Posted By RichC on July 6, 2012
Hmm … would be interesting to try this on a VW TDI diesel?
Diesel engines are the perfect recipients of mild engine modifications. They are considerably robust—generally much more so than gasoline engines. Without going into a diesel history lesson, this is what led to the diesel mod craze in the first decade of the 21st century.
Quadruple-digit power numbers were actually obtainable to any diesel owner who was willing to shell out enough dough. But, as many diesel hot rodders will tell you, there is a price. Blown head gaskets, melted pistons, burned-up turbos, and destroyed fuel injectors can be real downers when you have an expensive diesel under the hood. Higher temperatures and increased pressure within the cylinder walls are generated in conjunction with more power, and if you cannot keep the engine cool and together, than you’re going to have either catastrophic failure or at the very least premature wear.—
01. The MPG-MAX kit comes with three injectors. One has a small nozzle that is fed by the electric pump as soon the system activates (usually around 6 psi unless programmed otherwise). The other two can be fired at the same time using a T-fitting after the supplied solenoid (which turns on at a higher set boost pressure and fuels the second and third injectors). After consulting the supplied directions and notes in the Snow Performance kit, Xtreme Unlimited in Oceano, California, chose to use only two injectors (only one with a larger nozzle after the solenoid instead of two). For maximum effects, you’ll want to use all three injectors (two after the solenoid).
But you can add a water/methanol mix to a diesel engine to cool the air/fuel mixture and clean up emissions while improving the efficiency of the burn and lowering EGTs. It’s a method that has been used for decades—as far back as fighter planes of the 1940s—and it can benefit your diesel truck, regardless if you have any power/cooling issues or not.
After adding a MPG-MAX water/methanol injection kit to our Florida-based 2011 6.7L Power Stroke Super Duty, we had a few questions on why water/methanol injections seem to work so well. Matt Snow of Snow Performance was the expert with the answers. Check out our insightful Q&A below.
OFF-ROAD: Doesn’t it take more energy to make more power? How can a water/methanol mix make more power? It’s still a fuel, so technically it’s an additional fuel used to make more energy, right?
Matt Snow: Energy is stored in many ways. One way is chemically as a hydrocarbon that is released when it is combusted. Another way is chemically when water changes state from a liquid to a gas creating the “steam effect,” which pushes down on the piston making torque.
More power is attained from methanol due to two factors:
1. The first factor is combustion conditioning. There is evidence in the research journals indicating that during combustion, when methanol (and to a lesser extent water) changes state, each droplet breaks-up creating many “micro-explosions.” These micro-explosions help better atomize the fuel droplets, facilitating more and smaller droplets that are more “ready” to combust. This combustion conditioning results in more of the available diesel fuel in the combustion chamber being burned (less going out the exhaust port burning or unburned) resulting in more power and less emissions (especially particulate matter and NOx).
2. Methanol is a fuel source. Also, the fact that more power is generated on the power stroke (as piston is going down after TDC) resulting in more net positive torque means more power is generated with a given amount of fuel. This also makes it “safe power.”
Many wonder how water alone can increase power since it isn’t a fuel. Water increases power through two main mechanisms. First, it lowers charge air temps, which increases air charge density (more oxygen available for combustion). When water changes state from a liquid to a gas, it absorbs heat. How much heat depends on the total surface area of the droplets, which is why atomization is so important. With constant volume, the more finely atomized the droplets, the more total surface area. Secondly, expansion takes place as the droplets change state during combustion creating the “steam effect” which pushes down on the piston creating additional torque. Also, this is “safe power” in that this torque is predominantly created as the piston is going down during the power stroke after TDC.
OR: Does water-meth injection into a diesel engine cut emissions? Wasn’t this used as far back as the early 20th century?
Snow: Water/methanol injection has big advantages with emissions. Specifically, NOx is reduced up to 70 percent and particulate matter (PM) is reduced up to 50 percent. This is significant because these are the two emissions that the EPA is most concerned about.
In the late 1800s to early 1900s, Rudolf Diesel recognized the benefits of water injection in diesel combustion as a way to get more useable work out of the heat of combustion. Just as turbocharging is a way to scavenge normally wasted energy, water injection is used for the “steam effect” in combustion where additional torque is produced as the water droplets go from liquid to vapor.
- 04.5 The red high-pressure tubing meets a quick-connect fitting that threads into the sid
OR: Is it legal? If not, why not?
Snow: The key to California Air Resource Board (CARB) certification and getting an executive order number for a product is proving that it doesn’t make emissions worse. Since water and water/methanol injection in a diesel reduces emissions significantly, it is just a matter of proving it with a CARB-approved testing protocol at a CARB-approved lab. This unfortunately takes a fair amount of time and money. We are in the process of getting the necessary certifications to satisfy CARB (and thusly the EPA) with a water/methanol injection kit. In certain states, emissions testing is not yet done on diesels, so diesel owners in those areas do not need to worry about emissions exemptions.
After doing some towing with our MPG-MAX system engaged, we can definitely tell the power difference and we can see a definite EGT drop coming up steeper grades. We’ll need to do some more testing before we can give you accurate fuel economy changes with the Snow Performance kit (and maybe even find a dyno to see the rear-wheel power differences), so look for a future report in our Long-Term Updates column.
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