Tuning tips: Water injection

[obi_waynne]

In a forced induction engine (turbos, superchargers and twin chargers) and to some extent a NASP engine with a high compression ratio you have the ever present risk of detonation. This is where the fuel prematurely ignites typically causing major engine damage. When adding or increasing the amount of air going into the engine you [...]
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What do you think of this tip then, read the article and post your comments in here.

 

[obi_waynne]

There must be a down side to water injection.

 

[HDi fun]

There must be a down side to water injection.

Apart from the cost of installation I can't think of any.

 

[jarrus]

Well, I guess there is in a way but it's the same with everything when it comes to cars and tuning them. Get it wrong and you will be left with a big repair bill.

I will be running water injection on my 306.

 

[HDi fun]

Water injection is absolutely superb at cleaning combustion chambers and piston crowns.

 

[jarrus]

Well that's one of the reasons for doing it, it should cool the charge temps down but I am going to be using an intercooler from a Mitsubishi Evo 6 so as for it's affectiveness with that as well I'm not so sure, but certainly for cleaning though, and I will be using only water mainly but I do have so model engine fuel which is a NitroMethane/Methanol mix which should work quite well.

I asked the bloke I bought the kit off if it will be ok, and he said he had never tried it but in theory it should. He also said not to go over a 30% mix (30%nitro and 70% water)

 

[xacro]

wich is the max compression ratio with regular fuel and water injection?

 

[jarrus]

Hard to say really, every engine is different really, water injection will allow you to do a few things...
1) Run a higher compression ratio without the risk of detonation,
2) Advance your ignition timing without the risk of detonation,
3) Run more boost pressure without the risk of detonation (you will need extra fuel for the extra incoming air but this can also be supplied with the water injection kit by using methanol
4) Also you can run leaner mixtures and use lower octane fuel.
It also clean combustion chambers and intake manifolds also, and it also means you don't have to have a giant intercooler.

 

[xacro]

do you think that a 16v fuel injected and water-alcohol injected can handle a 14:1 compression ratio on regular fuel? Or more?

 

[jarrus]

As long as it isnt supercharged or turbocharged and the connecting rods can take the strain then it's do able, but I would advise using the highest octane pump petrol/gasoline avaliable just in case

 

[Massive]

water into engine imagine getting the water injectors set up wrong, the spray in too much water - dead engine?

i tink ill leave water injection alone

Problems.
Water can cause corrosion so it becomes essential to properly maintain your engine and the intake will ideally need to be periodically removed for inspection.

If the water reservoir dries up then you will risk engine damage unless the fuel and air mixture is reduced.

 

[xacro]

where I can find a water alcohol injection system which vary the amount of water injected into the cylinders as a function of the rpm and has a injector for each cylinder?

 

[jarrus]

RPM based controllers are more like ECU's

A lot of aftermarket engine management systems will do this, also most water injection companies offer 1 injector per cylinder. DevilsOwn is one of them.