Note: This advice is given by the CAP Executive about non-broadcast advertising. It does not constitute legal advice. It does not bind CAP, CAP advisory panels or the Advertising Standards Authority.
CAP is aware of several products that purport to offer various benefits to vehicle owners. Those products can generally be divided into several broad classes, such as fuel additives, devices placed in contact with the fuel, air intake system, fuel intake system or exhaust system and electronic timing devices.
Claims associated with such devices typically refer to one or more of: fuel economy; power or torque gains; lead substitution; emissions reduction; reduction in engine wear; improved octane numbers and reduction in valve seat recession (VSR).
CAP is aware that some liquid additives have been proven to significantly reduce VSR. The ASA has accepted that a petrol treatment and valve lubricant and octane booster can significantly reduce VSR in engines using unleaded fuel. Marketers of similar products will need to hold proof that their products work in a similar way or are as efficacious.
Before advertising, marketers of devices and additives should ensure they hold rigorous evidence (in English) to support their claims Rule 3.7). They should consider whether their evidence conforms to these guidelines:
Any body of evidence would almost certainly include laboratory testing, undertaken by a reputable independent facility. Marketers should note that the ASA has upheld complaints challenging efficacy claims after noting the test results were considered to be insufficiently independent. Testimonials and sales figures are considered inadequate evidence to substantiate direct or implied efficacy claims about a device or an additive. We are not aware of an official register of test laboratories capable of carrying out emissions, fuel consumption or VSR testing work. A list of recommended independent organisations that have carried out relevant work can be obtained from the Society of Motor Manufacturers and Traders (SMMT) and the Department for Transport (DfT), Transport, Environment and Taxation, (TET 4).
Although road testing is more realistic than laboratory testing, the inherent variability of that process will often not provide the level of reproducibility required to ensure statistically significant results. Laboratory tests should simulate road driving by comprising cycles that account for realistic loads, typical accelerations and other relevant variables (full load conditions are not generally typical of normal driving practice). Such cycles, run under controlled conditions on a chassis dynamometer, should 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. Advertisers should be aware that the ASA has upheld complaints on the basis that marketers’ test results were not recorded under normal driving conditions. Testing equipment and methodology should comply with relevant national or international standards (for example, European Directives or US Federal Register requirements for exhaust emission and fuel consumption measurements).
Engines should be warmed up before a test is started unless the product is designed to minimise wear, fuel consumption or emissions resulting from starting a vehicle from cold. Furthermore, only vehicles that have been run-in should be used in tests. The duration of tests depends on the parameters measured, the engine power and the speed levels used. Marketers should be able to show that the duration of the test is relevant to the substantiation of a specific claim.
All tests should, as far as possible, incorporate a repeat reference element: the vehicle should first be tested without the product, then with the product and finally without the product again. Ideally, at least two tests of each element should be undertaken unless devices or additives are claimed to have a carry-over effect after they are removed, in which case at least three tests of each element should be undertaken. If relevant, carefully reconditioned cylinder heads and new valves should be used for each test. A formal statistical analysis should be undertaken to ensure the results are sufficiently precise. The ASA has upheld complaints against marketers when it considered that their results had not been demonstrated as reproducible, noting that the marketers should have incorporated more repeat elements into their test cycles (BVG-Airflow Group PLC, 21 April 2004).
Vehicles and fuels representative of the market addressed by the claim (usually the UK or European market) should be used in tests. The number of vehicles that need to be tested will depend on the nature of the claim that the tests are intended to support: the greater the range of vehicles that are said to benefit from the product, the greater the range of vehicles needed in the tests. No alterations should be made to vehicles. Complaints have been upheld against marketers who conducted tests on irrelevant vehicles (Ecoflow Ltd, 17 April 2002) and marketers who used fuel that was inconsistent with that available to the target market (Saxon Industries, January 2000).
A thorough write-up, incorporating a clear methodology and formal statistical analysis, is vital. If possible, sound theory should back-up the results of any tests. An initial assessment, by an independent expert, of the method by which the device in question is said to produce the benefits claimed could help determine whether testing is required and, if so, the form it should take.
Last modified : 27 July 2010