It was the previous weekend when Harris Heinrich came up with a problem that his 2010 Cadillac SRX Turbo had suffered severe
internal damages while he was performing test drive. He also added the car had to be almost plucked from a mountain road side.
Harris was of the view that damages suffered by his car were partly due to misfuelling problems.
The V-6 of Cadillac needs 91 octane minimum. Lab tests revealed that SRX was driven on regular, implying that the car had been inadvertently filled with 88 octane gas instead of company mandated premium. At some point of his traveling, between 2000-2500 rpm – or normal speed during cruising along highway “ the management system embedded into the car engine finely adjusted air fuel mix-up and that caused a retarded spark. It also led to a turbo boost simultaneously, which further resulted into building up of catastrophic pressure in the cylinder chambers.
Now the question is if difference in octane level – only by a petty margin – can be responsible for breakdown of your vehicle. Low-octane could be one of the contributing factors for car’s breakdown but that was not the main reason. Use of regular fuel in any engine meant for premium usually doesn’t pick up any serious or immediate damage.
The fact that caused demise of 2.8-liter turbocharged V-6 in the Cadillac was detonation. It is caused due to premature ignition of fuel and in several locations in the combustion chamber. The several flame fronts lead to very high cylinder pressure that can cause death to engine parts. Unlike the lower-octane mixture, high-octane fuels take time to ignite and so occurrence of detonation is most unlikely during
time of their use.
Almost every modern engine features a knock sensor. On engines meant for use of premium fuel, the device adjusts if regular
is used. The sensor, which is mounted on the engine, identifies the rattle of detonation and immediately dispatches a signal to the engine computer that leads to changes in calibration to sort out the issue. In most of the cases, it simply means retardation of ignition timing. With late coming of spark, small amount of heat is generated and detonation won’t occur.