In-line shaft dyno

Posted on November 27th, 2008 in Driving Emotion,Technologies,testing by Julian Edgar

The other day I bought some manuals published in July 1960. They’re lecture notes from the Technical Training School for Qantas Empire Airways Ltd.

The notes are primarily on the Lockheed Electra, an aircraft powered by four Allison 501-D13 prop jet engines. These engines each developed about 4000hp.

One of the very interesting technologies covered in the manuals is a real-time, on-board dyno. Yes, in the cockpit was a gauge that displayed the power being produced by the engine! This gauge was calibrated from minus 1000hp to plus 6000hp. Accuracy was quoted as being +/- 355hp.

So how was a real-time indication of power output gained?

On this turbo prop design – as with all turbo props that I’m aware of – a gearbox is used to reduce the speed of the turbine to that suitable for driving a propeller. The turbine is joined to the reduction gearbox by means of a driveshaft, splined each end. Surrounding this shaft is another shaft, this one splined only at the turbine end.

Cost vs benefit of car modifications

Posted on November 25th, 2008 in Aerodynamics,Driving Emotion,Economy,Honda,Opinion by Julian Edgar

When modifying cars, everyone conducts some sort of cost/benefit analysis.

That might be as informal as weighing-up the likely cost of the modification against the guessed benefit, or it might be a more detailed analysis.

A friend of mine, Paul, has a rule of thumb that goes like this:

Back in 1998, on naturally aspirated cars, he budgeted $100 per kilowatt for a power improvement. Any more than that and he thought the value poor; any better than that and – well, he thought that was pretty good.

That $/kW ratio was for mods like intake, exhaust and chip.

I don’t want one any more…

Posted on November 20th, 2008 in BMW,Opinion by Julian Edgar


It’s perhaps the only car that I have always wanted – well, from the day of its release, anyway.


The year was 1988 and the BMW 750iL was an astonishing car – twin electronically-controlled throttles, 12 cylinders, a limousine that handled so well that contemporary magazine testers were able to triple advisory speed limit signs around corners. On just six of the twelve cylinders, it could still exceed 200 km/h…


I’ve watched and watched as their prices have fallen – in 1988 the cars were $216,000; each year since they’ve got lower. Now, they’re under $10,000.


Less than ten grand for what was amongst the very fastest of four door cars in the world, a superbly equipped, beautiful looking sedan from that long ago time when BMW styling still had grace and cohesion.

User-adjustment better than factory pre-sets

Posted on November 18th, 2008 in Driving Emotion,Engine Management,Handling,Opinion by Julian Edgar

I’ve been thinking about the way in which cars are heading. More and more these days you see driver-selectable modes. A sports mode – or even super sports mode – on a double clutch transmission. A button that sharpens throttle response, changes damping and alters auto trans shift points.

Two points.

Firstly, if the car drives badly when in standard mode, fitting a special button doesn’t fix the car. The ‘fix’ needs to be far more fundamental: at minimum, all modes need to drive well.

But the main point I want to make is this.

Why on earth are manufacturers giving only ‘digital’ control over this type of driver selection? Why an on/off switch when it would be far better to provide an analog knob that allows the driver to adjust the action of the system to their taste?

A knob for power steering weight.

What an absolutely crap car

Posted on November 13th, 2008 in AutoSpeed,Opinion,Peugeot,Reviews by Julian Edgar

Look, I’ve tried to like it. I’ve admired its quite brilliant fuel economy, and its generally excellent ride/handling compromise. I mean, I was even very positive in the new car test I did on the car when it was first released back in 2003.


And when this family bought one with our own money, it was with the (stated) intention of making it an AutoSpeed project car, in much the same way that we did with the Peugeot 405 SRDT.



But I need to be honest. I just simply hate the Peugeot 307 HDi – I think it’s a car that in many ways is just rubbish.


Now normally to support such a statement you’d have an extensive list of shortcomings in its driving performance. But in fact, the Peugeot largely drives very well.


One clear negative is its dreadful low rpm management mapping and/or turbo sizing: this is one of the deadest off-boost turbo electronic direct injected diesels you can drive, especially in hot weather.


