Lets Talk Water Meth Injection

[DVS JEZ]

Wasnt me Rob if thats what ur thinking. I have never touched a V8. Well till this saturday

I hope as a reputable "tuner" he was mis-quoted.

Quenching the chamber is exactly that - rapidly reducing the temperature of the combustion chamber.

[rob82]

Wasnt me Rob if thats what ur thinking. I have never touched a V8. Well till this saturday

I don't know who he's referring to mate. What v8 are you playing with?

I've also priced up the kistler in cylinder pressure transducers and they are quiet expensive. The other thing is having a scope that can give you enough channels with a high enough sampling rate.

I have used some of their quartz load cells and found them quiet robust.

[GTSBoy]

Sounds bad for the metallurgy.

[discopotato03]

No I don't - get it . Yes when water does a phase change to steam it does at at huge expansion rate - at sea level atmospheric pressure or one bar absolute . Putting water on an a fire in an enclosed space is fun , really cooks you up in the nomex gear if you spray too much .

Anyway W or WMI injection done properly works well .

A .

[GTSBoy]

I hope as a reputable "tuner" he was mis-quoted.

Actually, having just done the search, it wasn't the guy I thought it was who posted the info on how much water you can use. It was someone even more respected on that forum (and deservedly so, given that he's not as big a prick as the Sydney tuner I thought I was quoting).

I quote his posting below:

If you could be bothered reading >50 year old research there's some good info on water and water meth injection to be had from NACA (predecessor to NASA, consider it the scientific group for aero engineering) docs about ww2 era military air craft.

Some methanol in the mixture will lead to more power. This is because of (mostly) latent heat of vapourisation cooling the charge whilst in the inlet tract and leading to a denser intake charge being ingested. It is then of course flammable so it can add to heat energy created during the burn (though most if from latent heat of vapourisation)

Water on the other hand, doesn't do 'much' in the intake tract per se. By the time it's actually in the cylinder, it takes a lot of heat energy to actually get water to hit 100C (at sea level atmospheric pressure, and of course as the piston rises intercylinder pressure increases, and so does the boiling point) and turn to steam. Perhaps the way to conceptualise it is that the methanol drops the intake temperature (which is why it produces more power even on an NA engine with no other changes other than those to give the right a/f ratio for methanol vs gasoline) whereas water reduces the amount the intake charge actually heats up during the compression stroke. It rips a shitload of heat away. Basically that means it reduces the amount of energy lost to compressing the charge when the piston is on the compression stroke (as well as keeping it cooler and preventing pre-ignition or detonation later on). So that's why, even on an engine that doesn't have a borderline too high compression ratio, you can occasionally see gains from small amounts of water injection.

Once the burn starts, and the piston is past TDC the water will turn to steam, and it's expansion rate is high enough to contribute meaningfully to the power stroke.

And that's the tip of the ice berg.

If you are wondering about quantity, they researched up to and in excess of 1:1 water to gasoline ratio (*by weight from memory, or either way at least 1:1 by volume) of straight water and still found power gains, (as well as engine preserving gains.

On large engines with hard, large diameter bores and 1940s ring technology, at above that there wasn't a huge gain, but they were experiencing increased oil contamination. It'd be fine for 'the mission' but would require oil change (and possibly separation, though i have no data on how or even if they were equipped to do that, but using a still it'd be possible).

What this means is that for most streeters - with more like 10-20% water (vs peak petrol needs) you'd not have to worry at all for a good 5000km, or so (which is about when I'd change oil anyway). If it was for tractor pulling, and a shitload of water, change the oil each day of competition, or each run if it was a high level competition engine. Incidentally high boost engines running straight methanol tend to have to do that anyway (it's easier to get the methanol back out of the oil than the water, due to boiling point) each day, or each couple of runs.

