E85 Vs. Water/Methanol Injection: Which Should You Run?

Since the inception of the internal combustion engine, knock has been the destroyer of worlds— especially if you have a stock bottom end. Thus the never-ending quest for a more knock retardant fuel is almost just as storied. When lead was discovered to be an anti-knocking agent in the 1920s, it was immediately implemented into gasoline (or petrol, depending on where you’re from). But in the 1960s lead was outlawed due to its environmental impact. However, other technologies existed at the time that were just as—if not more—effective at preventing knock and quickly became popular in high horsepower applications; enter water/meth injection. Ethanol, on the other hand, is a relative newcomer by comparison but offers a lot of benefits that appeal to racers everywhere. But do you have to choose one or another? And, if so, which is best?

In an effort to help you make more of an educated decision when choosing between E85 and water/methanol injection, and what situations they are each best suited for, we turned to a panel of tuning, E85, and water/meth injection specialists to answer our burning question, they include: Matt Snow, proprietor of  Snow Performance, Chuck Anders, founder and head tuner at Houston House of Power, and Jason Rueckert of VP Racing Fuels . But first, a little background.

War Emergency Power

In the 1940s, during World War II, water/methanol injection was introduced (like many go-fast parts we use today) in aviation applications. In those instances, water/methanol injection was used to increase power in airplane engines for high stress situations such as take off, enemy evasion, or during dog fighting. But much like technologies such as nitrous and super/turbochargers, servicemen came home and began experimenting with them on their hot rods.

What Are Your Options?

Fast forward to today and the increasing popularity of boost. There is no doubt that power adders of every kind have become increasingly popular, not only on track cars, but from original equipment manufacturers as well. But, with increased cylinder pressures comes the increased chance for knock. You can combat that in part by running a higher octane fuel, but eventually you run out of room at the 91 (or 93 if you’re on the east coast) octane limit. You can jump up to race fuels but not only are they substantially more expensive, some are not very catalytic-converter friendly—that is if you’re still running them. So where does that leave you? Well, you realistically have two choices if you don’t want to run race gas: E85 or water/meth injection.


Kyle Brixey’s Trailblazer SS is no stranger to boost.


Since the advent of E85 in the early 2000s, people have been using it as go-fast juice due to its intrinsic knock resistance and cooling properties. Basically, E85 is cheap race gas. Many say it is equivalent to 105-110 octane, meaning it has much higher knock-resistant properties than pump gas and is usually substantially cheaper. However, there is is also more to it than just that. Ethanol has a cooling effect on the intake charge and burns at a cooler temperature as well— decreasing the chances for hot spots and thus pre-ignition. While gasoline does have a slight cooling effect as well, ethanol has an even greater effect due to its evaporative qualities. Currently, up to 10 percent of the pump gas you are already putting in your daily commuter or racecar is ethanol too. In fact, even some racing fuels marketed to late model streetcars contain ethanol.


This Cadillac CTS-V makes almost 750 horsepower on E85 .

While ethanol is great for the qualities previously mentioned, it is far from the perfect fuel. It is very hygroscopic, meaning it has a great propensity to absorb water. That means it is typically more corrosive in any given fuel system— this leads to more maintenance and possibly replacing components more often, if you’re not careful. It also contains 30 percent less energy than gasoline. In other words, you will have to flow and burn 30 percent more of it to keep a mill fed— usually requiring the entire fuel system to be modified and upgraded.

Also, though E85 may be readily available at a gas station near you, that doesn’t necessarily mean you will be so fortunate in areas outside your neighborhood. While some gas stations carry E85 these days, there are substantially more that don’t. For example, there is only one gas station in the entire state of Utah that offers E85–one. So, if you decide to run your car on E85, and plan on driving it on long trips, you will have to map your route carefully, or find local speed shops that keep it on hand. Storing it yourself can be problematic as well, since, as we previously mentioned, it is very hygroscopic and will absorb water easily. Your car will also need to be custom tuned to run the corn-based fuel. This, among other factors, makes switching back to gasoline fairly complicated— at least at the drop of a hat. One solution to this is a flex fuel sensor which makes running any combination of ethanol or gasoline a breeze, but we’ll get more into the specifics of running one another time.



So you want the benefits of a more knock resistant fuel, but you don’t want the headache of switching out your fuel system, running custom tunes or mapping your driving route so you don’t run out of fuel? Or do you just want additional cooling? Then you may want to look at water/meth injection.

procharged race motor w WM

Notice the water/meth injection nozzle mounted to the intake elbow of this ProCharged brute.

As we mentioned before, water/methanol injection has been around since the 1940s but has become very popular recently due to the proliferation of power adders. In essence, a water/meth injection system activates at a predetermined RPM and provides the engine with a cooling mist of either straight water, straight methanol, or a combination of water and methanol.

