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Lexus 600hL One

Re Lexus 600hL. I spent some time earlier this year with one of those cars. The owner,a property owner in South Australia,wanted a 4 wheel drive after he kept getting bogged with his Statesmen Grange while driving around the paddocks. He didn't want a land cruiser or similar because he's elderly and he couldn't get into them. So he bought the Lexus,at that time I think there were only 3 in OZ. He uses it to drive all over his farm (!) and despite the cost,it doesn't get treated any differently to any other farm hack. All in All it's an impressive car though. Cheers!

Ron Bunting


Lexus 600hL Two

Re Lexus 600hL.

I take you to task regarding the following statement "...Those figures are in the order of 20 per cent better than would be achieved by a petrol engine car of similar size and performance; a diesel might do as well but no current diesel in this class has similar performance."

What class exactly do you see this car - I think Audi A8 somehow might be a competitor?

Again another quote (no not from Audi website) "Power for the new Audi A8 diesel comes from a big 4.2-litre V8 turbocharged unit with a hefty 650 Newton metres between 1600 rpm and 3500 rpm, and 240 kilowatts at 3750 rpm. These torque numbers mean almost all drivers will be operating the engine in its most efficient range virtually all of the time.

The engine has a tremendous surge of energy and can power from a standstill to 100 km/h in only 5.5 seconds. It took a sports car to accelerate like that not many years ago – a sports car with a thirsty petrol engine. Yet the Audi diesel’s official fuel figure is only 9.7 litres per hundred kilometres."

And the price? $220,000 so probably addresses the shortcomings of performance and is base price is cheaper than 660hl. Oh and thats the 4.2 v8 version, should you wish to save a few dollars then 3.0TDi is around $171,000 and eases itself to 100 in 7.9secs.

Now I wonder what the other Germans offer as well for the money....

Simon Brown


Yelling Praise



United States

Wrong Resistor

In your How to Electronically Modify Your Car, Part 3 there are some problems regarding the calculation for driving an LED. The actual calculation works out the required resistor for the maximum LED current of 75mA based on a 12V supply. The resistor required is determined as 131 ohms. A 120 ohm resistor is recommended but this would increase LED current to 81.66mA and this is greater than the maximum LED current. Also the use of 12V is not overly practical because a car supply can be up to 14.8V when the battery is fully charged. Using the 120 ohm resistor as an example for driving the LED would have a LED current of 105mA (assuming 2.2V across LED) and 1.32W dissipation in the recommended 1W resistor. Generally driving the LED at its maximum current would cause temporary blindness. Beter to run the indicator LED at a lower current at say 20mA and use a 620 ohm 1W resistor. As a guide a resistor is not allowed to dissipate more that 50% of its rating to allow for adequate heat dissipation in a high ambient temperature.


Thanks - an addition has been made to the article.

Too Old

regarding the Mixture Modifier story republished recently. bit old isn't it? i don't think the site's even sell the item any more but you could do the same thing with a t-piece and boost controller for $35. other than that the website is great, keep it up.


We thought the article showed a very simple technique that, as you say, could easily be done by other, cheap means.

Recumbent Trikes

I've been looking over your full suspension tadpole trike writeups and would like to learn more - I aim to build one myself. Would you be able to recommend some good design references? Also, I was looking at your last two designs and have been wondering why rather than having the front suspension arm pivot axes parallel to the central axis, you oriented them at an angle?  It seems that Nick Andrews took great pains to do this on his GNAT trike as well.

Ethan Davis
United States

Other than our articles, we don’t know of any references on building suspension trikes.

The pivot axes of the front arms are inclined to create semi-leading arms. This lowers the height of the roll centre, improves effective stiffness under brakes, and allows semi-leading steering arms to be used without introducing bump-steer (toe changes with suspension movement).

Note that this year we will be covering designing and building a new type of suspension, human-powered trike.

Wrong Comparison

Re The Technology Jump That Isn't Going to Happen.

I discovered your article because I'm trying to find a couple of these before they become land fill, sadly the one you had pictured is the model too early, and by the sound of it, is no longer in one piece.

I fear you have made a fatal comparison. The golfball typewriter itself was a huge jump forward in mechanical technology, and in actuality has fewer individual moving parts than an ordinary electric typewriter of that era. The problem with servicing the damn things is that everything is balanced under tnesion and you need five spare hands to hold bits while you move one bit into the right place.

