Water/meth injection: a theoretical and practical discussion

[2mad]

http://en.wikipedia.org/wiki/GM-1

"A different system for low-altitude boost known as MW 50 was also used, although GM-1 and MW 50 were rarely used on the same engine. MW-50 was a methanol-water injection system, which injected a mixture of methanol and water into the cylinders to cool the mix. Cooling causes the air to become denser, therefore allowing more into each cylinder for a given volume. This is the same principle that intercoolers use."

[raptor95GTS]

indeed, but the method used by the Allies of injecting into the supercharger intake did cool the inlet temperature er like an intercooler hehe. I think for us, anywhere we can get it to fit within our own budgets will do just nicely

[bobhatton]

if you're going to use water injection, you might as well do it properly and fit a progressive kit so you maintain the ratio of WI to fuel throughout the rev range of use. No point dumping the same amount of water / meth at 10psi as you do at 15psi boost, you'd either run too much at 10psi boost to get it right for the 15psi boost requirements.

Bob will argue where that kit should actually be fitted but I don't think he'd argue against a progressive kit. Then again he might, just for the crack of it

I was building progressive H2O injection systems in the 1970s, in fact still got a number of the controllers in stock.

[T.F.S.]

I have put many data logs with the mixtures used on my WI thread on this site, its very well documented and contains a lot of information....no intercooler, no chargecooler, 95 octane fuel, 22psi, garrett ball bearing turbo, stock head gasket/pistons etc, temps on boost have been below freezing on a 26 degree ambient measured with AEM sensor on link G4.

Water does not cool intake temps, yea right Bob.

For more info please read.
http://www.aquamist.co.uk/vbulletin/arc ... t-286.html

[Danbob]

I have put many data logs with the mixtures used on my WI thread on this site, its very well documented and contains a lot of information....no intercooler, no chargecooler, 95 octane fuel, 22psi, garrett ball bearing turbo, stock head gasket/pistons etc, temps on boost have been below freezing on a 26 degree ambient measured with AEM sensor on link G4.

Water does not cool intake temps, yea right Bob.

For more info please read.
http://www.aquamist.co.uk/vbulletin/arc ... t-286.html

Hi, could you link to your thread on this site, I'd be interested to have a read, cheers

[T.F.S.]

http://www.imoc.co.uk/forums/viewtopic. ... &start=140

[bobhatton]

I have put many data logs with the mixtures used on my WI thread on this site, its very well documented and contains a lot of information....no intercooler, no chargecooler, 95 octane fuel, 22psi, garrett ball bearing turbo, stock head gasket/pistons etc, temps on boost have been below freezing on a 26 degree ambient measured with AEM sensor on link G4.

Water does not cool intake temps, yea right Bob.

For more info please read.
http://www.aquamist.co.uk/vbulletin/arc ... t-286.html

Anyone that has done a scientific study of water injection in a climate control dyno room will tell you that a temperature sensor in the inlet manifold that gets any injected liquid on it can NEVER read the correct air temperature.

[T.F.S.]

Can you supply a link to "a scientific study of water injection in a climate control dyno room"?

There are plenty of people that spray water before the turbo, you cant tell me that any of the small amount of water they use remains as liquid after going through that so I cant see why the manifold would not be a suitable position for temp reading.

[dazzz]

Can you supply a link to "a scientific study of water injection in a climate control dyno room"?

There are plenty of people that spray water before the turbo, you cant tell me that any of the small amount of water they use remains as liquid after going through that so I cant see why the manifold would not be a suitable position for temp reading.

It's an interesting subject.

TFS, if you don't mind me asking, what are your credentials so to speak. im not being rude, do you have relevant a degree, experience, I don't know your background. I know Bob was building turbos n xxxx back in the 70s for f1. I bet he's got some stories to tell.

How can you be sure you're not getting a false reading of the intake air temps. Any water vapour collected on a thermocouple and then evaporating off of it would give a false reading. It would be a lot lower.

On your setup, you've got hot, pressurised air at an unknown temp. Your injecting water and the air temperature entering the chambers is below freezing?? To me this sounds to good to be true.

Im not saying anyone is wrong, we're just discussing the theory.

[JD]

Is TFS is the same TFS that sells water/meth injection kits on eBay (from which I bought mine, ta). Confirm/deny?

[T.F.S.]

Yes Bob seems to have a lot of story's, pity he does not have any hard evidence/testing data to prove anything which is odd for someone who has spent so much time testing something as simple as a water injection system for seemingly years on end..

