Don’t be fooled by fuel fallacies
Are oil-additive and fuel-optimising companies taking us for a ride? ANZET DU PLESSIS visited mechanics and engineers to find out.
For those who watch the news, one particular sentence – uttered all too often in South Africa – strikes panic into the heart of all viewers. The details differ, but the important phrase is always there, sounding something like “an increase in fuel prices next week Wednesday”. In addition, tolling in Gauteng and high living costs have businesses and families cutting as much as they can on the budget.
With the ever-increasing financial pinch in mind, you’ll be excused for wanting to believe in the many gimmicks and tricks around that promise to save you fuel. The efficacy of fuel efficiency gadgets, chips and additives are an old debate, but by no means an exhausted one.
If so many of these fuel-saving devices are merely gadgets, how come all their websites have raving reviews and testimonials? One theory is “pragmatic fallacy”, which has a lot to do with the placebo effect. Found quite often in the alternative medicine field, pragmatic fallacy is when something is deemed true because it works. Here, something “working” could be as simple as something making you feel better, or feeling satisfied.
Rob Handfield-Jones, who heads up driving.co.za and is a FOCUS contributor, agrees. “People subconsciously change their driving styles to accommodate the belief that they will save fuel. If such devices had any value at all, motor manufacturers would fit them in the factory and use the alleged savings in massive advertising campaigns touting the fuel-efficiency of their models versus those of their opposition.”
On the other hand, many of these products are potentially dangerous.
Many experts report that these additives are currently either ineffective, or dangerous. Another problem with all these products is the obvious argument that if automakers and fuel/oil production companies could somehow advance their products to get a competitive edge, they would. Also, if rolling-road or dynamometer-test results are not quoted on products, there is already reason to be very sceptical.
Additionally, mechanics we spoke to warn against these products. They claim that, despite what it says in the label, they can tell from particle build up in engines when individuals have been using additives. They went on to say that automakers often optimise engines as much as the vehicle can handle – inferring that various parts of vehicles cannot handle the performance enhancements these devices claim to provide.
We asked experts – engineers and mechanics – about various devices and products.
The old magnet-around-the-fuel-line debate doesn’t deserve nearly as much attention as it gets. Manufacturers of these products claim that the magnets will “align the fuel molecules”, following the assumption that some fuel molecules may be travelling in clusters. The magnet supposedly draws them out of their knots and makes them march like soldiers in a row. The bottom line is that fuel particles are non-polar. In other words, they are not magnetic in any way. Besides this very simple scientific fact, if molecules were to be aligned by the magnet, they would simply go back to their supposed “clumps” when they’ve moved past the point in the fuel line where the magnet is attached.
Fuel catalysts are devices fitted inside the fuel line or dropped into the fuel tank. They’re mostly tin-based products, and are meant to act as a catalyst for the burning of fuel. While tin is present in some fuel catalysts, it’s not a major catalyst for hydrocarbons. In oil refineries, catalysts mostly consist of aluminium and silicon. Catalytic converters containing platinum, rhodium and palladium are used in vehicle exhausts – not tin. Experts report that the use of an additive such as tin could not only be a waste on many, but could be detrimental to the efficacy of your internal combustion engine. Also, fuel burns at a specific tempo for a specific speed. In the case of both the spark and injections, timing is essential. The central part of the burn must occur at the optimum moment – a detail that has been worked out by vehicle manufacturers with a great amount of precision.
Even more importantly – and this argument is valid for all fuel additives – fuel burns at a percentage of between 98% and 99% on modern cars. If a product were able to cause fuel to burn faster, more efficiently or more completely, it would only do so by 1 – 2%. This is nowhere near the claims of 10 – 30% power and fuel economy improvements quoted by manufacturers of the products.
The addition of acetone to fuel is mostly suggested for petrol engines, where it is said to enhance vaporisation and thereby reduces the amount of fuel that leaves the engine un-burnt, and is quite a popular idea in racing circles. Acetone does seem to have an effect on fuel consumption, but it’s a tricky business. Reports suggest that too little acetone has absolutely no effect, and too much has a negative effect on fuel consumption. Since vehicle parts differ greatly from one to the other, what might have zero side effects in one car/truck could lead to the erosion of fuel pumps and the swelling of components in others.
The theory behind platinum injection is much the same as that of catalytic converters – platinum (amongst other elements) helps to convert un-burnt hydrocarbons into water and carbon dioxide. The argument is that, if introduced before combustion, platinum will cause fuel to burn faster. Again, the margin for improvement of combustion is very small. Also, any catalyst would essentially accelerate combustion – as is the claim. The problem with accelerating combustion in any way is that it would then no longer match the ignition timing on the engine – which manufacturers have gone to great lengths to optimise.
Additionally, ex-BMW and Bosch engine-optimisation engineer and well-known writer of “Tony’s fuel saving blog” suggests there is another, more fundamental problem. Most of these products use engine manifold vacuum as a way of drawing their platinum solution into the engine – saying that the larger the vacuum, the more platinum is getting through, the better the results. However, the air flow to the engine is not highest at high vacuum, but highest at full throttle when there is no vacuum at all – making the whole exercise seem counter-productive.
Air-bleeding devices are plentiful and varied, but the argument against them is the same. Fuel needs air to burn, and there’s a specific, optimal air-to-fuel ratio (called the stoichiometric ratio) at which combustion engines burn fuel. Air-bleeding devices “bleed” air into the inlet manifold, so that fuel has more air to burn with (making it leaner). This means that the air meters or carburettors are bypassed. While this may have been effective on older cars, most modern cars have sensors in the exhaust systems that monitor the ratio. The readings from this sensor affect how much fuel the engine management system adds or removes to get the mixture back to optimum ratio.
Atomisers and vaporisers
Petrol isn’t introduced into the intake manifold as liquid, but as a mist, which vaporises and burns much faster. Again, these devices would probably have significant effects on older engines, but as the modern injector is incredibly small, vaporisation is already as good as multimillion dollar research allows it to be.
Oil additives are probably the most common devices we are exposed to in advertising. Different oil additives are necessary when driving very old cars, or when cars aren’t driven very often. Those that claim to enhance performance or consumption, however, do so on the basis of improving vaporisation – which is optimised already. If your vehicle runs on poor quality fuel, oil additives can help clean the engine.
Those oils that claim to reduce friction may actually have a considerable effect in reducing fuel consumption. Experts suggest using high-quality synthetic or semi-synthetic oil from reputable manufacturers. Many automakers go so far as to suggest the oil that is specifically useful to their engines – and as it is in the automaker’s best interest that your vehicle run smoothly, this is solid advice.
How do you know it’s a gimmick?
• Any improvement over 5% can be treated as exaggerated, as automakers spend millions to achieve less than that.
• Legitimate products will quote test results from reputable, recognisable institutions, and will have dynamometer results or drive cycle tests tabulated.
• The product relies on testimonials rather than proof in order to sell.