IRONMAN 4X4’S BLACK OPS BUSH TRUCK

The first phase of our Ironman 4x4 Bush Truck build is the installation of a performance upgrade. I was expecting more people to ask why and I was a bit disappointed that most people just accepted it without explanation. I was ready to explain that the performance upgrade would help to compensate for the additional weight of all of the accessories as well as the larger wheel and tyres that we would be fitting to turn the Ranger into a serious bush truck. It would seem however that a performance upgrade for a diesel-powered double-cab bakkie is par for the course.

One only has to look at the back of any motoring magazine or do an online search to see a plethora of diesel tuning and chip companies advertising their products. Some of the performance gain figures that are quoted certainly make one perk up and take note. It is however easy to get confused as there are always two sides to the story: one positive and the other negative. Fortunately, some years ago, I was briefly involved with a diesel conditioning product from Canada and at the time I gained some insight into diesel engine performance.

Diesel engine performance differs somewhat from petrol engine performance and the means employed by tuners and performance gurus differ too. One of the main areas that effects engine performance is fuelling – the amount of fuel injected as well as the air-fuel mixture. In a petrol engine, too little fuel (a lean mixture) will cause excessive combustion temperature and the engine runs hotter. Too hot and you’ll start melting things. In some high performance engines, additional fuel is used to lower the combustion temperature. Too much fuel (a rich mixture) in a normal engine will cause the build-up of carbon and excessive unburnt fuel. This carbon build-up could foul the spark plugs and the excessive fuel will wash away lubrication on the cylinder walls leading to premature engine wear as well as excessive fuel consumption.

Diesel engines are a little different. At idle, a diesel engine theoretically runs lean. Without a throttle, the engine revs are controlled by the amount of diesel injected into the