Water Methanol Injection

Water Methanol Injection

W.I (Water Injection) was largely developed for internal combustion engines in the harsh world of rallying on turbocharged engines, in rallying turbocharged engines are pushed to the limit and in cylinder charge temps and inlet temperatures are at an all time high which can lead to dangers such as hot spots, pre ignition, melting and more importantly Detonation!!
If detonation occurs within a petrol engine serious damage can occur such as damaged piston rings, broken spark plus ends and worse case a hole in the top of your piston!!
W.I was designed for the sole purpose of reducing the chance of detonation by dramatically dropping inlet temps and in cylinder temperatures to massively reduce risk of detonation, it also aids combustion by slowing the process down to make the burn more efficient.
W.I can be used on any engine but the method of injecting and use varies with engine type so i will go into that later.....

How does W.I work???

To inject water into the engine/inlet track or turbo a high pressure water pump is used, running between 100 and 200 psi depending on make and model. On basic kits the water pump is activated by a pressure switch so injection can be made to occur only when a desired boost level is achieved.
The pump forces water through a very small hole inside a water jet so the water can be finely atomised, these jets are different sizes to flow the required amount of water to suit your engine.
More advanced kits come with a mappable injector driver such as the ERL Aquamist MF2 so the water flow can be reduced and increased over different rev ranges and loads to achieve the best results.

When water mist is injected into the inlet track it absorbs huge amounts of heat as it starts to evaporate resulting in a big drop in temperatures. It also has the added effect of steam cleaning the engine as it goes through although this isnt the purpose of the kit.

Who uses W.I and why???

Tuners often use W.I to safely increase power levels on an engine were the engine would other wise start to detonate, tuners can use W.I to raise boost levels, advance ignition timing and run higher C/R's without the risk of DET aswell as help maintain or often improve power from the more oxygen dense air entering the cylinder.
W.I acts like a high octane fuel when injected into the cylinder due to the cooling effects which often means less fuel can be injected for a better more efficient combustion.

W.I is also often used as a fail-safe on engines that are highly tuned so the engines reliability and overall resistance to detonation can be improved aswell as helping maintain a cool oxygen rich flow of air into the engine which can improve power and torque considerably.

W.I and its effects on power and torque.....

An often debated subject!, but here goes....

by injected water into the inlet temps drops as we now know, and this leads to more dense inlet air which naturally is more rich in oxygen...more oxygen will create more power when mixed with more fuel to maintain a healthy air fuel ratio, this is where methanol comes into the mix.
Methanol acts as the extra fuel needed to richen up the mixture which can be leaned out from the effects of W.I, it acts as a coolant in the same way as petrol does so the heat absorbing properties of the system are little effected by the Methanol.
Because of this BHP and torque can be strongly maintained and more often than not increased!

here are some interesting facts and info of the net that will help explain why running W.I can increase your power output!!-

From the table below, you will note that air at 0C contains almost 30% more oxygen per given volume, than air at 77C.

Air Temperature
Air Density
% increase of oxygen

77C
0.9950 kg/m^3

40C
1.113 kg/m^3
+ 12% oxygen

27C
1.1614 kg/m^3
+ 17% oxygen

0C
1.2763 kg/m^3
+ 28% oxygen

So if your car is tuned for say 12.0:1 fuel mixture (rich) for maximum power and the air going into your engine is at 77C, you might make say 241bhp @ wheels. Now if you could get that intake air down to 0C and still have your engine tuned at 12.0:1 fuel mixture, you will make 30% more power based simply on oxygen levels in the air = 241bhp @ wheels x 1.3 = 314bhp @ wheels. That’s a massive 73bhp increase!!! Now obviously, unless your using dry ice somewhere along your intake path, you won’t get the air to 0C, but that is just to give you an indication of the true effects of air temps and their relation to power output.


Its also worth mentioning that water absorbs 6 times more heat than fuel which accounts for upto 70% of cylinder cooling.

where does the water nozzle/jet go???

this depends largely on how you want the kit to function, the most common and most recommended place for the jet for a balance of inlet air temp drops and in cylinder cooling is to fit the jet just after the intercooler so the water can properly mix with the charge air and partly evaporate before it enters the engine, this ensures the air entering the engine is cool and the water can also enter the cylinder to continue to cool and make combustion more efficient.

The second place to fit the jet is within 10" of the TB, this allows the majority of the water methanol mist to entire the engine to optimise the anti detonation properties of the kit while allowing the inlet manifold to distribute the water methanol to each cylinder.

Along the same lines as above another tuner favourite is to inject the water just before the IAT sensor close to the TB, this makes the ECU see a much cooler intake temp so the ECU injects more fuel to richen the mixture, this can help increase the BHP from the system aswell as balance out the air fuel ratio.

Pre intercooler jetting.....

this is something that isnt advisable for road cars, recommended for high revving race cars it can massively increase the efficiency of the intercooler but there is a risk of water collecting in the bottom of the intercooler on road cars!!

Pre turbo jetting.........

Widely discussed!!!, this is an area that should be treated with care!, water injected here should be minimal using a small very high pressure jet to ensure a finely atomised mist of water enters the turbo so the mist can be quickly evaporated by the hot compressor wheel.
Failure to get this set up right can lead to a damaged or worn compressor wheel!!, but set up correctly the effects of W.I here can be pronominal

Injecting water into the turbo's compressor chemically changes the compressor map so the turbo can be made to work far more efficient at higher boost levels and by optimising the boost in this way power gains can be higher and inlet temps massively reduced before the air gets anywhere near the engine.
ERL recommend injecting the water close to the compressor.

MPI W.I.....

This is the most technical of the set ups and needs to be carefully calculated, injecting water into the inlet port of each cylinder is by far the most effective way of lowering the charge temp within the cylinder right through the combustion process. By injecting the water here its often necessary to remove some of the fuel because the water replaces it in the way of cooling, allowing the process to be far cleaner and more efficient while helping to improve peak cylinder pressure and volumetric efficiency.

Jet size???

jets sizes are very important indeed, an incorrectly sized water jet can decrease an engine power, cause water to collect in the inlet and generally cause problems!, the factors that decide which jet you need are the maximum engine RPM, the boost pressure you will be running and the size of the engine. This info will anable your tuner or seller to equip your kit with the right size jet.



TO BE CONTINUED LATER AFTER SOME SLEEP

thanks

Jason