.4 litres/100 km  goes to 5.4 litres/100 km pro-rata on weight compared to the Prius 5.1 litres/100 km.

Of course the other issue is engine type - a turbocharged diesel has a basic efficiency of around 40% because of its much higher compression ratio and hence higher peak temperature compared to a petrol engine at around 25%.

John Lambert
Australia