Water/meth injection: a theoretical and practical discussion

[Ryan S]

On my old rev5 I had a progressive aem kit.

Currently have a basic coolingmist kit supplied by TFS.

are you just using water in that Jim?? i'm thinking about a kit for the same purposes you use it, but i'd rather just use water alone if it's possible.

[jimGTS]

Just water.
I did try 50/50 water meth, but it's dangerous stuff, plus unless you buy in huge drums, can be expensive. Plus hassle with mixing, I screwed up a mix and couldn't remember what on earth the ratio I had in there. So I just use deionised water only now.
Purely for ease and less hassle.

To be fair I haven't given meth a chance really, but it's not as if I noticed any difference, so thought I'd take out a poisonous/dangerous equation.

[Ryan S]

All of what you said is the reason i'd like to run water only!! Interesting stuff mate, i may pick your brain about it at some point

[bobhatton]

All of what you said is the reason i'd like to run water only!! Interesting stuff mate, i may pick your brain about it at some point

Think hard about the right place to put the water injectors, you want to stop knock in all cylinders, not just the ones that get the most water.

[Danbob]

Hi Bob, I'm in the same position at the moment aswell, got the inlet mani on my bench so perfect opportunity to add WI in the runners, or install it post IC depending on the conclusion of this discussion.


If I was to fit it in the manifold, would I have to go for a much more expensive system incorporating solenoids etc. rather than check valves, to stop water being pulled in under vacuum?

[bobhatton]

Hi Bob, I'm in the same position at the moment aswell, got the inlet mani on my bench so perfect opportunity to add WI in the runners, or install it post IC depending on the conclusion of this discussion.


If I was to fit it in the manifold, would I have to go for a much more expensive system incorporating solenoids etc. rather than check valves, to stop water being pulled in under vacuum?

You will just need one solenoid on the main pump feed before you split into 4.

[Ryan S]

All of what you said is the reason i'd like to run water only!! Interesting stuff mate, i may pick your brain about it at some point

Think hard about the right place to put the water injectors, you want to stop knock in all cylinders, not just the ones that get the most water.

it wouldn't be a case of thinking hard Bob, I've literally no idea where they would go!! it would be a case of listening hard

[bobhatton]

All of what you said is the reason i'd like to run water only!! Interesting stuff mate, i may pick your brain about it at some point

Think hard about the right place to put the water injectors, you want to stop knock in all cylinders, not just the ones that get the most water.

it wouldn't be a case of thinking hard Bob, I've literally no idea where they would go!! it would be a case of listening hard

Because the inlet manifold is what is called a "DRY" manifold, it is not designed to have any fluid in it, the distribution to each cylinder will not be the best, so you could have the water stopping knock in 3 of the cylinders but one my just not be getting enough.
The only way to ensure all the cylinders get the same amount is to fit 4 injectors in the manifold runners.

[Danbob]

Think hard about the right place to put the water injectors, you want to stop knock in all cylinders, not just the ones that get the most water.

it wouldn't be a case of thinking hard Bob, I've literally no idea where they would go!! it would be a case of listening hard

Because the inlet manifold is what is called a "DRY" manifold, it is not designed to have any fluid in it, the distribution to each cylinder will not be the best, so you could have the water stopping knock in 3 of the cylinders but one my just not be getting enough.
The only way to ensure all the cylinders get the same amount is to fit 4 injectors in the manifold runners.

In your experience are the Rev 3 inlet runner walls thick enough to tap and fit the nozzles directly into? Or would bosses need to be welded in?

Also could you suggest the optimum location in the runners (I expect to be mapping on water only)

[bobhatton]

it wouldn't be a case of thinking hard Bob, I've literally no idea where they would go!! it would be a case of listening hard

Because the inlet manifold is what is called a "DRY" manifold, it is not designed to have any fluid in it, the distribution to each cylinder will not be the best, so you could have the water stopping knock in 3 of the cylinders but one my just not be getting enough.
The only way to ensure all the cylinders get the same amount is to fit 4 injectors in the manifold runners.

In your experience are the Rev 3 inlet runner walls thick enough to tap and fit the nozzles directly into? Or would bosses need to be welded in?

Also could you suggest the optimum location in the runners (I expect to be mapping on water only)

I have never found a manifold I could not get a nitrous injector in so I am sure you can just drill, tap, and screw in with a water one. Do you know what system you want to go for so I can see what the injectors are like?
The best place will be in the top on the manifold as that is a low flow part and will disturb the air flow less, but there is not much room there so may have to go under the manifold.