In terms of value for money - obviously straight water is the 'go' by a long shot, and some would argue that the only place for alcohol at all is to act as an antifreeze. In that role, methanol, ethanol or iso-propyl would do that job fairly well, so take your pick based on price. If it's an extra 25-50bhp you want from a combo of a little more boost and methanol, then a 1:1 ratio of water and methanol makes good sense.

It was actually somewhere else (some other thread) that the mention was made of being able to keep adding it until it stops the cylinder from firing, but I can't find it. There's far too many threads on Wi and WMI on PF extending back more than 10 years.

You could go look at the forums associated with Aquamist (http://www.waterinjection.info/) where there's a bunch of stuff hiding.

Edited May 8, 2012 by GTSBoy

[DVS JEZ]

I don't know who he's referring to mate. What v8 are you playing with?

I've also priced up the kistler in cylinder pressure transducers and they are quiet expensive. The other thing is having a scope that can give you enough channels with a high enough sampling rate.

I have used some of their quartz load cells and found them quiet robust.

Pm sent

[GTScotT]

Once the burn starts, and the piston is past TDC the water will turn to steam, and it's expansion rate is high enough to contribute meaningfully to the power stroke.

Thanks GTSBoy, thats some conclusive information right there.

Obviously we wouldnt define that as a change in dynamic compression but it obviously has a similar effect to an increase in dynamic compression. Pushing the piston down as it expands (like increased DCR would).

Hard to define, but this is what I was on about the first time I said it. Its interesting to read that it doesnt expand during compression stroke, as I thought it did.

This is a pretty valuable thread.

[PSI086]

I've just received my aquamist hfs-3 so it will be interesting to see what gains are to be made. Its certainly a good looking piece of gear

[SiR_RB]

how much did that kit set you back?

[SiR_RB]

how much did that set you back?

[Mitcho_7]

how much did that kit set you back?

I thought I read somewhere that they arent heaps expensive. Probably be more expensive to set up if you don't know how to do it yourself.

Someone in Canberra get one setup, I wanna see how it goes seeing as we don't really have e85 anywhere...

[TiTAN]

I thought I read somewhere that they arent heaps expensive. Probably be more expensive to set up if you don't know how to do it yourself.

Someone in Canberra get one setup, I wanna see how it goes seeing as we don't really have e85 anywhere...

two e85 stations, one north side, one south side.

[Mitcho_7]

two e85 stations, one north side, one south side.

Which suburb northside?

[TiTAN]

nicholls, the caltex just off the barton hwy

[Mitcho_7]

nicholls, the caltex just off the barton hwy

Conveniently that is a mere 5 minute drive from my house!!!

[STATUS]

bugger.... i bought the dyno files home but i dont have the viewer on this laptop.

Just pulled the soarer with WMI back off the dyno and at 25 psi it made 445rwkw with intake temps averaging 20-24 degrees... it will pull that power run after run after run. It has more in it but we started getting a bit of bleed on the fuel pressure. This car is setup for circuit so it needs to be safe under all conditions so we stopped at 25psi and 445rwkw.

On 98 it would pull one run @ 380rwkw on 20psi but high intake temps held it back from running more boost.. and subsequent pulls would drop power with each pull via the AIT compensation. On 20psi it will pull 390rwkw all day with loads more mid and a near perfect power curve.

Overall timing gain was comparable to e85.

[PSI086]

how much did that set you back?

Was something like AU$720 delivered off some duds in the UK. Took forever for it to be sent. I don't think it works out much dearer to buy the kit from Howerton Engineering in the states

[blk94r33]

Was something like AU$720 delivered off some duds in the UK. Took forever for it to be sent. I don't think it works out much dearer to buy the kit from Howerton Engineering in the states

Did you get that directly from aquamist?

[GTScotT]

STATUS brings the big guns

That's what weve been waiting to see, the WMI is the answer for people without E85 as an option.

Woo

[Dale FZ1]

Overall timing gain was comparable to e85.

Matter of interest, what timing would it take?