Alternative Fuels and Additives 9.1 Do fuel additives work?
Most aftermarket fuel additives are not cost-effective. These include the octane-enhancer solutions discussed in section 6.18. There are various other pills, tablets, magnets, filters, etc. that all claim to improve either fuel economy or performance. Some of these have perfectly sound scientific mechanisms, unfortunately they are not cost-effective. Some do not even have sound scientific mechanisms. Because the same model production vehicles can vary significantly, it’s expensive to unambiguously demonstrate these additives are not cost-effective. If you wish to try them, remember the biggest gain is likely to be caused by the lower mass of your wallet/purse. There is one aftermarket additive that may be cost-effective, the lubricity additive used with unleaded gasolines to combat valve seat recession on engines that do not have seat inserts. The long-term solution is to install inserts at the next top overhaul. Some other fuel additives work, especially those that are carefully formu