[Danbob]

OK, thanks for the tip, I'll have a look at the mani later today to see what's feasible.

Would you suggest mounting the nozzles in the top of the plenum pointing down the runners? - Or in the runners themselves near the top?


I have no system in mind yet, but as always cost will be kept to a reasonable minimum.
I've got a long time before the car will be ready, so planning to bide my time and wait for a good quality recirculating pump to come up for sale second hand, then build the rest of the system up from there.

[bobhatton]

OK, thanks for the tip, I'll have a look at the mani later today to see what's feasible.

Would you suggest mounting the nozzles in the top of the plenum pointing down the runners? - Or in the runners themselves near the top?


I have no system in mind yet, but as always cost will be kept to a reasonable minimum.
I've got a long time before the car will be ready, so planning to bide my time and wait for a good quality recirculating pump to come up for sale second hand, then build the rest of the system up from there.

In the runners only.

Here you are, everything you will need from one place.

http://www.coolingmist.com/pagedisplay. ... re_Key=all

[2mad]

Edit.. Changed my mind, the search for a sensor, unaffected by water continues.


I will probably get slated but this was my theory (got the idea from a flow sensor) if the temp sensor is heated to 300c water would just vaporise when it hits the sensor and not mess with the air temp readings.


Just a thought my hunt continues.

[2mad]

Lots of interesting info on this .. http://www.max-boost.co.uk/max-boost/intake/WI.htm

[Danbob]

You could try finding a gas permeable membrane which is liquid impermeable, and fit it across the throttle body then run an experiement with and without the WI switched on.

No idea if such a membrane is commercially available or not, just an idea

[2mad]

This bench test inspired me somewhat .. http://youtu.be/mRGuzq74pEg if you pause at 15sec's imagine the fan is pushing 80/100c air (with a pre w/m temp sensor fitted) the air then moves into the rectangle chamber and it's hit with water/meth. The air then travels 15" down the 2.5" diameter tube to danbobs membrane filtering the water with a drain in the tube to let the water escape. Air temp is now measured on the opposite side of the membrane .

Anyone up for some science



Kev.


Edit.. For anyone that watched the video if there was a was to calibrate the sensor to read temperature and not flow it would be perfect for testing this theory .

[Martin F]

Quick question while a few members are posting and know more than myself.
If I fit a st205 chargecooler to my car, looking at running around 1.6 bar on a td06, would it be better to move my water injection from the throttle body to the turbo side of the chargecooler ?
In theory it sounds like it would work better at cooling the temps before they get to the temp. sensor but is it going to be practical running water/meth through the chargecooler core, will my inlet temp reading come down ?
Is the water/meth still going to be off benefit by preventing knock etc. ?

[2mad]

Hi Martin, Dont spray before the chargecooler it will just condense in the chatgecooler iiirr. fit the jet in the chargecoolers outlet or in the throttle body inlet .. like this .. http://gt4oc.md2.co.uk/5.jpg

[Martin F]

Hi Martin, Dont spray before the chargecooler it will just condense in the chatgecooler iiirr. fit the jet in the chargecoolers outlet or in the throttle body inlet .. like this .. http://gt4oc.md2.co.uk/5.jpg

That is where it is now, thanks for the info

[2mad]

OK, thanks for the tip, I'll have a look at the mani later today to see what's feasible.

Would you suggest mounting the nozzles in the top of the plenum pointing down the runners? - Or in the runners themselves near the top?


I have no system in mind yet, but as always cost will be kept to a reasonable minimum.
I've got a long time before the car will be ready, so planning to bide my time and wait for a good quality recirculating pump to come up for sale second hand, then build the rest of the system up from there.

In the runners only.

Here you are, everything you will need from one place.

http://www.coolingmist.com/pagedisplay. ... re_Key=all

Bob this ones for you (I know i've been playing devils advocate) and am quite happy with tfs's theory .. But heres my question, spraying 12 to 15" before the throttle body (rev3) what sort of flow (w/m) per cylinder do you think im getting from each runner . Do you think its an equal flow of w/m


Do you know for a fact one of the four runners could have restricted flow compered to the others , because its a dry manifold

This question is more important to me than if w/m cools intake charge.


Kev.


Ps. w/m = water/meth