SITH Tech Article – Methanol Corrosion of Aluminum

One of SITH Racing core contributions to the performance aftermarket is providing Independent Test and Evaluation support for manufacturers of vehicle aftermarket parts. SITH Racing is the only company that retains a staff of professionals in target key reference areas. In this specific area, SITH racing will utilize it's in-house staff Chemist to scientifically test the effects of long term methanol and water/methanol mixes currently sold by many vendors against aluminum products also developed and sold by vendors. Once SITH Racing completes the testing and validates the outputs, we will post our technical findings.

Many modern motors and components are made from aluminum and aluminum alloys. While weight reduction and durability have proven exceptional advantages for the use of aluminum, there are certain drawbacks. Aluminum and its alloys require a salt called aluminum oxide to remain at its surface for corrosion resistance, durability and longevity. This salt naturally occurs in the presence of oxygen, thankfully there is plenty of oxygen available in today’s internal combustion engines. This salt layer ensures that little to no corrosion occurs and actually hardens the surface of the parts.

Methanol, as well as any alcohol (including ethanol), are weak acids. The alcohols react with the oxide layer of the aluminum and form aluminum methoxide and water or aluminum ethoxide in the case of ethanol. Aluminum methoxide is corrosive and without the oxide protective barrier on the aluminum it begins to degrade. This is a well-known fact by the parts and motor manufactures, they have specifically formulated the aluminum alloy to reduce this occurrence with OEM aluminum parts. The issue becomes with aftermarket parts and custom water/meth kits. Our motors are direct injected so very little alcohol is seen in the top end of the motor. With methanol kits being injected into numerous ports of the turbo, intake, etc. there may become an issue with corrosion.

Aftermarket methanol sold by numerous vendors are of interest as well, they come premixed with water and are usually dyed a certain color. Questions of interest are what type of water are they using? This seems ridiculous at first glance but it will make a huge difference in accelerated corrosion. Tap water contains numerous metal ions like iron, calcium, sodium etc. Mixing these metals with your methanol will accelerate the formation of methoxides. Any water used in the mixing of methanol should be either deionized or distilled which can be purchased at your local grocery or hardware store. Second question is, does the supplier use anti-corrosion agents or metal sequesters? These additives help reduce any corrosion that may occur and if there are any metal ions the sequester makes them inactive.

SITH Racing has begun a methanol degradation test utilizing several aftermarket parts and methanol suppliers. The test will include coated finishes and raw aluminum parts. An apparatus has been made to continually flow methanol over stagnant parts for several time periods. We will measure pitting, and aluminum lose by gravimetric and micrometer. We hope to lay to rest the questions of severity and longevity of aftermarket and OEM parts degradation rate with daily use methanol and ethanol kits.

- Team SITH