Okay, here I have a tank,
a reservoir which I'm going to fill with water. This pump is then going to take the water from the tank, pressurize it and send it to this little nozzle which is going to inject the water into the engine. Okay, so that's the plan. Now, let's
install all of this onto the car
*installation sounds
Okay so here's the setup installed. Here's the tank with the water, there's a line going from the tank to the pump and then another
line continues and goes into the engine bay right here, it enters and
then it gets injected right here. There's a nozzle there, underneath this cable for the
throttle body. It injects water here before the throttle body and the intake manifold and
how much water and when is it being injected it's controlled by this controller
the electronics right here. And inside the car I have this little display which also tells me
what's going on, how much water, when. And this little light which glows red when
the tank is completely empty. So now, let's fill up the tank, fire the
car up and take it for a spin
*car spin sounds That's crazy! I need to take this to a dyno! So we measured 273 horsepower and 373
Newton Meters of torque. But this is at 5,500 RPM and this engine is
capable of revving to 7,000 RPM but we couldn't get to 7,000 RPM
because the boost pressure kept popping off couplings and
destroying hoses and whatnot and eventually we ran out of time and had
to call it a day, so the engine is capable of making more power if we can get to the redline
in the future. In case you're wondering this engine is a 1.6 L Toyota 4AFE engine.
An economy Toyota engine from the '90s taken from a Carina E, turbocharged and transplanted into
my MR2 mk1. The previous setup, without water injection was 198 horsepower at 6,700 RPM
so definitely a big big increase right here. Okay, hold up. What just happened? How does injecting
water into an engine make more power? Because water is an incompressible,
incombustible liquid it doesn't really belong inside an
engine does it? Well, of course, the water is not what's making the power
What the water is doing is enabling the engine to run a much more aggressive tune and
that's what's making the power, and that works because we are making the
engine sweat on the inside I know it sounds like nonsense but to
understand water injection in engines you have to understand when do you sweat? You sweat when you are hot. Water forms on the surface of your skin and as that water evaporates you cool
down. That works because water has a very very high heat of vaporization. In
more simple terms, as water transitions from a liquid to a vapor it
takes away massive amounts of energy in the form of heat from its surroundings. So water forms,
it evaporates, it takes away excess body heat. This is also why you're cold when somebody
pours a bucket of water when you're outside. Water evaporates, takes away
too much body heat, your body struggles to maintain a normal temperature and
you start shivering. We're doing the same thing inside an engine. We are
injecting fine droplets of water and as they transition from a liquid to
a vapor they take away massive amounts of heat from inside the engine. And that's good because
excess heat is the ultimate killer of power and efficiency inside an engine. Most gasoline engines, especially those with a turbo or a supercharger are limited by knock and/or pre-ignition Knock and pre-ignition are NOT the
same thing. Pre-ignition occurs before the spark plug fires, when the piston
is still going up. Pre-ignition usually destroys an engine pretty quickly and it can easily burn
a hole through a piston. Knock, on the other hand, occurs after the spark plug
fires, when the piston is going down. Knock can be anything from very
mild with minimal damage to very destructive Excess heat inside the engine
is the main prerequisite for both pre-ignition and knock and inside the
engine we manage the following three things to avoid pre-ignition and knock and they are:
1. Intake air temperature. 2. air fuel ratios and 3. ignition timing. As the name
implies intake air temperatures refer to the temperature of the air inside the
intake manifold. This is the temperature of the air right before it goes into your combustion
chamber. The higher the temperature of this air the greater the chance of
knock and pre-ignition. This is why almost all turbocharged vehicles
have intercoolers. Before going to the engine the air gets passed through the intercooler, which
has thousands of little fins for a maximized surface area so that it can pass as much heat
from the intake air onto the surrounding ambient air outside the engine. The intercooler cools down
the air leading to greatly reduced intake air temperatures which helps
prevent knock. But for an intercooler to work we need good flow of outside air
over the intercooler, and as you can see in my case we don't have that. The intercooler
is in the back and it's in a horizontal position so it's definitely
not exposed to good air flow which leads to high intake air temperatures in all but the
coldest of weather. Starting with 19° ambient air temperature here's what
my intake air temperature looks like after 22 km of spirited driving on an
open road. As you can see that's 40° C above ambient But things would get even worse in summer
when I first tuned this car it was summer and ambient temperatures were around 36° C, and what
happened once was that after driving hard I had to come to a stop due to some road works, I had to
wait for a few minutes and during those minutes I watched my intake air temperatures
reach a bit over 80° C. As I took off my ECU registered a knock
spike. Of course I panicked as seeing knock on a brand new engine
is never good, so I proceeded to immediately remedy the problem and I did it by
modifying my air fuel ratios. Of course air fuel ratio refers to the ratio of air to fuel going
inside the combustion chamber. Usually the best power at high RPM and wide open
throttle is made when we have an air fuel ratio of around 12.5:1 - That's 12.5 units of air to 1 unit of gasoline To play it safe I
was running 12:1 back when I first tuned the car. When I experienced knock
what I did is that I immediately changed all my air fuel ratios in boost from 12:1 to 11:1.
