Reformulated Gasolines… A report from SEMA

By June 1, 1996, all gasoline sold in the state of California must be of the new "Phase II Reformulated" variety. Basically, the new fuel is similar to the more highly oxygenated fuels which have been mandated by the EPA in several areas of the country during the winter months. It can reasonably be expected that an EPA-spec "phase II" gasoline will eventually be required on a national basis, thus avoiding the need to make such limited changes in specific areas. The main benefits claimed for the new fuel are that the higher oxygen content and lower vapor pressure are supposed to help reduce pollution, while the lower sulfur content is supposed to reduce contamination of catalytic converters.

The good news is that it will probably do all the above. Extensive testing by the oil companies, the automakers and the government has shown that significant reductions in emissions are possible with the new fuels: performance, starting and driveability should be similar for most vehicles newer than the 1980 model year. Perhaps more significant is that these gains will be realized immediately once the fuel is introduced, in contrast to the slow realization of benefits due to new vehicle technologies and/or more stringent new vehicle emissions standards which phase in over a longer period of time due to vehicle turnover. Deterioration of the vehicles due to lack of maintenance can also negate the projected benefits of new vehicle technologies to the point where older, better-maintained vehicles may actually be cleaner even though their technology is less sophisticated.

The not-so-good news is that the cited benefits will come at a cost. The most obvious of these will probably be a slight increase in the cost of the fuel itself. While projections have been made for an up to 10-cent-per-gallon increase, it is generally felt that the actual increase will be less due to market forces. This will be particularly true in areas which already have to use the highly oxygenated winter gas since the cost for making it is pretty close to the Phase II variety. Another cost is that fuel mileage will probably suffer somewhat. The projections are for an average drop in miles-per-gallon of roughly 1 to 3 percent. Naturally, this is highly variable based on the specific vehicle, fuel and driver in question, among other things. Suffice to say that, all else being equal, it is likely drivers will experience some fuel economy loss with the new fuel. Electronically fuel-injected cars with oxygen sensors can compensate better for the new fuel than can those equipped with carburetors.

As can be seen from the statements listed, the greatest concern regarding the new fuel, at least for SEMA members and the automotive aftermarket, will be how it affects older (pre-1980 model year) vehicles, especially those with carburetors. The very extensive testing programs which were conducted regarding the new fuel specification were largely unable, for mostly practical reasons, to test very many older vehicles. As a result, the potential effects are largely unknown since they were not a significant percentage of the test vehicle population. Of the various test fleets involved, Chevron’s consisted of mostly employee-owned vehicles and had the highest percentage of older vehicles relative to the other test fleets. Unfortunately, even this fleet had relatively little representation from per-1980 model-year vehicles. Furthermore, the incidence of fuel-system related problems was higher for the older vehicles when the phase II fuel was used. While such vehicles can normally be expected to have higher component failure rates than newer vehicles anyway, there still was a significant increase in fuel system problems when the new fuel was used.

There may be a very logical reason for this, in the early 1980s, the use of ethanol as a fuel additive became more popular. As a result, most automakers changed the materials in their fuel systems to better tolerate the presence of this alcohol. A common upgrade was to change the nitrile/buna-n elastomer material commonly used in various seals, gaskets and diaphragms, etc., to a more robust viton material. The change in material specifications was also generally carried through to service/rebuild kits as well. Thus, any of the older fuel system components which were rebuilt using a newer service kit should have a reduced likelihood of experiencing a problem with the new fuel.

Testing by GM has confirmed that the older nitrile/buna-n may even be a problem with current conventional gasolines as well as with the new phase II gas. Little has been done about this, however, since it was felt that there are relatively few vehicles still in service which still have these materials present in their fuel systems. As a precaution, Chevron will place a warning on its fuel pumps in California which states that vehicles older than 10 years old and/or those with more than 100,000 miles should be checked for worn fuel system hoses, seals and other "rubber" parts. What this really means is that anyone who has a vehicle older than about 1980 which still has the original, non-rebuilt/serviced fuel systems components on it may have to be concerned about leaks or other problems.

How this will all play out remains to be seen. While it certainly does appear true that the majority of the vehicle fleet will experience relatively little difference with the new fuel, what little data there is regarding the use of phase II gasoline in pre-1980 model year vehicles seems to raise some significant concerns. These may take the form of starting, driveability or performance problems or they may involve incompatibility of fuel system components which may result in leaks. A good recommendation would be to rebuild any original fuel system components using the newer materials, if possible. Otherwise, increased inspections of the fuel systems are probably a good idea so that any problems which may develop can be caught in the early stages, before it gets too serious.

Reformulated gasoline is a very key ingredient in the challenge to reduce air pollution. It offers very real reductions very quickly. For most of the population, it will be a relatively seamless transition with the potential for problems being fairly minimal since the vast majority of the vehicle population consists of vechicles newer than the 1980 model year. It is likely that most people will be more concerned about the potentially increased fuel cost and/or reduced mileage than anything else. Owners of pre-1980 vehicles, however, may have some additional concerns. Upgrading the fuel system components should help avoid anything major from occurring. Hopefully, the CARB projections that such occurrences will be minimal will be correct. In light of all the uncertainty, however, it pays to be cautious.