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At the pump: Is premium fuel better for your car?

When it comes to trips to the fuel bowser, many of us are far more concerned about the numbers on the pricing board than the tech in the petrol we’re blasting into our beloved car.

It’s not illogical to think that the formula flowing through the pump is a simple chemical produced with relatively little effort, because… well… it’s just plain-old, ordinary petrol, right?

Not exactly. I don’t need to tell you that the auto fuel market is huge; that much is obvious. But when the product each fuel provider is offering is so homogenous, how do they secure a competitive edge over their rivals?

They innovate. Whilst it may seem like there’s little room for innovation when it comes to petrol, there are several key areas in which the oil companies are looking to add value for the consumer through refining their fuel further, using learnings gleaned through ongoing R&D.

These key areas include greater fuel efficiency, reduced component wear, and improved reliability. To this end, the oil companies have been steadily improving their offerings over the course of the last couple decades, introducing additives designed to extend engine life and maintain performance.

The tech behind these additives has become highly sophisticated; BP, for example, have just introduced two improved premium fuel offerings (BP Ultimate) designed to eliminate the majority of the unwanted deposits that build up in your engine over time within only two fills of your tank.

BP Fuel

But does it actually work?

Well, that depends on your car. The first thing you should do is check the manufacturer recommendations for your specific vehicle. These can be found in your vehicle handbook, though if that’s not on-hand then this information is usually readily available online as well.

BMW Handbook

There will be a recommendation for fuel grade and octane. Most modern vehicles (post ~2005) were tested, and are designed to run, on premium fuel and the manufacturer recommendations will reflect this. If your car is relatively new, you do stand to benefit from smoother running and improved engine life if you stick to premium fuel. Higher octane fuels are more suitable for higher compression engines (if in doubt, consult the manufacturer specs for your car).

If you’re rolling about in a significantly older car then you’re likely better off sticking with regular, non-premium fuel as you won’t see enough of a benefit from running premium. For example, I drive an MY89 car that was tested and designed to run on regular, 91 octane unleaded. I gain no additional benefit from running premium fuel or a higher octane, and whatever deposits have built up over the past couple decades won’t be remedied by fuel additives.

80s civic

Your 80s Civic is perfectly happy to be fed regular unleaded.

Premium fuel benefits

If you do own a relatively modern car, then the key benefit you’ll see from paying a few dollars extra for premium fuel is improved engine health.

Your car’s fuel system and engine is full of cavities and delivery lines that are prone to build-up of carbon and other deposits. As these deposits build up over time and use, your engine has to work harder to maintain performance and its many components become increasingly susceptible to premature wear.

cabon buildup

Carbon build-up extracted from a modern Audi engine after only 60,000kms.

For an analogous example that may be a bit more familiar, imagine the arteries in your body and the valves in your heart; if those clog up you’re in serious trouble. The same goes for your car’s engine.

It’s for this exact reason that companies like BP are investing so much time, effort and money into producing fuel that is specially tailored to eliminate these deposits and introduce protective additives that prevent further build-up.

The image below is of an intake valve with a pretty typical amount of carbon build-up for a modern car with conventional electronic fuel injection:

carbon buildup

It looks bad because, well, it is. Don’t stress; your car isn’t going to bite the dust overnight because of it, but if you’re able to reduce and prevent this build-up through choosing the right fuel then why not? Given that reliability is one of the key factors people consider when choosing their car, there’s really no reason not to improve it yourself by sticking to premium fuel.

clean vs dirty

Performance is another area that can benefit from your choice of fuel. Your car’s fuel injection system will function better if the key component, your fuel injectors, are clean (shocker, I know). What’s the difference between a dirty injector and a clean one? This:

injector deposits

Unimpeded fuel delivery through the injectors means your car will run smoother, for longer, and at full power.

So the next time you’re filling up, debating whether there’s any point in shelling out the extra few dollars to run premium fuel, consider what’s best for your vehicle, not your wallet. Engine repairs are far more expensive than the cost of picking up the premium pump.

Leave a comment

Comment (3)

    Adam

    Monday 28 March 2016

    Assuming sponsored by fuel company. This article implies new cars should run 98, yet my 2015 Kia, 2014 wrangler unlimited and my 2006 C200 compressor all run better and get more kms from 91.

    I see your caveat about checking manufacturers recommendations but the artcles overall message is to run 98, when most cars, unless a sports car, don’t require it. In fact, they’re not tuned for it and will run worse on 98. That’s the majority. Not cars that require 98 octane

    Reply
      Shaun Glover

      Shaun Glover

      Tuesday 29 March 2016

      Hey Adam,

      Appreciate the feedback thanks mate.

      I think there’s a bit of a misunderstanding here – the message of the article surrounded running premium fuel in modern cars, not a particular octane.

      As mentioned in the article, octane suitability is dictated by engine compression, for which you should consult your owner’s manual. Premium fuel is available in a range of octanes, just as standard fuel is available in a range of octanes.

      Premium is available in a range of octanes, so is suitable (and often recommended) for most modern engines due to the protective qualities of the included additives.

      Reply

    Gaby

    Saturday 24 September 2016

    Good article, but it does not mention that if you have got dirty petrol in the tank and that gunk works its way to the injectors, you are going to have a rough ride indeed (to say nothing of the poor engine!), until such time as the injector overcomes the fouling (unlikely) or by putting in a bottle of fuel system / injector cleaner and running for a few hours, carefully, until misfiring stops. At half-full, refill with PULP98 and continue to refill for one more tank. I speak from the experience of having picked up dud fuel somewhere along the line (91, general store-style stops in the country) and the above experience, and the ensuing remedy, has worked exceptionally well in my ex-CFA 2006 VZ Commodore wagon. PULP95 to 98 is all I put in the tank now, and all of my driving is at speeds of 100km/h+ on freeways — never any suburban errands or stop-start driving where you will not obtain any benefit from PULP. Because of this, I am achieving fuel economy of 7.3L/100km over a 440km freeway trip. I’m happy paying up to 30c more for PULP, getting around 660km from a near-full tank with travelling load.

    Reply