by Mike Mccarthy

Created on: March 23, 2009

Comparing diesel and gas, or petrol SUV's or 4x4's needs to be done on a like for like basis. There is little point making a comparison between a large engined petrol or gas 4x4 and a small urban diesel SUV.

Using the Mitsubishi Pajero, also known as the Shogun and the Monterro, dependant upon what part of the world the reader resides in, we will look at a particular model, that is available with diesel or petrol as an engine option.

We will take the 1996 Mitsubishi Pajero short wheelbase variant as our comparison model. Using the 2800cc diesel and the 3000cc petrol engines as choices here as apart from fuel usage, the vehicles are identical in every aspect.

The 2800cc diesel Mitsubishi Pajero has a turbo charger fitted to the engine, to aid responsiveness and to give a power output similar to it's petrol brother. This engine will provide the owner with an average mpg of approximately 25 miles to the gallon. This is of course dependant upon style of driving and not using the four wheel drive option.

The 3000cc gas, or petrol Mitsubishi Pajero has a normally aspirated engine with a V6 configuration. Again, an expected mpg is approximatly 25 miles to the gallon.

To some the fact that the mpg is pretty much the same between the two engine offerings may be surprising, particularly as many expect a diesel engine to provide better gas mileage than a petrol one. Both vehicles have an engine that is moving a car with a body weight of approximately two tons. Both vehicles transfer the power from the engine to the road via an automatic gearbox and transfer box. Both vehicles have a manufacturer expectation of a similar power output. So, it's not surprising that each vehicle requires a similar amount of fuel to make it go.

However, if the turbo charger was not fitted to the diesel variant, although performance would suffer, it would produce a better gas mileage figure than the petrol engine version.

In the UK, diesel fuel is more expensive than petrol. This means that in fact if one takes two identical vehicles, as above, the diesel is more expensive to run. Add to this fact that diesel fuel is messier to handle and has poorer cold weather performance, particularly when starting, then petrol is the better option.

There is one area where the diesel is better than the petrol engine version. Diesel engines provide more lower end torque, so it may be that if towing or off roading is your reason for owning a 4x4 or SUV, you may want to consider this.

When making comparisons, such as this one for diesel or gas engines, one must always make sure the comparison is a fair one, otherwise your results may not be accurate. If you are using this comparison as part of a purchase choice, dig into performance figures before making your choice.

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