how does water/meth injection work?

sojirovskensi

As the title says, how does it work?
If I go with the GTM s/c stage 2, is it better off to have it or not?
Also, besides the kit, how many labor hours will be required to install the kit and custom dyno tune?

Jordo!

Cools the charge, increases effective octane, and reduces likelihood of detonation. It was developed for fighter planes in WWII.

However, displaces fuel (i.e., gasoline) and air, so takes some experimenting to find the mixture of fuel, water, air, and methanol that works best for your application.

I recommend a progressive controller that increases the volume sprayed as boost increases. Also desirable to have some sort of warning light in case of clogged lines or low reserve levels.

Port injection is probably best, ideally with an injector for each runner; next best would be plumbing each intake tube; worst is spraying directly into the turbine as it may strip off coatings on the blades or even cause pitting. This potential problem is somewhat mitigated by using a very fine spraying nozzle on the injectors, so that the mixture is well atomized.

Some folks are big fans of it, others see it as a band aid for failing to run the correct octane for your tune.

Other negatives include the fact that methanol is incredibly toxic, so unless you buy premixed solution, you will be spashing that stuff around and mixing with distilled water yourself (only use distilled!) in the garage... also, methanol is pretty expensive, though still quite a bit cheaper than running race fuel.

I have a fair bit of experience with it -- and have mixed feelings about it in retrospect.

It can enable you to make greater power, but if it fails -- unless you have some sort of safeguard in place to pull timing or at least warn you so you can throttle off, whatever timing or boost you are running will probably be too high if the mixture runs out and that can lead to breaking a piston...

Google water injection -- tons of info out there...

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Jordo!

Ha ha ha -- a lot of views but no additional questions or comments?

Okay, some more info for anyone who might be curious:

You can actually just run straight distilled water as an anti-detonanat (water has a theoretical octane of infinity as it cannot auto ignite -- or ignite at all) and works better than anything else in terms of latent heat absorption capability.

The addition of alcohol (methanol being one of the best, others like to use toulene, but isoprohyl, thouugh less ideal, would work too) prevents freezing (water alone will freeze if it gets cold enough) and adds some addtional octane as well as potentially provides more torque -- you have to burn a LOT of methanol for this benefit... stoich for meth is around 6.5:1, so you need to burn more than twice as much for each unit of air.

This is also why if you have the motor set up to run on straight methanol you can make quite a bit more torque and power -- expensive and needs alcohol friendly components... tho'. That's a whole different project...

Anyway, if you search on line you can find out tons of info on the latent heat absorption capabilites, stoicihometrics, and typical octane levels of all of these various fuels.

Labor depends on how complex their kit is, but basically it should include lines, nozzles/injectors, a tank that has to be mounted somwhere, a (hopefully progressive) controller, a pump (aquamist has really trick ones, but a standard pump works just fine!) and ideally a few warning lights. Probably another 4-6 hours to get it all installed and buttoned up?

As to tuning time -- if it's already on, then it will take about as long to tune with as without it.

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Mike@GTM

You got it Jordo.

Just a little thing I'd like to add about the latent heat absorption of water vs. methanol. While the water has a higher heat capacity than alcohol, at lower temperatures (like those post intercooler), the water won't evaporate as much as the methanol will. Remember that the heat of vaporization is significantly higher than the heat capacity alone. That's why alcohol feels so cold when it's placed on your skin. The liquid isn't cold, it's just drawing a lot of heat from your skin as it goes from a liquid to a gas (thanks to its low boiling point). That's one of the other reasons alcohol motors make so much power: the evaporative cooling from the alcohol drops IAT's well below ambient and you end up with a much cooler, denser air charge so you can add more fuel.

Now, in regards to running it with our Stage 2 Supercharger Kit, we'll be making a post later this week about a project we're doing with water/methanol injection and our Stage 2 Supercharger Kit. So stay tuned for that to get a better idea of what can be done.

-Mike

Ron

Awesome info Jordo! Thanks. I was thinking about getting a water/meth kit and running a J&S SafeGuard to monitor and adjust timing.

J&S Electronics • Tech Articles I'll create a separate thread to discuss that system.

Jordo!

Ah -- that's right! I hadn't thought of that effect... it's been a while since I've played around with this stuff

I think there's ways to set up Osirus to aggressively pull timing if it sees a knock event -- I can't recall the fine details because I don't think the knock sensor log can be accessed... it's done in a round about way... GTM Mike or another person with more hands on expereince with Osirus might be able to address that one.

Anyway -- yeah, the J&S safeguard is a really good idea, especially if you are pushing things well beyond the factory specs. Definitely less expensive than a rebuild

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