This is a richer air fuel ratio. In other words we have more fuel inside a combustion chamber,
this increased quantity of excess fuel cools down the chamber as it vaporizes
just like sweat as I explained at the beginning of the video. But
11:1 is not the ideal air fuel ratio for power so my power dropped off
and my fuel economy was also negatively impacted, but knock never
happened again. But gasoline sucks at taking away heat compared to
water. That's because the heat of vaporization of gasoline is around
400 KJ per kilogram. So it takes 400 KJ of energy to vaporize just 1 kilogram of gasoline.
The heat of vaporization of water is 2,260 KJ per kilogram. So water is
dramatically better at taking away heat from its surroundings. So what I
did after I installed my water injection system is that I changed my air fuel ratio under boost
to those for best power which is 12.5:1 and I never had to worry about pre-ignition or
knock ever again in any weather because water is great at taking away heat from its surroundings.
Although the primary benefit of water injection is to cool the chamber it also helps to cool intake
air temperatures because the water is injected here before the throttle body, before the intake
manifold, so already it starts vaporizing a bit there and takes away some heat from the
intake air. And here you can see my intake air temperature after
that same 22 km spirited drive on the same road, same day, same
ambient temperature. I reduced intake air temperatures by 5° C. Not much
but it definitely helps. But more importantly, I have to come clean. I wasn't able to achieve my
final power figure with water injection alone and just leaning out the air
fuel mixture. This gave me only around 16 horsepower.
My final power figure was achieved when I mixed water with alcohol. Now
alcohol or ethanol is great because unlike water it is a compressible and combustible liquid, just
like gasoline. But it's better than gasoline. If we put ethanol and gasoline side by side
we can observe the benefits of ethanol As you can see gasoline has a
higher net energy content but ethanol has a much richer air
fuel ratio for best power But this is not the primary
benefit of ethanol The primary benefits are that it has a higher heat
of vaporization, so it cools the chamber better than gasoline And it has a higher Octane rating compared to gasoline. The Octane number refers to a fuel's resistance to knock. The higher
the octane number - the greater the resistance to knock or spontaneous self ignition of the fuel.