Perhaps you should be comparing the golf ball typewriter to the Jervang, the Wankel, the Rotary, or the Split Cycle engines, all of which have fewer moving parts to achieve the same job...

But yes, we need that step over the precipice to the "daisy wheel" version of the car: three small electric motors; paper feed, carriage movement, disc spin, and a hammer.


Article Corrections

have had my bmw507 for over47yrs. and had goertz as a roomate for some yrs. your article on the car had many errors! for instants  my 507 is a 1960 and is probably the last.


United States

We are always happy to correct articles if:

1) the person suggesting the corrections has the demonstrated expertise in the field

2) the corrections are supported by further evidence, eg references, documentation, etc

3) the corrections are listed in a methodical way

Can’t Find It

I have 2 405srdt pugs and am interested to find out about the mods you made to yours but have not been able to find any details??


Do a site search under ‘Peugeot 405’.

Oxygen Sensor Signal Modification

I am installing a digital fuel adjuster on a 1993 isuzu trooper, I have installed hho on the trooper and need to fool the o2 sensor. I have read your articals on the dfa (starts at The Digital Fuel Adjuster, Part 1) am hoping you are able to help with changing the delta voltage into volts, I am working with a o2 that only has 1.0 volts, I am trying to understand how to tune the dfa from input volts to output delta volts. any help would be great. thanks

Raymond Wilson

United States

We don't believe that it is possible to effectively modify air/fuel ratios by intercepting a narrow band oxygen sensor. See Running Lean for Economy.

Bus Boost Control

Hello, could you please answer a question for me? I just read your tech notes (see DIY Boost Control) on how to make an in car boost control for a non ecu engine. Great stuff. I have a turbo intercooled diesel 3.8lt Hino minibus (grey import) with a rear engine. The vehicle is 7 meters long. I want to add a boost control that I can adjust from the drivers seat. Does it matter how long the tube is that runs to the needle valve? Would 7 meters be too long and have an adverse effect on the setup? Same goes for boost gauge. This I could over come by fitting a stepper motor gauge but would rather not spend high dollars. Any advice would be fantastic - as so far no-one can answer these question.  


The longer the plumbing to the needle valve, the more boost over-shoot that will occur on transitions. The length of hose to the gauge will make little difference to gauge readings, except perhaps to slow the response rate a small amount.

Alternator Loads

Could you do a feature/article on calculating how big a alternator you would need ie if putting in a big sound system and big spot lamps. I think this would be in the style of your current articles. Yes I did a Autospeed search and couldn't find what I need.

Jerrylee Buchanan


Basically, just add up all the loads that might all be running at once. Eg 100 watt driving lights x 2 = 200 watts load. 10 amps current draw by the amplifier = 10 x 13.8 = 138 watts. Then do all the other loads. When the total is added up (in watts), divide by 13.8 to get peak current draw in amps. The alternator needs to be able to supply that output. How to Electronically Modify Your Car, Part 3 has more on watts and amps.

Euro Accord Detonation

I read your article (see Honda Accord Euro) on the new CU2 model Honda Accord Euro and I refer in particular to where you wrote:

"The minimum fuel octane is 95 RON; we inadvertently added some 91 RON fuel to one of the cars and the engine could be heard detonating, especially at low revs in tall gears when using small throttle openings. (The other car detonated on the fuel provided in the car by Honda - and then also on the 95 RON we added!)"

Many Honda fora (as well as Acura TSX) make mention of this detonation problem. The usual response from Honda dealers appears to be to at first deny the problem and then advise purchasers to use 98 RON petrol (which apparently doesn't solve the problem but is an added expense to Euro buyers).

Escalation to Honda Australia appears to result in return phone calls (nothing in writing) saying that Honda will warrant engines affected by detonation and that Honda Japan is working on a fix. In the meantime, and as the Honda Euro manual states, detonation will cause long term damage to engines (which might not be apparent until after the warranty expires).

Did you discuss or mention the detonation that you experienced with Honda Australia? Have you had any feedback from Honda Australia?

I don't own a CU2 Euro but I was considering it.

Ross Finocchiaro


We told the tech person at the Queensland Honda office of the detonation we’d heard in the two cars. We’ve heard nothing from Honda since.

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