Additives For Fuel Economy Fuel Additives Additives are a great source of controversy, there are commercially available additives but the ones you'll probably hear the most about are "home brewed" Most of these revolve around Acetone, Toluene and Xylene, and typically call for a cocktail mix of one or more of these chemicals. Xylene and Toluene appear to be fairly innocuous when added in small doses to your gasoline. Most Octane boosters use one or the other to increase the octane of your gasoline. This is and of itself will not lead to gains in MPG, it's possible that these additives will allow the fuel to burn more efficiently but I have not been able to find any published studies that either support or refute that theory. Acetone is one of the most heavily recommended fuel additives to increase your fuel economy. Do an online search on acetone as a fuel additive and you'll see what I mean. Supposedly acetone will increase your fuel economy by reducing the surface tension in your gasoline. This allows the gasoline to more completely vaporize and results in a more efficient combustion with more of the gasoline being consumed and less going out of the tailpipe. Some additional benefits of Acetone as a fuel additive are that it increases octane, since it is a solvent it helps clean your fuel system. The negative (claims) are, that it will corrode your fuel system and eventually cause your injectors and Fuel pumps to fail, it will attack gaskets and related components also causing them to fail. I have not been able to find any documented studies that support either side of the argument one way or the other. I am still intrigued by the possibility of using one of any number of recipes that are out there but am more concerned of any potential damage that additives may cause. I'll probably end up trying the additives at some point in time but it will probably be one of the last things I do. The one good thing of an additive is that it's a lot simpler to remove then complex modifications, just stop adding it to the fuel tank! If any readers have experience or information with additives as they relate to fuel economy please post it in the forum and share it with us. Engine Oil and Transmission Fluid Additives There are numerous additives available for both engine oil and transmission fluid that should help in increasing your fuel economy. Most, if not all of these are aimed at reducing friction between moving parts in your vehicles engine and transmission and extending the life of these major vehicle components. The reduced friction should, in theory, also assist with increasing your Fuel efficiency. There are four basic types of oil additives, PTFE Moly or Molybdenum disulfide Chlorinated Paraffin Solvent Based Each of these has their pros and cons. PTFE has a reputation of clumping together and clogging oil filters and or other oil passages. As a matter of fact that is the basis as to how it works, it will bond to a surface and it's lubricant properties will reduce the friction that the surface is ordinarily exposed to. However when that surface is an oil passage or filter then the result can potentially be clogging of that area. Many of the references I have been able to find on PTFE based additives are of a negative nature and overwhelmingly advise against using them. Molybdenum disulfide also called Moly or MoS2 has many of the same properties as PTFE. It is a naturally occurring mineral that is ground to sub-micron particles where they can be used as a "super" lubricant. Moly literally fills the valleys and voids that can be found on all machined parts and provides a smoother surface, the layer of moly also acts as a lubricant. It typically take 500-600 miles to build up this layer of moly. Some of the claimed benefits of Moly over PTFE is that it has a high temperature rating (2000°F) vs PTFE which turns into a noxious gas at 600°F, has a very high pressure rating (400,000 PSI vs 350-450 PSI for PTFE) and that it has a consistent particle size, which prevents clumping and potential blockage of oil passages. The majority of the references I have found on Moly as an oil additive are fairly positive. It has several advantages over PTFE. The only potential problem with Moly that I have found in references is that is may settle to the bottom of the engine. There are brands available that use a finer particle size of Moly to overcome this and other brands that claim they have a "soluble" version of moly (I believe that claims to soluble moly are in reality a finer particle size which should keep it in suspension longer). Chlorinated Paraffin is another additive that can be found in many aftermarket additives. If you have ever gotten Chlorine bleach on your fingers and rubbed them together you have noticed that it feels very slippery. The chlorinated paraffin additives work on this principle, the paraffin acts as a carrier for the Chorine. There are many negative references to this, the chief complaint being that additives with chlorinated paraffin's eventually break down into acids (Hydrochloric acid being the most prominent). The acid attacks the metals in the engine, and will supposedly break it down leading to failure from metal fatigue. Interestingly enough I have not been able to find one single case of engine failure attributable to this, there are numerous articles and forum posts on why it is "Potentially" bad for your engine. I'll have to confess that I have been using a Chlorinated Paraffin additive on all of my vehicle (XR-1) for the last 10 years or so. My experience has been overwhelmingly positive, I have never had an engine fail to due internal metal fatigue, I have a tendency to put a lot of miles on my vehicles and am inclined to believe that I have benefited from using the XR-1 additive. The fourth category is the solvent based oil additives. There are a number of additives that use solvents (mineral oils, xylene, naptha, acetone and toluene to name a few). I'm not sure why adding this to the oil is beneficial to running the engine. Any solvent that thins the oil will breakdown the oil barrier between moving metallic parts! This results in a loss of lubrication! I would stay away from these with one exception. Using a solvent based additive just prior to an engine oil change may be beneficial in helping clean out sludge deposits in your engine, the only risk you run though is that you may not entirely get rid of all of the solvent before adding fresh oil. There are other oil additives beyond the four main categories we have just visited. Zinc and Graphite are also the bases of some additives that are available on the market. I have found few products that contain them and not much reference, positive or negative on graphite. There is significantly more information on Zinc, but not as a consumer additive, Zinc is already present in most engine oil formulations and is universally accepted as a superior lubrication enhancement. The true question as to whether adding it in the quantities you find in oil enhancers is good for your engine or not and more importantly, will it help you save on fuel costs by increasing your fuel economy. In summary; to date I have not found any conclusive studies or evidence that support oil additives having a significant impact on fuel economy. There are significant debates on the benefits vs. potential harm that they may cause. Personally I have been using a Chlorinated Paraffin additive for many years now with no negative effects and potentially positive results in terms of engine wear and potentially fuel economy. Out of the additives I have researched, Molybdenum disulfide appears to be the most promising, with the least amount of critics and the most amounts of positive write-ups. I will probably be conducting some experiments in the future comparing the Chlorinated Paraffin, Moly and no additive options to see if there is any perceptible impact on Fuel economy. Stay tuned as I'll post the results on this website as well as the forum. If you are interested in more information on oil and oil additives for your vehicle I would reccomend this website, Bob is the Oil Guy. This site is a comprehensive source of information on vehicle lubrication and additives.