As the water (or combination) is heated in the combustion chamber it evaporates, taking heat with it. This cools the cylinder and prevents any hot spots from forming, thus preventing detonation. But why run it in a combination with ethanol or methanol?

While methanol does have lower energy content than gasoline, it typically adds slightly to a cars power level, especially when you consider the fact that you can run more ignition timing without detonation due to the cooling effects. However, since it has a higher latent heat of vaporization (meaning it requires more energy to evaporate and thus does so more readily and at a lower temperature) than gasoline, it has increased cooling properties. Its chemical make up also carries addition oxygen molecules that are freed when it is converted to a gas, aiding in combustion.


Dual water/meth injection nozzles keep everything cool and knock free.

Methanol is also readily available in the form of windshield washer fluid, or is available for purchase in pre-mixed bottles (or full strength) from vendors for around $10 a gallon–we recommend getting it from a vendor, but to each his own. Windshield washer fluid is typically a mixture of methanol and water and has a higher methanol content depending on what it’s freezing point is. For example, washer fluid rated to -20 degree temperatures typically contains a 30/70 methanol to water mixture. As mentioned before, the lower the freezing temperature rating, the higher the methanol content.

Methanol has the added benefit of not only cooling the cylinders due to its rapid evaporation, it also contains more oxygen than gasoline and thus has some power adding capabilities— though they may be slight, but is typically the preferred liquid to use in an injection system.

Depending on a given combination, mixtures can vary from 30-50 percent methanol to water content–however, many choose to run straight methanol to maximize the increases in power and cooling we previously mentioned. In addition to cooling the combustion and intake charge, the water/meth system also removes carbon deposits from inside the motor, a win-win if you ask us.

However, methanol is incredibly corrosive and can break down components–even ones design to work with the solution–incredibly quickly. That is why it is typically run in a mixture with water, to mitigate the corrosive effects of the ethanol.

How Alcohol Cools

Both ethanol and methanol are both alcohols, albeit ones with different chemical structures. However, they both use a similar process to cool down an incoming intake charge. Both compounds have a higher latency of heat than gasoline, meaning they require more energy to evaporate or change state from a liquid to a gas. Since they require more energy to change states, they absorb the heat energy around them, thus cooling things down.

It is this change of state that pulls energy from the air. Think about it this way, if you put alcohol on one of your arms, the alcohol feels cool to the touch–that’s because it is. As the alcohol rapidly evaporates, it takes energy with it. This leaves everything around it cooler, including your skin, as it sucks energy from its surroundings to evaporate.


“Any time you look at thermodynamics, evaporation is always a cooling process,” said Jason Rueckert of VP Racing Fuels. “You get a large cooling effect from absorbing heat from the cylinder and then, in my opinion, you get probably an equally large cooling effect just from that massive amount of alcohol evaporating since engines that run it need much higher quantities of it–combine the vaporization of the fuel with the greater amount of fuel and you have a huge cooling effect.”

Which Should You Choose?

For the answer to this we turned to a couple of guys who are vastly more experienced with both the use of Ethanol and Water/Meth. We hit up Matt Snow, owner of Snow Performance, who’s company specializes in water-methanol injection kits and Chuck Anders, of Houston House of Power, who builds and tunes high-horsepower applications on the daily–many of which run either E85, water/meth, or both.

Snow and Anders both told us that they had recently seen an influx of customers who are seeking kits to run on their ethanol-powered vehicles.

“E85 has really blown up,” Snow said. “However, sometimes the quality of it is somewhat questionable, a lot of people are worried about their tune on say an old tank of E85, or even new, since these days you don’t know 100 percent of the time what quality of E85 you’re getting.”

Stage-3G controller

Snow’s water/meth controller ensures that, on the rare occasion that you have a problem with the pump, you are aware of the problem and can even pull out boost to keep the motor safe.

Snow says that despite even the best efforts of companies, as it ages, E85 typically has different concentrations of gasoline to ethanol, sometimes as low as 60-70 percent ethanol content. This can be dangerous when you are banking on ethanol’s anti-knock qualities to keep your engine safe–not to mention precise fueling since ethanol packs less of a punch than gasoline.

Instead of being able to tune the car for the 105 octane that it should be, they have to tune it down to say run on a 97 to 98 octane level— meaning they’re leaving power on the table.– Matt Snow, Snow Performance

“If you don’t have a content sensing device, you typically have to tune for the lowest common denominator to keep it safe,” Snow said. “Instead of being able to tune the car for the 105 octane that it should be, they have to tune it down to say run on a 97 to 98 octane level— meaning they’re leaving power on the table.”

