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80SCOOL Trips

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Information Day

It started at 1pm sharp where everyone assembled in the workshop of the impressive new APS / Safari facility where GC introduced staff members David and Rob.

David gave everyone a complete run through of the history of the diesel 4x4, including basic diesel combustion principles, inline and rotary injection pumps, and the events and reasons leading up to the introduction of electronically controlled diesel fuel injection systems.

After a short coffee break he ran through the company history of Safari 4x4, some projects they had undertaken and their discovery of the Unichip overseas. He then explained the process of APS's subsequent involvement in the further development of the Unichip, and it's adoption to the diesel application and why. David outlined why the Dtronic with its adjustable timing control stood out from other units available on the market. The 24 guests then had opportunity to ask further questions regarding fitment, warranty concerns, etc., before we headed into the dyno cell.

Once everyone was in the sound proof room, with its purposely designed air circulation system, Rob gave us a run down of all the gear he had at his disposal, all linked to the DynoDynamics 4 wheel dynomometer.

We watched as a HDJ79 turbo diesel ute was ran up and down on the dyno until warmed up, then a power run was recorded. GC gave a quick talk of the contents of the Dtronic kit, as the glove box was then opened up and the Dtronic installed.

Rob then ran the ute and recorded another power run with the results quite obvious for all to see on the monitor. He then gave us a quick demonstration of the Dtronic's abilities, and showed us what difference being able to adjust firstly fuel, then timing, while holding the vehicle at a fixed load could do to it's power and torque outputs.

Although the day was passing quickly, a volunteer with a 3 litre N----n allowed us to see the before and after results of what the Dtronic did for them. Of course the big Cruiser was much more interesting to watch, and listen to ;-)

We reassembled back in the workshop for a final question session with David, and the day was over. Many of us adjourned just down the road to the Dorset Gardens Hotel for a meal and drink or 2.

A big thank-you goes to APS staff David and Rob for volunteering their time, and to GC for organising the day for the Lcool Community. I certainly enjoyed it, and I'm positive everyone who attended did also.


Greg Goulden.

Diesel Mapping

As discussed in the Diesel Tuning Article, independent mapping of fuel, injection timing at many combinations of throttle position and engine RPM is highly desirable in order to achieve high power and torque yet with good fuel economy and engine durability.

As we discovered on the day, the DTRONIC is unique in the Australian market in that this is the only unit that not only optimises fuel and injection timing independently, but also maps these parameters at each combination of throttle position and engine RPM.

In the picture above, the left hand monitor shows one of the timing maps. Effectively it is a grid of adjustment values with throttle position along the horizontal and engine RPM along the vertical. This give hundreds of points of adjustment at each combination of throttle and RPM. The fuel map looks very similar to the timing map screen, though of course the adjustments in the fuel map apply to the amount of fuel injected at that combination of throttle position and engine RPM.

The benefits of comprehensive mapping rather than bulk adjustment through simple overfueling devices became clearly evident when the factory turbo 79 Series was fitted with the DTRONIC and run on the dyno - See Dyno Graph Dissection at the end of this information day report.

Rob, Safari's chief tuner demonstrated the methodology used in arriving at a safe and effective map for each vehicle model/engine combination and introduced the LCOOL group to the tuning unit used to adjust fuel and timing - and then storing it to the DTRONIC.

The had controller shown below, plugs into the DTRONIC computer and contains two dials and a button. One dial adjusts fuel and the other injection timing. The button saves that value to the DTRONIC.

Rob's demonstration involved holding the car steady under load on the dyno at one mapping point (50% throttle & 2,000 RPM). He then proceeded to turn the fuel dial up and down and the power output varied markedly. He then adjusted the timing dial and again the power output varied accordingly. When performing actual tuning work though, Rob explained that the vehicle is fully probed with gas analyser equipment, combustion temperature monitoring, environmental & coolant temperature, acoustic equipment etc. etc.

The sound proof dyno cell we were in also had the ability to adjust the climate so that Rob can test and tune in high ambient temperatures. Mind you, there were more than one of us that wished the temperature was turned up a few degrees given that we were in Melbourne on a cold wintery day.

Turning the temperature up is a very important aspect of diesel tuning because in ambient temperatures above 30 deg C, the temperature in the top tank of the radiator rises proportionately to the ambient. By improving and optimising the injection timing maps over standard, combustion temperatures are reduced markedly. In some cases by up to 200 deg C! This is vital for engine durability under extreme conditions.

With the ability to control and monitor the operating environment along with the voluminous information being logged by all the data acquisition equipment ensures that the EFI parameters and safety features such as temperature compensation contained within the DTRONIC are spot on before any road testing even begins.

All up it was a very impressive and informative demonstration. The important issues raised and answered contained many aspects that very few of the attendees had ever thought of, let alone realized the benefits of.

Dyno Graph Dissection

The dyno graph above was created on the day using a factory turbo diesel 79 Series running on BFG AT tyres. The graphs show the power and torque measured at the wheels of the vehicle in standard condition and power and torque after the installation of the DTRONIC computer. All of this data of course is graphed against engine RPM along the bottom axis.

The lower two curves are wheel torque (Tractive N) and the upper two curves wheel power (kW).

To give us all an idea of just how accurate the Safari dyno is, Rob demonstrated the power lost at the wheels by switching the headlights on and off. Sure enough, with the lights on, the additional load caused by the alternator delivering more current to the electrical system could be seen quite clearly on the dyno computer screen!

Let's concentrate on the two torque curves first. The gap between the standard curve and the DTRONIC curve show the improvement in torque at that RPM point. Clearly evident is the substantial improvement in torque at the lower engine RPM range. The gap however closes up towards the higher RPM range.

As Rob explained, additional fuel with appropriately adjusted injection timing can be added in the lower RPM range where it is safe to do so. However, at high engine RPM, the test data and field testing show that it is not wise to apply that same strategy as seen at low RPM. In other words, the adjustments at low RPM are entirely different to those at high RPM. The engine is optimised to ensure that the maximum safe torque is produced at each and every RPM point.

At that point Rob looked skywards with a look of thanks. If he were locked into a simple device with one bulk fuel adjustment only across the entire RPM range, he would have had to have used the critical value used at high RPM and applied it everywhere. That means that low RPM torque would have suffered considerably.

Above all it was the improvement in the spread of torque that was so impressive. At any point between 1,400 RPM to 3,200 RPM, the DTROINC delivered more torque than the standard engine could muster at its peak torque point at 2,050 RPM.

Similarly, the power graphs show that when equipped with the DTRONIC, this engine produced more power between 2,500 RPM to 3,700 than the standard engine's peak at 3,100 RPM.

Again a very impressive and powerful demonstration of not only the benefits of the DTRONIC, but also just how important it is to be able to optimise the EFI parameters at each point in the RPM range.

Interestingly, Ron, the owner of the test vehicle wasn't about to let the DTRONIC be removed from his vehicle and purchased the computer there and then.