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E85 materials compatibility

This article explains the effects of ethanol / E85 on common race parts and our recommendations on how to deal with the unique characteristics of ethanol blend race fuels. Includes answers to FAQs about fuel cells, storage, and other related questions.

E85 materials compatibility

The challenge with this topic is that E85 has only been commonly used in motorsports for a few years -- a very short time compared to gasoline. There is little information about long term use of high percentage ethanol blends in a race environment so our information is based on shorter term data collected from our use and from our customer’s feedback.

When E85 first started to make its appearance in a few cars at drag strips in the Midwest 5-7 years ago the fuel was mainly treated like methanol (E85 is alcohol too right?), but over time racers discovered that the corrosion problems they used to have with methanol didn’t seem to be an issue with Ethanol / E85. The common misconception about Ethanol being corrosive still persists in the racing community today.

The fact of the matter is that uncontaminated ethanol is not corrosive. However, Ethanol is hygroscopic in nature and is capable of absorbing large amounts of water. When ethanol based fuels become contaminated with significant amounts of water (over 2% by volume) the formation of mild organic acids can occur. Formic acid, acetic acid and other compounds can adversely affect soft metals like aluminum, zinc, brass, and copper causing a white powdery residue.

The solution is simple – keep your fuel dry! Seal drums of fuel by removing the pump and installing a plug. Keep your fuel cell or tank full if not in use. Pick materials to use in the fuel system and engine that are corrosion resistant. It’s that simple to use E85 without any adverse effects.

One of the questions I get the most from racers that call Horsepower Innovations is about specific parts compatibility with E85. So what I have done below is compiled a list of those specific questions I get the most along with the results of some testing we have completed on specific materials. This information is in no way intended to be authoritative or replace information provided by specific manufacturers and is intended to be general in nature (not typically product or brand specific). The information below is based completely on our experience and feedback from our customers.


Will my fuel cell and foam be OK with E85? 

We have not had any reports of a fuel cell (aluminum or plastic) that has had issues with E85 -- including the foam. However, that does not mean it isn’t possible to have an issue (especially with uncoated aluminum). To avoid any problem we recommend storing the vehicle with the tank either completely full or completely empty. In moist environments, it is also important to seal the tank vent to prevent moisture from being absorbed from the air. 

Fuel cell foam is a loaded question. On one hand the best bet to be certain the foam will not breakdown is to remove it; however, fuel cell manufacturers put the foam in the cell for a reason – crash protection. We recommend that you contact the cell manufacturer for specific guidance on fuel cell foam compatibility with ethanol and the safety considerations if removing it. Fuel cell foam will break down over long periods of time regardless of what fuel is used and eventually needs to be replaced.

Will braided lines be OK with E85? 

While long term life may be slightly reduced with E85 (we don’t know yet!) all common brands seem to be compatible with E85. The OEMs have been dealing with 10% ethanol in fuels since the early 80’s and appear to be producing parts that are not sensitive to ethanol. 

Most braided line in sizes commonly used for fuel systems in motorsports are designed for pressures many times higher than the application. For example, Aeroquip advertises their braided line from -4 to -10 AN as being rated at 1000 psi with their stated test pressures 2 to 4 times the advertised rating. Talk about over-kill! 

One common complaint about braided lines when used with any fuel (especially gasoline) is that vapors often escape through the hose. I do not expect this to be any different with E85, although the smell seems to be somewhat less with E85 than with gasoline.

Are hard aluminum fuel lines OK with E85? 

Again, this is a part that we have had no issues with. Testing for 3 years has shown zero corrosion on the inside of ½” Russell aluminum line. Cutting used line open at bends and straight portions shows a “like new” surface inside. We expect that IF there is a leak in the line it would allow air and moisture into the line and it would show corrosion. Steel lines have not been an issue either, other than the fact that ethanol seems to clean up any sludge or residue left from gasoline which may clog fuel filters a time or two until it is all gone.

What about the inside of carburetors? 

With regular usage we have seen no corrosion on the inside of carburetors. This includes both zinc and aluminum castings. If a carburetor is allowed to sit for extended periods of time with the bowls full some oxidation may occur (more so with uncoated aluminum main bodies than with zinc castings). We have seen some accelerator pump needles stick when left sitting for a long period of time. Both scenarios can be corrected with an oil-based cleaner like WD-40. 