In essence, unless you want to be checking every tank of E85 for its ethanol quality and adjusting the tune accordingly, or are running a flex fuel sensor, it might be a good idea to run the corn-based fuel and water/meth in tandem. Not only does the water/meth provide more than enough room to compensate for any variation in fuel quality, it allows even more timing to be thrown at the car which equals power.

Anders, on the other hand, felt that running the two in tandem was more about trying to safely extract every ounce of power an engine has to offer, rather than worrying about the quality of E85 you are getting.

“The combination of both E85 and water/meth will each add to increasing octane levels and cooling effect,” Anders said. “You’re really getting the best of both worlds if you have both. Methanol and ethanol are really similar, especially when it comes to their octane rating and cooling effect–although neither technically have an octane rating, but it is comparable to around 110–so if you spray methanol on top of 93 pump gas, you’ve still got around 80 percent regular gas, so the effect isn’t as great as if you were running ethanol in the tank and then multiplying it by adding the methanol on top–which is really the best of both worlds.”

If you spray methanol on top of 93 pump gas, you’ve still got around 80 percent regular gas, so the effect isn’t as great as if you were running ethanol in the tank and then multiplying it by adding the methanol on top–which is really the best of both worlds.- Chuck Anders, Houston House of Power

Anders mentioned that flex fuel sensors are so easy to install and run these days that it doesn’t make a lot of sense to not utilize one if you are going to make the switch to E85. And while there may be some inconsistencies with ethanol content when purchasing  from gas stations, the swing isn’t as large as you would think.

“You don’t see a huge swing when going from 60 to 80 percent ethanol from a tuning standpoint honestly,” Anders said. “You don’t want to run a 60 percent mix if you don’t have to, but it’s very close to being what you’re going to be able to run timing wise if you were seeing almost pure ethanol. The inconstancies at the pump are talked about but it’s not as necessarily critical as many think–unless you’re not running a flex fuel sensor, but that isn’t happening much if at all with how easy they are to run with most GM and Ford applications.”

Both agreed, however, that after justifying the expense of making the switch over to E85, the cost of a water/meth kit can be a drop in the bucket and good insurance in case of a bad tank of corn, or will allow you to push the limits of your build to the ragged edge with considerably more reliability than a system running purely on pump gas or E85 alone.


“We’re getting more and more calls from people who are running E85 but want to run water/meth as an insurance policy,” Snow said. “Otherwise the tuner has to let them out with a somewhat neutered tune that is a little better than pump gas, but they just spent a ton of money on this conversion to E85.”

Snow says that they have logged data from three separate cars running his water/meth kits on top of E85 and they are typically seeing an increase in power of 5.5 percent. That may not seem like much, but on a high-horsepower application, that can amount to as much as 50 horsepower at the wheels, if not more.

Anders agreed that the increases from methanol can be substantial and added that he has seen massive gains from the use of direct port water/meth on an application that had already been running E85 and water/meth from the get go.

“I’ve done plenty of testing and water/meth definitely has been a critical factor in a lot of builds,” Anders said. “I’ve seen on some setups, even ones already running E85 and water/meth, just going from a single nozzle in front of a throttle body to a direct port meth kit gains as high as 20 horsepower. There are definitely benefits both ways and running them together is certainly something I entertain all the time–it’s hard to beat.”

Water/meth attains these gains by not only allowing the timing to be advanced aggressively, but by also cooling the intake charge down massively and adding oxygen to the mix on top of everything else—even when compared to the E85 alone.

“Where most of it comes from is cooler air charge,” Snow explained. “At 18 pounds of boost we are pulling out an additional 60 degrees from the intake charge.”


This Snow Performance water/meth kit comes with everything you need to install and monitor your new system on a fifth-gen Camaro.

While running E85 by itself may allow you to keep the timing up in boosted applications, it won’t cool the intake charge like water/meth will. Running the two in tandem can be a winning combination that will not only keep an engine happy in high-boost applications, but can ensure that the engine is producing the most horsepower it is possibly capable of making.

With E85 and water/meth there is no spark knock,there isn’t even the chance of spark knock since that flame is controlled so well.– Matt Snow

“With E85 and water/meth there is no spark knock,” Snow said. “There isn’t even the chance of spark knock since that flame is controlled so well.”

When it comes right down to it, the decision is yours. While both have their merits, it doesn’t mean that you can only choose one. A $400-600 kit is incredibly cheap insurance, considering the cost of the rest of the components at risk, and can be quite the combination when run in tandem with E85. Whether you use water/meth as an insurance plan, or use it to turn your build all the way up, you can’t really go wrong using both to get the most from your setup.

Article Sources

About the author

Chase Christensen

Chase Christensen hails from Salt Lake City, and grew up around high-performance GM vehicles. He took possession of his very first F-body— an ’86 Trans Am— at the age of 13 and has been wrenching ever since.
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