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There are four main things/chemicals that we can inject into our engine to develop more power - straight water, methanol, a water and methanol blend, and nitrous oxide. We’ll look at the differences between them.
There are three broad categories of things you can do to get more power out of your strip burner’s engine. These are mechanical (new parts like cams and headers), mechanical-chemical (forced induction-superchargers and turbochargers) and purely chemical means (injecting chemicals other than gasoline into the fuel-air mixture). For those of you who want to keep your race car street legal, you’ve got three options - water, nitrous and alcohol, also known as methanol. We’re going to take a look at these three injection liquids and what they can do for us in our quest for more power and speed.
200 PSI water injection kit from AEM Performance Electronics.
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The history of using water injection to increase engine performance goes back to shortly after the beginning of military flight, when aircraft engine makers used it to give their aircraft quick bursts of added power when pilots needed it, like during takeoff or dogfights. Automotive engine makers soon discovered they could also use it to increase the power output of their engines.
Water injection, whether the water spray is injected into the air-fuel mixture in the intake or injected directly into the cylinder, helps to cool the engine. Excess heat is an engine’s enemy. It causes pre-detonation or knock, which hurts power production and damages the engine. The cooling effect derived from water injection cools parts in the air-fuel intake stream, which counteracts knock. This allows us to get more aggressive with our ignition timing profile. It also allows us to bump the boost on our turbocharger or supercharger higher. Finally, cooler air contains more oxygen than hotter air. Oxygen helps the combustion process produce more power.
How does this work, you ask? Fire doesn’t like water, so how can an engine work if you inject water into the combustion chamber or the intake? Water injection uses the principle of absorption to increase power output and protect your engine. Since water has a fairly high coefficient of heat absorption, when it’s sprayed or misted into the intake or the combustion chamber, it cools everything it comes into contact with as it evaporates.
Thus, by the time the air-fuel mix is ignited, all that’s left of the injected water is vapor-steam. Steam doesn’t hinder combustion much. The little that it does also helps the engine produce more power by ensuring that the wavefront of the flame in the combustion chamber moves evenly across the combustion chamber, also making sure the engine doesn’t knock and maximum power is produced throughout the combustion cycle. Research has shown that an injection ratio of about 15 percent injected water by mass achieves the maximum cooling effect on the air-fuel mixture and the internal engine components to deliver the maximum performance gains. The main problem with purely water injection kits is that they’re difficult to find. You’ll most likely need to buy a water/methanol injection kit and fill the supply tank with straight water instead of water and meth.
AEM Performance Electronics water-methanol injection kit for injected engines with forced induction.
Image credit: www.aemelectronics.com/sites/default/files/aem-wmi-gas-header.jpg
Water/methanol injection gives you the benefits of water injection outlined above, plus the benefits of increased octane. Increased octane gives you two benefits. The first is increased power from your engine. The second is increased resistance to knock. Some people call water/methanol injection (also known as alcohol injection) “the poor man’s racing fuel.” This is because the benefits mirror those of something like 100 octane racing fuel, but you’re paying about a third for the water/methanol mix of what you would for a good quality racing fuel.
ProMeth water-meth injection kit with three quart supply bottle.
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Water/methanol injection works to benefit horsepower and torque production in several ways. First, the water absorbs heat in the air charge and the engine, making the engine run more efficiently and boosting the density of the air charge. Denser air has more oxygen, and air with more oxygen produces more power. As mentioned above, lowering the temperature of the engine and air charge allows you to utilize a more aggressive timing profile that would normally cause the engine to knock.
Snow Performance Boost Juice™ water-methanol mix.
Image credit: http://www.snowperformance.net/Snow-Performance-Boost-Juice-p/40008.htm
Higher octane fuel works in two main ways. First, it allows the fuel to burn more completely and evenly, decreasing engine knock. Because the fuel is burning more efficiently, the engine can produce more power and torque. As with water injection, this allows for a more radical ignition timing profile, which helps your engine develop more power. The lower overall temperatures also allow you to increase boost from your supercharger or turbocharger system, thus increasing the horsepower and torque gains from the water/methanol injection alone.
Snow Performance Boost Coller Stage 2 water-methanol injection kit.
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The main drawback to water/ethanol injection is that most kits on the market come with small one-gallon tanks for the solution. Serious engine damage can result if this tank is allowed to run dry. You can combat this by substituting a larger tank. Most manufacturers of water/methanol injection kits have built in engine protections to their controllers.
The first type will trigger a light in the driver compartment alerting you that the tank is running low or about to run dry. More advanced engine protection features act like a failsafe. These will shut the system down and cause your engine controller to revert to a safer mapping to prevent engine damage. You can also use a simple switch to toggle the meth injection on and off and switch between “normal” and “injected” maps. Depending on your engine and the overall tune you use, you can expect power gains of up to 20-30 percent using water/methanol injection.
Holley/NOS 02001NOS “Cheater” Nitrous injection kit for carbureted engines.
Image credit: rspimages.holley.com/02001nos.jpg
Nitrous injection has two main camps: Those who love it and those who hate it. When done properly, it can give you huge performance gains. When done incorrectly it can cause your engine to explode due to greatly increased combustion chamber pressures. For street use, I think the best thing that can be said about nitrous injection is that you can buy injection kits that will deliver modest horsepower gains of about 25 50 horses and you can buy kits that can deliver gains of up to 400 horses and more, depending on the size of the engine and the amount of nitrous being injected.
Unlike methanol/alcohol, nitrous isn’t flammable. When injected into your engine, the engine’s latent heat breaks down the bonds between the nitrogen and oxygen, releasing more oxygen into the combustion chambers, allowing for more complete and efficient burning of the air-fuel mixture. This allows you to increase the amount of gas being sent to the engine, which in turn increases the amount of power the engine produces. Like methanol and water, nitrous injection also cools the intake and incoming air charge, which makes for denser air, allowing for radical ignition timing and thus more power.
Holley/NOS Nitrous System Universal universal nitrous oxide injection kit PN 0513NOS Image credit: rspimages.holley.com/medium05130nosv3.jpg
I’m one of those who don’t really like nitrous, because it’s not a “plug and play power adder” the way water and methanol are. Nitrous requires some pretty hefty engine modifications before you can start using it all out. Sure, you can install a small kit that will give you 15-25 horsepower gains, but we’re looking for bigger gains in our strip burners. 15-25 horse improvements are great for red light warriors, but drag racers need more.
Holley/NOS GM LS1 EFI Nitrous System for fuel injected LS1 engines. This kit is fully adjustable and designed to deliver up to 200 HP gains. PN 05168NOS
Image credit: https://rspimages.holley.com/large05168nos_jpg.jpg
This is true even for the “run what ya brung” type of drag racer, the guy who takes his daily driver to the track and runs a few passes every weekend. This guy’s going to have to pull his heads and lower the compression ratio of his engine. If this isn’t done, he can melt his valves and/or pistons, or blow his head(s) clean off the engine.
Haltech makes excellent tuning software that doesn’t take an engineering degree to learn quickly.
Image credit: www.haltech.com/wp-content/uploads/2011/01/article_ecuman.jpg
Whether you choose straight water, straight methanol, a mix of water and methanol or nitrous, you’ve got to take your car to a reputable tuner or buy and use a piece of quality engine tuning software. No matter which way you choose, it’s also a good idea to get yourself familiar with engine tuning tables and timing maps. My recommendation is to find a tuner in your area who will teach you how to make engine map adjustments on the fly so you can assure yourself of the biggest gains possible, because the temperature and relative humidity are never going to be exactly the same twice and these have huge impacts on how your engine runs.
