Is Water/methanol Spray Better Than Fmic?

[kastin]

how much is methanol? where do u get it from? mixture is 50/50?

and how quickly would u go through a 10l tank?

[StockyMcStock]

cheers mike, sounds like it will be okay. although in a race car, you probably use the mix up at quite a prodigious rate, and that rate would not drop to zero for long periods.

in my street car, i would set it up so that it started going around 7psi and increased up to full boost. now i probably only spend about 1% of total driving time above 7psi, so the pump would not be working for long periods.

my concern is then that there could be large air pockets in the line, which would delay the speed of actuation when next i boosted.

i guess the answer is to run a check valve right at the nozzle, and a check valve right after the pump.

[r33_racer]

Yeh dale ours is water/meth. My understanding was the water helps stabilise the fuel from preignition and the methanol helps remove alot of the heat out of the air charge as it evaporates whilst moving towards the inlet valves. So by the time it does reach the combustion chamber, its more water with a lil meth then the perfect 50/50 brew thats initially sprayed into the i/c pipe.

And neill the kit we got from Full Throttle in Sydney i think have one way valves and solenoid kits for wastegate bypass and all sorts of little safety devices which you can incorporate into the kit to make it as safe as possible. The whole idea of water/meth injection as Rev210 said is as old as the hills...from around ww2 i believe, but making a reliable electronic kit with devices built in it that wont let it cause any engine damage if it does fail is whats so good about it these day.

[Dale FZ1]

Yeh dale ours is water/meth. My understanding was the water helps stabilise the fuel from preignition and the methanol helps remove alot of the heat out of the air charge as it evaporates whilst moving towards the inlet valves. So by the time it does reach the combustion chamber, its more water with a lil meth then the perfect 50/50 brew thats initially sprayed into the i/c pipe.

The whole idea of water/meth injection as Rev210 said is as old as the hills...from around ww2 i believe.

The benefits from using the water/alcohol mixture vs 100% water to me are questionable when/if you weigh up the logistics of buying, storing and mixing the brew at consistently the same blend. Personally I'd steer towards 100% water - 20 litres of distilled water isn't costly, difficult to obtain, or offer any difficulties in storage. Having said that, I'm not to argue whether there is a performance advantage one way or the other. Whatever the case, or the % blend, you can be assured though that if you inject a 50:50 mix then it will still enter the combustion chamber in the same proportions.

The principle of heat transfer to the atomised spray works the same regardless of whether it's pure water or a mix, so all that happens is you have water and alcohol drawn/forced into the combustion chamber that has been converted to gaseous form. It's the conversion that drops the charge temp.

The chemists amongst us can inform which of the two has the greatest latent heat value, but there is obviously a limit to the amount of water or water/meth that is optimal for a given engine. And depending on the mix, that may vary. All pretty straightforward application of science that I recall from senior school days.

My general understanding is that these vapours do indeed affect the rate of flame front propagation, slowing it down in similar fashion to using high octance racing fuels. So you've got the double whammy of cooler charge and extra knock resistance which allows more advance.

Yep, water injection was used/developed in WW2 piston engine driven planes as was various types of forced aspiration to help them get off the ground quickly, and operate at high altitude (in particular). There were a few cluey blokes around well before we came into being.

Edited March 5, 2007 by Dale FZ1

[S3_Girl]

So would I be right in assuming that you need some available headroom in your turbo? I mean that my turbo is already maxed out so will my only gains be made with timing?

Totally the oposite, you car is crying out for pre-turbo water injection, add a CDI ignition, inject

15 percent water of total fuel used and watch that compressor come back to life and it shoots back from the right hand side of the compressor map back to the middle! The ULTIMATE way to build a stomping street car with mass

of bottom end with strong as top end

Water- holds of detonation and lower combustion pressures the most- engine lasts the longest.

water/methanol- makes more power, but is easier to detonate.

Methanol- has to have so much injected its not funny, look at american supras, does nothing to hold

of detonation from lower combustion , all the powers made from more octane.

Boost referncing is not going to stop the compressor wearing out, using the correct atomiser will

you can get water atomisers- they wear compressors, or water/air atomisers, they shoudn't.

cheers

darren

Edited March 6, 2007 by S3_Girl

[Cubes]

Ahhh so thats the secret Darren.

You don't run water inj on yours do you?

[S3_Girl]

No, its shit, it just makes 850hpGt42 turbos flow more than 1000hp

and keeps stock bottom end motors in one peice.

cheers

darren

Edited March 6, 2007 by S3_Girl

[S3_Girl]

http://www.ausrotary.com/viewtopic.php?t=3...water+injection

http://www.aquamist.co.uk/phpBB2/index.php

[Chris_R33GTSt]

This is a really dumb question, but doesn't water make metal rust?

[BAMR33]

Another idea probably won't work but anyway... use the boost function in the powerfc to control what volume of water is being injected at a specified rpm by adjusting solenoid duration.

[Dale FZ1]

http://www.ausrotary.com/viewtopic.php?t=3...water+injection

One of the best technical threads I've seen. Top marks for finding it, and thank you for sharing.

I noted the opinion that while there are undoubted benefits from using WI, there is a point below which the expense makes it not worthwhile - provided all the conventional bolt ons and tuning is already in place.

What I really enjoyed was the attempt to enlighten us on how water is actually involved in the chemical processes of combustion, rather than being present but uninvolved.

cheers

[jeza]

www.coolmist.com i got one on my R34 it is good

and the tell you to fit after the cooler not b4 it

lef the cooler do its job and then the water injection

cool it ferther. cost me about $380 ozzy.

also cgeck out ebay type in water injection

good luck

[jeza]

p.s

also wen u order it they will ask u about the powe u have,

so they can give u the right injectro

i also use 30%meth 70%water good mix

[SKiT_R31]

How much of the water/methanol mix will the car use in relation to petrol? say a worst case scenario (constant full throttle) would it use about ~ 10% the amount of fuel being used? (so on a car doing 20L per hundred, about 2L use would be about right?)

Also, ive heard of mixes like 20% mentholated spirits and 80% water, ive heard normal metho safe to use???, and what differs between the mixtures [i.e. more or less metho/methonol]?

as for the rust comment, ive actually heard it does more in terms of actually cleaning your engine and piping, from the pressurized mist (steam clean )

[r33_racer]

haha whats it going to rust...head is alloy, pistons are alloy, and the heat will burn any rust off anything anyway.

[ProphetR33]

haha whats it going to rust...head is alloy, pistons are alloy, and the heat will burn any rust off anything anyway.

The intake plenum would be the only place that there would be an offchance of residual water.

In any case, I agree it won't rust. Rust forms when iron is exposed to impurities in water that trigger the oxidisation process, given the heat of the intake, high pressured airflow and the density of the mist there is pretty much no chance that there would be any water left to trigger the oxidisation in the first place. No more than a humid day would leave, or condensation when left over night etc etc.