I have an analytical background/job, I design drug formulation coatings and conduct many tests on these compounds on a daily basis so I am no stranger to testing in an analytical fashion.



I started work when I was 16 with a race team, I have been a nitrous/WI installer for something like 15 years.

The very low inlet temp figure was with methanol and water, it's not that surprising really.

[dazzz]

I would imagine so

[dazzz]

Yes Bob seems to have a lot of story's, pity he does not have any hard evidence/testing data to prove anything which is odd for someone who has spent so much time testing something as simple as a water injection system for seemingly years on end..

I have an analytical background/job, I design drug formulation coatings and conduct many tests on these compounds on a daily basis so I am no stranger to testing in an analytical fashion.

Image Replaced With URL For Quote [url]http://i42.photobucket.com/albums/e327/TEFUS/20120306_141155_-_TonyMatarPerga.jpg[/URL]

I started work when I was 16 with a race team, I have been a nitrous/WI installer for something like 15 years.

The very low inlet temp figure was with methanol and water, it's not that surprising really.

So how can you be sure your reading o f the inlet temps is correct? Do you see my opinion with regards to the moisture collecting on the probe.

I'm no expert when it comes to car engines and injection systems but I am an expert in testing and measurements.

[dazzz]

What sort of pressure and temperature is the water and methanol before its injected.

To drop air temps over the range I'm guessing that fast it would require a lot of energy?

I'm very interested in the theory. I don't disagree with the benefits of WI but would like to know the math behind it.

[Danbob]

For more info please read.
http://www.aquamist.co.uk/vbulletin/arc ... t-286.html

This is a very interesting topic, hope we get to a definitive proven answer,
I was going to calculate the possible cooling effect of WI Thermodynamically, but the guy in the link above has done it for me.

What I can't see in his calculation is where the amount of time the water spends in suspension in the airflow before it reaches the intake is taken into account?

I think this was Bob's argument for its ineffectiveness, that there is not enough time for the heat to transfer from the air to the water.

Or am I missing something?

[dazzz]

For more info please read.
http://www.aquamist.co.uk/vbulletin/arc ... t-286.html

This is a very interesting topic, hope we get to a definitive proven answer,
I was going to calculate the possible cooling effect of WI Thermodynamically, but the guy in the link above has done it for me.

What I can't see in his calculation is where the amount of time the water spends in suspension in the airflow before it reaches the intake is taken into account?

I think this was Bob's argument for its ineffectiveness, that there is not enough time for the heat to transfer from the air to the water.

Or am I missing something?

In the link provided....

I don't like they way he assumes T3, I don't think this is correct. An air temp of 125 would not reduce to 75 with the addition of coolant at 25. If it could reduce the temp to around 100 within the time frame required I would be surprised.

Try changing T3 to a figure more like 110 for giggles.

I'm no expert in this stuff, I just like things to make sense

[T.F.S.]

So how can you be sure your reading o f the inlet temps is correct? Do you see my opinion with regards to the moisture collecting on the probe.

I'm no expert when it comes to car engines and injection systems but I am an expert in testing and measurements.

I don't have any evidence that it is 100% correct but I seem to be the only person in the discussion bringing any evidence at all, what we do know is that methanol engines run very cold in general and the freezing temps I recorded were when injecting around 2L per min of methanol (still with 250cc of H20 mixed in) which does not really surprise me.

I cant see what water would remain as liquid after passing through the turbo (pre compressor inj) so this argument would seem irrelevant in that scenario, phase change happens before the liquid even reaches the turbo, even if it wasn't there would be explosive vaporisation at the tips of the compressor, temperature of the inlet is reduced due to latent heat of vaporization.

[T.F.S.]

What sort of pressure and temperature is the water and methanol before its injected.

To drop air temps over the range I'm guessing that fast it would require a lot of energy?

I'm very interested in the theory. I don't disagree with the benefits of WI but would like to know the math behind it.

In my case it was around 200psi with ambient temps that are recorded in the logs.

[2mad]

Brian hows things, are you still running intercooler-less. Any new w/i projects in the pipeline


Whats your current setup like has it changed much ?



Kev.

[T.F.S.]

Hi buddy, the MR2 was sold in parts a while back, girlfriend wanted something newer and after 10 years of owning the car I couldn't really refuse ;(

I don't have a current project car, been busy moving house and stuff.