2008 Skoda Octavia Comparo – Petrol vs. Diesel

Petrol vs. Diesel - Round Two

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- by Matt Brogan

Last month we featured the first of our three-part petrol versus diesel comparos with the contender, a funky Skoda Roomster, seeing the diesel variant come out on top by a country mile.

So this month, in defence of the title, we have the mid-sized Skoda Octavia Elegance in the ring to attempt an equaliser on our scoreboard of one-nil. With both engines offering decent performance, marvelous drivability, and comparable fuel economy, this is going to be a close one.

I first reviewed the Octavia earlier this year in the form of the surprisingly capable Ambiente 4x4 and was very pleased with the car as a whole. It offered dependable driving characteristics, volumes of versatile space, proven power plants and an overall feeling of quality which in my mind made the vehicle a worthy entrant for the next round of our challenge.

Pictured - Octavia Elegance TDI in 'Black Magic'

Now as cars go, the Octavia is a ripper, but we're not here to talk about the car as such, we're here to use it as a science experiment, a lab rat or guinea pig if you will, to determine the better engine when utilised for the purposes of a medium size family car.

So what's a family car used for these days? Well, everything it would seem. Chauffeuring the kids, getting to work, going on holidays, carrying the shopping, hauling gardening supplies, ferrying the out in-laws, you name it, the family car cops the lot. It's a thankless series of tasks and we quite often don't give our family car a second thought, until that is the bowser price starts climbing.

Now sure, this is only one part of a car's overall operating costs, and other factors like servicing and maintenance, insurance, and resale value must also be considered when buying yourself a new car. But as these are comparable on any car these days, our review will focus primarily on fuel costs and the drivability offered between engine types when tested in identical vehicles.

It's a timely exercise with bowser prices on the up-and-up so our aim here is to see just how these two vehicles pan out, which costs less and which will be better to live with.

As a family car could no doubt attest, the majority of its life is spent in the urban environment. Sure you may take the occasional weekend jaunt in the country or a holiday at Christmas, but as a whole, most driving is done in built-up areas. So, our test reflects this trend with about seventy percent of the driving for this review carried out in the urban environment.

Plenty of stop-start traffic, lower speeds and a lot of short trips made up the majority of our driving this week with the weekend devoted to putting some highway ks on the odometre. In all, we clocked up close to 1,000kms in each vehicle with some rather surprising results, especially on behalf of the petrol powered or TFSI (Turbocharged Fuel Stratified Injection) model.

But let's start in the order with which the cars were driven, and introduce the Octavia Elegance's fabulous 2.0 litre TDI (Turbocharged Direct Injection) diesel engine. With 103kW and an impressive 320Nm available it's an athletic performer, quiet and strong with enough pep to shame larger capacity petrol rivals. Torquey, linear acceleration comes freely after the inital lag which although minimal, is nonetheless noticeable and can be slightly obtrusive in peak hour traffic.

The DSG automatic does a fine job of keeping things on the boil once you're up and moving, and is always in the right place at the right time. No hunting, minimal thinking, and short direct shifts make for smooth flowing power that works seamlessly to the input from your right foot.

Over the longer country stretches the diesel is a brilliant performer, it overtakes effortlessly and eats up mile after mile without so much as a hint of losing steam, but that initial turbo lag may become distracting to many drivers meaning this car is truly at its best cruising on the highway where lag issues are of little relevance.

The combined fuel consumption average for the week returned a decent 6.6 litres / 100km all up, slightly over the ADR test results of 6.0l and it's worth noting that even under rigorous stop-start conditions, the TDI still managed to return a maximum of high 8s. Impressive.

Intriguingly though, our petrol contender had a few tricks up its sleeve and although typically speaking a petrol engine will out-drink a diesel almost two to one, the TFSI was not about to lie down for a kicking and put up a really good fight on behalf of its petrol brethren.

In this instance, the petrol model was turbo-charged which gave us a much more flexible drive from a smaller capacity engine. Lay off the throttle and you've got all the economy benefits of a smaller capacity four cylinder, but stick the boot in and that punchy turbo springs to life, with surprising and effortless performance.

This 1.8 litre example provides an ample 118kW with a hearty 250Nm of torque. These figures, whilst far from mind blowing, do a willing job of motivating the Octavia with negligible lag and much in the way of long legs and free spinning revs.

Day after day the TSI (petrol) model grew on me, which after the TDI (diesel) took some doing. The overall drivability afforded from such a small engine is staggeringly impressive and perhaps even more interestingly came at no real cost to the vehicle's overall economy.

The six-speed manual is a delight to use with short clean changes, close ratios and a brilliantly weighted clutch which even in very heavy traffic posed no real issues in terms of leaving you with a sore thigh. The drive is very responsive, especially from a standing start and in fact without the standard ESP and TCS turned on, Octavia petrol will break traction quite easily.

But performance aside, the most impressive part of the petrol model's drive has to be the fuel economy. The Octavia is a safe car, and therefore rather heavy but even with the added structure on board still managed to return a very respectable 8.4 litres / 100km combined average, reaching in to the mid 9s in heavy around town traffic.

Although this is a little over the ADR claims it is still a decent result given the level of usable power the engine provides for the rigors of big city traffic. Even with the boot packed full of camping gear and three people on board the petrol preformed very well and cruised comfortably at highway speeds.

So, who's the victor? Well with the exception of the noticeable turbo lag, the diesel is brilliant, and if it weren't for the vehicle's usage being more city orientated, the fuel economy figures alone would have won the TDI the crown. But as it stands I'm awarding this round to the petrol.

Although close in most respects I've gone with the petrol model for being cheaper to purchase, more user-friendly around town, and for offering a punchy and drivable package that's easier to live with on a daily basis.

Drive the pair and I'm sure you'll agree that although the diesel will gain you some fuel economy benefits, the ability to live with the petrol - and enjoy that turbo charged oomph - will see it come out a winner. One all!

Scoreboard - Diesel 1 : Petrol 1

Next month's comparo will feature the Hyundai i30.