For winter or long term storage we recommend that you drain your carburetor by removing a bowl screw and draining the fuel from the bowls into a cup. Work the accelerator pumps until they are empty. Then spray some WD40 into the vent tubes and onto the throttle shafts. Actuate the accelerator pumps then use a couple short burst of compressed air into the vent. This will coat and protect the inside of your carburetor. Incidentally, we recommend the SAME procedure with a gasoline carburetor which can leave significant deposits and gum after sitting a long time with the bowls full.

What bowl and metering block gaskets do you recommend? 

We recommend only the Holley brand light blue re-useable gaskets with your Horsepower Innovations carburetor. Other brand gaskets have on rare occasion (especially the dark blue colored ones) bleed blue dye into the carb. We also recommend any of the black carb base gaskets; avoid any blue carb base gaskets (they stick!). We believe that some gaskets are just plain better than others – any gasket issues seem to be gasket quality related, not fuel compatibility related.

Are clear screw-in site plugs OK with E85? 

Yes, but only use these only as a temporary way to check or set your float levels; reinstall the brass site plugs when your float levels are set. The clear plastic screw in site plugs turn cloudy and get rubbery after a short time. This is also true with gasoline! They just do not hold up and are prone to breaking off in the float bowl. If you really want clear site plugs in your carburetor, Horsepower Innovations now offers bowls with built in windows as a standard feature with our new carburetors and can upgrade our older carbs.

What epoxy do you recommend with E85? 

We do not recommend ANY brand epoxy for use with E85 when in a submerged environment. Alcohol is often listed as the clean up agent on the epoxy instruction labels and does not hold up well when submerged in alcohols. That being said, JB Weld seems to work well with E85 when not submerged for long periods. If you have a damaged part that requires repair please contact us and we will work on getting you a new part as inexpensively as possible instead of repairing with epoxy.

What fuel pumps, regulators, and filters are compatible with E85? 

To make 100% certain please contact the manufacturer of the pump you are looking at. That being said, most of the higher quality billet aluminum pumps have a hard anodized coating and are compatible. We have had good luck with Aeromotive, Mallory, and Magnafuel pumps. The later high end Holley pumps are also very good. Watch for pumps with seals that are advertised as alcohol compatible with nylon or stainless gears or vanes. These are a “slam dunk” since methanol compatibility is a much harder standard to achieve than E85 compatibility. If it’s methanol compatible it is definitely E85 compatible; if its gasoline compatible it is probably OK but no guarantees! 

The same holds true with regulators. The billet aluminum ones are usually hard anodized and hold up very well. Make sure that any o-rings are compatible by checking with the manufacturer. Again we have had good luck with the Aeromotive, Mallory, and Magnafuel. The diaphragm in the old style dead-head cast grey Holley regulator does NOT seem to hold up well long-term. 

The best filters seem to be the stainless steel mesh type. A few customers have had good luck with the paper canister style filters, but if you are starting from scratch look into the stainless mesh types. Cheap paper filter cartridges may not hold up well with any fuel (gas or E85) and may have glue holding the paper to the cartridge “end” that may not be compatible with ethanol and will disintegrate over time (you may not notice an issue, but you won’t be efficiently filtering your fuel). It is a good idea to change or clean your fuel filter every year to make sure you do not start the race season with a partially clogged filter.

What about internal engine parts? 

Internal engine parts have been surprisingly clean when the engine is run only on E85. The lack of carbon deposits on the top of pistons and cylinder head chambers is remarkable. Spark plugs stay cleaner longer and so do oxygen sensors. Some fleet vehicle studies have shown no excessive wear over hundreds of thousands of miles on E85. Bearings on our own test engine after over 5,000 street miles and 500 passes looked like new and were re-used when the engine was freshened.

Should I use Top Lube with E85? 

NO! It may not hurt anything, but some top lubes have been known to settle out in the bottom of the tank over time clogging filters and carbs. It is not necessary because the >15% gasoline content in E85 is sufficient to lubricate upper cylinders. If you want your exhaust to smell nice, the scented additives intended for methanol seem to work just fine with E85 when used in moderation.

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