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Some of this week's Letters to AutoSpeed

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Mixed Ps and Fs

A small thing, but to avoid confusion you may want fix your references to "DPA" in the Installation section of the article The Digital Fuel Adjuster, Part 2. As there is a DPA (Digital Pulse Adjuster) this may get confusing....

P.S. You guys are awesome! I bought the Silicon Chip mag on these babies from Jaycar and can't wait to get stuck into these things. Brilliant little projects with HUGE potential. Keep 'em comin’!!!

Cameron Shipway

Well spotted – now fixed. Get stuck into those kits!

Lexus V8 DFA’d?

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I read your article on the DFA and how successful it was on your Lexus LS400.

As a super moderator on the website I'm intrigued how you got the Lexus to run with the DFA as the Lexus AFM produces a frequency signal (like all Karman Effect systems) not a voltage.

Any comment would be appreciated so I can pass them onto our 1700+ members. Most are looking for a viable alternative to aftermarket ECUs.

Rod Garnett

As shown on Page DI-30 of the factory workshop manual, and easily able to be measured, the July 1997-onwards UCF20 series Lexus LS400 uses a voltage-outputting hotwire airflow meter. If there is enough interest, Silicon Chip will do a frequency output version as the next Digital Hand Controller project. Write to the magazine at

DFA for Supercharger?

I have been reading with interest your articles on the Digital Fuel Adjuster (DFA) and was wondering if it is possible to use this to add a supercharger to a previously NA engine? Could you use one that switched in under boost, or would just positioning the AFM before the supercharger see the extra load and allow you to compensate accordingly? I assume this would be harder to do with a turbo setup?

Ross Goddard

Yes, we suggest positioning the AFM prior to the supercharger and using the DFA to tailor the fuel curve. This will work regardless of whether a turbo or supercharger is used. In fact, we currently have a supercharger fitted to one of our cars and are using the DFA to set the appropriate mixtures.

DFA for Blown V6?

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Can I use the DFA on a car fitted with a MAP sensor? I have a VT Holden Commodore with the supercharged engine and am keen to lean off the ridiculously rich mixture.

Scott Goodman

Yes, the DFA can be used on vehicles with a voltage output MAP sensor. Go for it – and please let us know how it turns out.

DFA MAF to MAP Swap?

Is there a way to convert my MAF into a MAP set-up using the DFA? Do you have or can you recommend a MAP unit that I can use in conjunction with the DFA? Is there any calibration needed to run MAP?

Jeoff Chen

You won’t be able to convert from a MAF to MAP sensor system using only a one-dimensional interceptor. The vehicle’s existing ECU is configured to read only a mass airflow load input – not a manifold pressure signal. A better approach to eliminating intake restriction is to use an airflow meter bypass (as detailed at Airflow Meter Bypass, Part 1. The DFA can successfully be used to maintain driveability and correct mixtures, even when a large diameter bypass is used.

DFA + Ignition Control?

Again, I'd like to thank you all for continuing to provide the best automotive magazine available!

I've been eagerly awaiting the arrival of the performance electronic kits for months, and so was absolutely stoked when I saw the kits available at my local Jaycar toward the end of 2004.

I've now built the IEBC, DFA and a couple of the gauge products. I'm absolutely stoked with the performance of the kits. I'm slowly integrating them into my BG Mazda Familia GT-X.

I am, however, interested to know if you are intending to develop an ignition interceptor? The obvious shortcoming of the DFA for more serious modification is the ignition timing issue.

I have seen that Silicon Chip has, in the past, developed programmable ignition systems.  However, there appears to be no provision for a load based retard function as would be useful in a turbocharged car. Are there plans for such a kit? Alternatively, would it be possible to integrate the original programmable ignition kit with one of the new high performance kits to provide ignition modification?

Adam Seedsman

Glad you’re happy with the DFA in your Familia. The existing programmable ignition kit isn’t the perfect solution for your application. Depending on the success of existing performance kits, Silicon Chip will be looking at future kit development - and an ignition timing interceptor is high on the list.

HSV Changes

I have 2 questions to ask AutoSpeed or some of the readers...

1. I am looking for a towbar that will fit my 2000 HSV R8. I would like to avoid cutting the skirt, or at least make it look okay when the hitch is removed. Any suggestions for a minimum tow weight of 1500kg?

2. I also need to replace the tyres on the same vehicle and I would like to know if you have done any recent tyre comparisons?

Daniel Jackson

Readers - any advice on tow hitches and tyres to suit this particular vehicle?

Missing a Drive-belt Tensioner...

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Thank God someone has been brutally honest about Holden’s new Alloytec V6 (Holden Acclaim Wagon). Your words have echoed my thoughts. My current car is a ‘98 TF Mitsubishi Magna Advance 3.0 litre 5 speed. The one thing that I enjoy about this car is its engine, which is so full of character it just begs to be driven with enthusiasm. Not so the Alloytec. What a bland and characterless engine. It sounds like it has done a drive-belt tensioner - all that whirring and thrashing with not much result. I hear that Alfa is to be picking up the 3.2 litre version - they must be able to work miracles!

David Lewis

Crown Info

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I have an imported 1987 Toyota Crown Royal Saloon with a 1G-GZE 2.0 litre supercharged engine and I am having trouble with the timing - could you possibly help me with any information? If not, do you know where I could find out? I have so far been unable to get any manuals.


Finding a workshop manual will be very difficult – and it’s likely anything that you do find will be in Japanese... Do any readers have some useful links?

Electric Power Steering Fitment

I have been combing manufacturers worldwide such as Delphi, Toyoda, NSK, etc for options relating to retrofitting a column mounted electric power steering into my competition car (it is a competition-only car, so having to modify the car to fit whatever is available is not a concern). However, I have come up blank from all of them - it seems to be almost offensive for them to lower themselves to speak to someone who is not a vehicle manufacturer. Can you help me find or at least give me some advice on where I might be able to source such a system and control unit for it?

Drewe Cantwell

At a wrecker... Plenty of smaller cars these days come with electric power steering, and some small Japanese cars (eg Daihatsu Mira) have been using it in Japan for at least a decade.

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