(I just checked the date of my original new car test – published November so probably tested about September. Just on the edges of the Australian summer – but not into it.)


But otherwise, the steering is largely OK (well, it kicks back when driving really hard); the ride is good; the handling is adequate and the brakes fine.

Blowing money out the exhaust?

Posted on November 11th, 2008 in Driving Emotion,Opinion by Julian Edgar

Looking at how astonishingly badly the Australian-manufacturing car companies predicted car buying habits, one wonders if they should be rewarded by being given even more of our money…..

Taming throttles

Posted on November 11th, 2008 in Engine Management,Mitsubishi,Opinion,Turbocharging by Julian Edgar

A while ago in a reply to another blog post, I wrote about the current Lancer Evolution that:


“The Evo should use far improved throttle mapping where blade angle is mapped against foot position and the calculated instantaneous tractive effort value. It should also use a smaller turbo. ”


At least one reader was so excited by this notion that he wished to “quietly roll up into a foetal position and rock back and forth on the floor”. However, leaving aside bizarre responses, it’s a concept sure to interest some.


I won’t discuss the ‘smaller turbo’ bit because most of you will have a good understanding of this idea. But what about the throttle mapping?


In electronic throttle cars, the relationship between the accelerator pedal position and the throttle blade opening no longer needs to be linear. In a linear system, the throttle blade would be half open at 50 per cent accelerator pedal travel, three-quarters open at 75 per cent accelerator pedal travel, and so on.

Initial thoughts on driving the FG Falcon XR6

Posted on November 6th, 2008 in Driving Emotion,Ford,Opinion by Julian Edgar

Day #1, Urban

Power steering heavy, good (apparently variable) ratio, good feel

Suspension gives firmly damped ride

NVH very good

Performance at full throttle nothing special – air con switches off at merest hint of lots of throttle and seems to stay off for a long time (relatively speaking eg 5 secs)

Cabin feels surprisingly enclosing, not spacious – cf colours of trims, width at driver’s knee level poor, distance between back seat and rear of centre console poor

Speedo and tacho have stupidly fussy markings + silly ‘XR6’ colouring

Central instrument panel LCD is model of clarity – good range of selectable options, including digital speedo

I-phone connectivity (including charging) but no on-LCD display of tracks, etc

Around town fuel consumption with air con on – 12.5 – 13.5 litres/100km – this is progress?

Teaching yourself new ideas

Posted on November 6th, 2008 in Driving Emotion,Opinion by Julian Edgar

I make a living doing what I have taught myself to do.


When I first started writing and selling magazine articles – they were about photography – I was writing about a topic on which I was entirely self-taught.


When I started writing articles about modifying cars (and again selling those articles, but this time the ‘selling’ took lots of attempts before it was successful!), I was again writing about a subject on which I was largely self-taught.


My formal qualifications at that time were in teaching; my Bachelor of Education degree has double majors of Geography and Sociology – nothing remotely to do with automotives, mechanical engineering, physics, maths or technology.


Or for that matter, English, journalism or writing.

Air or steel springs – the Porsche Cayenne

Posted on November 4th, 2008 in Driving Emotion,Opinion,Suspension by Julian Edgar

The other day I was given some interesting Porsche books.

From any other car manufacture, they wouldn’t be ‘books’ but instead be new car brochures, but Porsche really do produce full books on their models. (Incidentally, these are always worth buying – a friend who sells them on has the user name q993.)

One of the books was on the Porsche model that I believe to be a complete sell-out of everything that Porsche has always stood for – the 2.2 tonne Cayenne.

(And these thoughts were confirmed when I looked at the car’s quoted fuel economy – a combined cycle of 15.8 litres/100km for the manual Cayenne S. Even the 306 km/h 911 GT3 is quoted at 12.9 litres/100km!)

Anyway, be that as it may, what interested me in the Cayenne publication were the details on the suspension. Two different types of springs are used – air suspension on the Cayenne Turbo and conventional steel springs on the other Cayenne models.