The wildly fluctuating unleaded petrol price cycle may be a great frustration of many South Australian motorists, but they are faring better at the bowser than drivers of diesel vehicles.

Analysis of fuel prices shows that during 2018 the driver of an unleaded petrol car, who can be subject to profiteering of up to 20c per litre at the top of the price cycle, was almost $100 better off across the year, without even shopping around.

MotorMouth spokesman Chris Huth said despite there being numerous other factors to consider, petrol drivers would have saved around $94 in 2018 if they filled up weekly at the same time as a diesel driver.

“When you look at average prices, or point in time price comparison between unleaded and diesel, there is no doubt that there are savings to be made by purchasing unleaded,’’ he said. The analysis came as motorists were urged to fill up at petrol prices near two-year lows.

The comparison used by MotorMouth in its analysis was a small diesel car against the same car with a petrol engine, both with a 50-litre fuel tank capacity and both filling up every Saturday throughout 2018.

Importantly, the $94 saving is the advantage of the petrol-powered car before any shopping around is factored in.

That is where the Adelaide market heavily favours the petrol motorist, who can at times buy at 20c per litre cheaper at one outlet than even nearby stations because of swings in the price cycle and competitive independent retailers. Diesel prices do not follow a cycle.

“If you dig deeper into daily prices, and look closely at the price cycle, the savings would likely be even more significant for petrol motorists,’’ Mr Huth said.

“In a typical unleaded price cycle, diesel is only cheaper than unleaded for 3-5 days and only by 3-5c per litre.

“For the balance of the cycle diesel is more expensive than unleaded and at unleaded’s lowest point the difference can be as much as 25-30c per litre.

Mr Huth admits there are many factors beyond price that make the battle more complex.

“This does not take into account any of the additional factors related to running a diesel vehicle regarding efficiency, servicing costs or engine longevity, they are purely based on a ‘per litre’ cost comparison,’’ he said.

Diesel vehicles typically cost a premium to buy however their engines can be 20-30 per cent more fuel efficient than a similar petrol engine.

The RAA urged motorists to take advantage of petrol prices hovering around two-year lows. The average price for unleaded across Adelaide on Monday was 109.2c/l, with some outlets selling for 99.9c/l, while for diesel it was 128.7c/l.

Some retailers were beginning to spike their prices late in the day, with motorists implored to shop around.

Extracted from Adelaide Now