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Claims on Prozone Fuelsaver's website for its Fuelsaver Magnetic Fuel Saver, on 8 March, stated "Find Out How The Prozone Magnetic Fuel Saver Works. FUEL CATALYST + MAGNETIC FIELD = OCTANE BOOSTER. Prozone Fuelsaver fuel saving device combines two proven scientific fuel enhancement processes - a tin-alloy catalyst and a magnetic field - to condition the fuel, gasoline (petrol) or diesel before it reaches the combustion area of the engine. This is in contrast to standard catalytic converters which act on the exhaust gases after they leave the engine and, thus, can have NO EFFECT on the actual combustion process.

On entering the Prozone Fuelsaver magnetic fuel saver, the fuel passes over one (FS1) or more (FS2-FS4) complex alloy cores. The cores are specially designed to create turbulence in the fuel flow path, enriching the fuel and maximising the take-up of trace metals. The fuel then passes through a sintered ceramic magnetic core which alters the free electron structure of the fuel, polarizing the fuel hydrocarbons prior to combustion.

The two processes, chemical and ferro-magnetic, essentially alter the molecular structure of the fuel to encourage better bonding between fuel molecules and atmospheric oxygen promoting a more complete oxidation of the fuel and, hence, a more efficient combustion process. Additionally, the metal alloy catalyst is deposited in molecular quantities in the combustion chambers, coating the vulnerable surfaces of the valves, valve seats and piston rings to prevent overheating, aid sealing and enhance engine lubrication.

The results of improved fuel combustion are a significant reduction in harmful, exhaust, emissions, a noticeable increase in engine power output, and a measurable improvement in fuel economy".


The complainant challenged whether the efficacy claims for the product were misleading and could be substantiated.


Prozone Overseas Fuelsaver Ltd (Prozone) provided a copy of a performance test report of their Fuelsaver device which was carried out by the Road Transport Department of Soundwell College in Bristol. They believed that that report substantiated their claims about their device.



The ASA noted that the device had been tested on two cars - 1989 Vauxhall Cavalier 1.6L and a 1987 Citroen BX19RD - which were considered to be modern cars at the time the tests were carried out in 1992. Soundwell College tested the Fuel Saver on the petrol engine of the Cavalier and they tested the device on the diesel engine of the Citroen.

We noted that both cars were standard specification with no modifications to either the engine or equipment. Both cars were tested first without the device fitted and then with the device fitted. We noted that the cars were tested in laboratory conditions using a dynamometer and with the engine under full load conditions and at different road speeds (40, 60, 80, 100 and 120km/h). We noted further that engine cooling was supplemented by a large mains powered fan that delivered air to the front of the vehicle which enabled the engine to maintain a stable temperature during the test.

Both cars were tested for vehicle performance which included power output at the engine, exhaust emissions and fuel economy at speeds of 40km/h, 60 km/h, 80 km/h, 100 km/h and 120 km/h. The report showed that overall, for the Cavalier, the device showed an average improvement of 4.34% for power, a 7.36% and 3.86% average improvement in carbon monoxide and carbon dioxide emissions and an overall average improvement of 22.2% for specific fuel consumption.

The report concluded that when the device was fitted to the Cavalier, at every speed there was a reduction in the output of carbon monoxide. It stated that efficient engines converted most of the fuel/air mixture to carbon dioxide. It concluded that with the device fitted, the results showed that carbon monoxide had been substantially reduced which matched the corresponding increase in carbon dioxide. The report considered that the more efficient combustion produced by the Fuel Saver was the most likely cause of the improvement in power.

The report showed the results of the fuel economy testing which looked at the fuel consumed by the engine, specific fuel consumption (SFC) and vehicle fuel consumption. The report explained that SFC measured the fuel consumers used per kilowatt hour and by measuring this type of fuel consumption, it allowed comparisons to be made with engines of different types, configurations and size on the same basis. The report concluded that whatever type of fuel consumption was selected, the results showed that the device, when fitted, had shown an improvement especially at low speeds.

The report noted that the figures were obtained from tests that had been conducted under full load conditions and it stated that there would be considerable difference at light load conditions. The report considered that because the “before” and “after” results had been carried out under the same conditions, it was the relative difference between the two which was important. It concluded that the SFC improved by an average of 21.8%, with significant improvements at low speed.