So what's the ideal ratio of ethanol to water? Well the common practice is to mix 50% water and
50% ethanol and inject it into the engine
Now something that's very important to understand
here is that if you took this glass of water and this glass of ethanol, mixed
them together and injected them into your engine, this would not be
50% water and 50% ethanol, even though the volumes are equal. Allow me
to demonstrate why. Here's the water and here's the
ethanol and as you can see the water weighs a bit more than the ethanol. This is because water
is a bit more dense than ethanol and this is why we do not measure volumes of the things we put into engines such as air, gasoline, other fuels and in this case water and ethanol And that's because volume and density change with temperature So if we measured volumes like this, then we would not have an accurate measurement of what's actually going into the engine because the density changes as temperature changes This is why we measure mass. The stoichiometric air fuel ratio of gasoline Which is 14.7:1 is 14.7 units of mass of air to 1 unit of mass of fuel So if you want to put an actual 50% water and 50% ethanol mixture into the engine You need to put and measure a slightly greater volume of ethanol to get an actual 50/50 mixture So with ethanol and water in the mix I not only reduced the heat in the chamber but I also increased my resistance to knock and this allowed me to do two things 1. Increase my boost pressure and 2. Increase my ignition advance. Increasing boost pressure of course increases power but it also introduces additional heat into the system leading to increased risk of knock. But I can re-introduce heat into the system because I have taken away a lot of heat with water-ethanol injection. Increasing ignition advance can also increase power but it too increases pressure and heat in the chamber and leads to an increased risk of knock. It is here that the increased knock resistance of ethanol helps the most. Here we can see the difference between 10 and 20 degrees of ignition advance. As you can see by the time that combustion reaches peak pressure the piston is further down the bore the later we fire the plug It is obvious how 20 degrees advance can make more power The piston is much closer to the combustion which means that more of its energy gets transferred onto the piston. But 20 degrees is also more dangerous because the combustion is building peak pressure in a much smaller space. And that means more heat and more pressure Even if we manage to cool down the chamber, the heat and pressure spike during this time is so high that knock can occur even with water injection So what we ultimately ended up doing on the dyno is to first increase ignition advance in this are right here, which was our expected peak power area with my starting boost pressure, which is was 1 bar or 14.5 psi before I installed water - ethanol injection We got a little increase with our ignition advance and then we decided to start increasing the boost pressure to see where knock would occur with the water-ethanol injection. We first went from 1 to 1.3 bar Then we went to 1.5 bar, there were no signs of knock. So then we decided to just go crazy and try 2 bar which is the maximum boost pressure I can produce with my current wastegate and boost controller combination And even with 2 bar there were no signs of knock We could never get to the redline because the boost pressure was too much It kept knocking off, popping off couplings and destroying hoses and we eventually ran out of time trying to fix all that and called it a day. But even with that much boost pressure, so double my original boost pressure, there was no knock. We even had consistently high intake air temperatures of around 50 degrees Celsius, but still no knock What I should add is that I could have perhaps achieved an even higher power output by running methanol instead of ethanol because methanol has an even richer air-fuel ratio for peak power and an even higher heat of vaporization but methanol is toxic and cannot be legally purchased by individuals in most countries in Europe so I went with ethanol which is very close in performance and isn’t toxic But wait, there's more! Because with water-ethanol injection I never have to worry about carbon deposits in my engine ever again. Because the water-alcohol solution acts almost like a steam cleaner inside the engine. And it keeps the insides permanently carbon deposit-free. So with all these benefits we have to ask ourselves why don't cars come with water/ methanol/ ethanol injection from the factory if it's so good? Well, cars don't come with this...yet I think that pretty much every turbocharged car nowadays would benefit from a only water or water-ethanol or water-methanol injection system Because nowadays we have engines which are 1 to maybe 1.6 liters and we're making 120 to 300 horsepower from engines which are so small Of course making such big power from such a small displacement means that we need a lot of boost pressure And a lot of boost pressure means that we're making a lot of heat So if you take such an engine, take a hot summer day, put it in stop and go traffic Things get very hot very quickly. And being a factory engine it has nothing other than gasoline to work with So when it senses that tiny little bit of knock it's going to inject a lot of extra fuel and keep injecting it to stop and/or prevent knock in these conditions And if you owned or own such an engine I'm sure that you have noticed that in such conditions, a lot of heat, stop and go traffic, these engines are fully incapable of getting anywhere near their advertised fuel economy With water injection we could cool things down and restore power and restore fuel economy to such engines Now this isn't happening yet but it has been experimented with in the past There was a very famous instance, it's the Oldsmobile Jetfire In the States, back in the 60s, it had water-methanol injection from the factory and Americans being Americans they called it "Rocket Fuel" The problem was that "Rocket Fuel" was very expensive so owners didn't really keep the tank topped up so the car wasn't really a success. But now when we have ever more stringent emissions, fuel economy standards, water injection is again being experimented with. and the latest attempt is from Bosch and BMW which have co-developed a system that, which is very important, does not need topping up You don't have to worry about it. It does its thing by scavenging water from the operation of the air conditioning system. So, not topping up Whether it happens in the future, whether it becomes mainstream, we will see but the benefits are undeniable, and as we go even further into ever smaller ever more powerful engines I think water injection systems might become more prevalent in the industry So if I had to sum it up in one sentence I would have to say Many problems, but one pretty effective solution So that's pretty much it, as always thanks a lot for watching and I'll be seeing you soon with more fun and useful stuff on the D4A channel *music
