Alcohol/Water Injection
Want to run 5-10 PSI more boost then you are now? Sure you do, unless of course you’re opposed to adding 50-100 hp to your car. With alcohol injection you can do just that, all while buying your gas from the pump. I’ve been a huge fan of alcohol injection for many years now. Personally, I don’t see why everyone isn’t running some type of supplemental injection nowadays. Not having to pay outrageous prices for race gas will pay for your kit within the first year. To give alcohol injection its proper recognition, we’ll need to discuss a few things first.
When I say alcohol, I am referring to the chemicals in that category as a whole, such as Methanol, Toluene, Benzene and Ethanol to name a few.
I’m going to use 91 octane pump gas as an example since that seems to be the highest and most available nation wide. When increasing the boost on a vehicle that is forced induction from the factory, we are essentially increasing the compression of the motor. So what determines the amount of boost we can add before the motor goes pop? Here in lies the octane to compression threshold. If you add boost, you need to add fuel. That part is simple, more air requires more fuel. The entire theory on making more power is based around this ideal. So why can’t we just install huge fuel injectors and run 30 psi? Because every fuel has a point where it auto ignites and 91 octane reaches that limit far before we ever see that 30psi. .
With that in mind, we can look at the benefits of alcohol injection. The biggest reason alcohol injection is effective, is the increased octane it has over 91 pump gas. Let’s use Methanol as an example. Methanol has a octane rating of 105. So when Meth is sprayed into the intake either before the throttle body or in a direct port system, it effectively raises the octane of fuel that is injected into the combustion chamber. There are several very good chemicals that can be used for this. Methanol is definitely one of the more popular ones, but you can use Denatured Alcohol, rubbing alcohol, Ethanol, E85, Toluene or any of those mixed with water. Water in itself IS NOT a means to increase your octane. However, when injected into the motor, it evaporates upon entry into the combustion chamber effectively reducing the combustion temperatures by up to 300* F. I’ll go into water injection in more depth later so as not to confuse the two different types of tuning involved. The above listed chemicals all have different octane ratings, so each will require tuning if you change between fuels.
Before we can really get into tuning and the effects of the different chemicals we can choose from, we have to understand the various injection options available to us. There are literally tons of options available today, ranging from DIY setups consisting of a spray nozzle, pump, fuel line, pressure switch and reservoir all the way to $1000 setups that are closer to running a full standalone computer. It’s up to the individual what avenue they choose for themselves based on budget and power goals. I’ll explain the most common setup’s used today and the tuning involved with each in a later installment.
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