The report showed that when testing the 1987 Citroen, the results showed that for power developed by the engine, there was a 5.5%, 2.9%, 4.0%, 4.7% and 6.1% change when the device was fitted to the car, when driving at 40, 60, 80, 100 and 120 km/h respectively. The report explained that an indication of the “on the road” fuel consumption (vehicle fuel consumption - VFC) was achieved by noting the distance travelled and the fuel used. The fuel tank was refilled to the filler neck with the fuel gauge showing as “empty”. That process was repeated for each refill and the fuel consumption was calculated as litres of fuel used per 100km. The report showed that without the device, the VFC was 6.23L/100km and with the device fitted, the VFC was 5.91L/100km. The report stated that test showed a 5.14% reduction in fuel used per 100km travelled.

The report stated that the tests had been carried out on cars under full load conditions in a laboratory. It also stated that the results obtained by vehicles on the road would depend on road conditions, driving techniques, and the condition of the vehicle. The report noted that the tests had been carried out on modern cars with high grade fuel and it considered that it could be possible that even better results could be achieved with an older design power unit or lower grade fuel. We noted that the evidence provided had only shown that two modern cars (as they were in 1992) had been tested.

We considered that when testing a device like the Fuel Saver, that testing should simulate normal driving conditions by comprising of cycles that accounted for realistic loads, typical accelerations and other driving variables. We noted that whilst road testing was more realistic than laboratory testing, the inherent variability of road testing meant that it would often not provide the level of reproducibility required to ensure statistically significant results.

We noted that the tests were carried out in a laboratory using a chassis dynamometer and that the tests were undertaken at different speeds ranging from 40 km/h to 120 km/h at 20 km/h intervals and we considered that range of speeds accounted for different types of driving conditions e.g. town and motorway driving. However, we noted that the testing undertaken by Soundwell College showed the car under full load conditions, which we did not consider to be generally typical of normal driving practices.

We understood that the cars had been tested first with and then without the device fitted. However, we considered that the tests should have been repeated. We considered it was necessary to repeat those tests in order to provide an adequate level of accuracy and repeatability to allow the effect of small changes in variables such as emissions and fuel consumption to be correctly identified.

Whilst we noted that the testing had looked at the cars’ performance at a range of speeds, both without and with the device fitted, we were concerned that those tests had not been repeated and that they had been carried out under full load conditions. We were also concerned because the website suggested that the device would be suitable for all cars on the UK market, but we noted that the tests had only been carried out on two cars (one petrol engine, the other a diesel engine) that were considered to be representative of the market in 1992, when the test had been carried out. We noted that the claims were current and we therefore considered that further tests should have been carried out more recently on a wider range of cars. Because of those concerns, we did not consider that the evidence provided by Prozone was sufficiently robust to substantiate the general claims appearing on the website that the device could help to reduce harmful exhaust emissions, to increase engine power output and improve fuel economy.

Notwithstanding our concerns about how the tests were carried out, we noted that we had not seen any evidence that showed that the device worked in the specific way as described on the website. The report explained the methodology of testing but it did not explain how the device worked or how it was capable of reducing emissions and improving fuel efficiency. Because of that, we did not consider that Prozone had substantiated that the device, in the way described, could prevent overheating, aid sealing, enhance engine lubrication, offer improved fuel combustion, offer a significant reduction in harmful exhaust emissions, provide a noticeable increase in engine power output and a measurable improvement in fuel economy. We therefore concluded that the website was misleading.

The claims breached CAP Code (Edition 12) rules  3.1 3.1 Marketing communications must not materially mislead or be likely to do so.  (Misleading advertising),  3.7 3.7 Before distributing or submitting a marketing communication for publication, marketers must hold documentary evidence to prove claims that consumers are likely to regard as objective and that are capable of objective substantiation. The ASA may regard claims as misleading in the absence of adequate substantiation.  (Substantiation) and  3.11 3.11 Marketing communications must not mislead consumers by exaggerating the capability or performance of a product.  (Exaggeration).


We told Prozone not to make efficacy claims about the Fuel Saver unless they held robust substantiation for them.

CAP Code (Edition 12)

3.1     3.11     3.7    

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