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Water Methanol Injection Ratio mix and AEM controller

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Hello, I have 2 (dumb) questions concerning WMI tuning.

Does the full psi knob on aem V2 controller set 100% of flow that the nozzle can provide or at contrary it set the maximum flow of a nozzle? E.G et 20 psi with knob set a 20 psi 100% of duty of pump or something like 70% to limit the flow?

Is there a limite of WMI injection? I mean I think at a moment we inject too much water? I think that methanol isn't the matter as it's a fuel and as long as lambda is ok no worry, but is there a water to air ratio or a water to fuel ratio to respect? How much is too much?

Best Regards Guillaume

I haven't used that specific controller but usually the controller would provide maximum flow at the full psi setting and from here the flow is dictated by the nozzle size. AEM provide some suggestions on WMI flow to get you in the ball park and from here you can test to see how your particular engine responds. You will find that if you're running pure water that too much will definitely hurt power but with the usual 50:50 water/methanol mix you don't see a dramatic drop off since the methanol is a fuel.

50:50 by mass which would be 60:40 by volume where 60% of volume is methanol. However sometimes proportion of 50:50 by volume is also used but it has slightly different properties.

Well thank you both for your answers. Inwas thinking sonthat full boost set full duty but another point of view is sometimes really usefull. I am using 50:50 mass at the moment, my question was what happen if I run 2000 cc/min flow of wmi and 300 cc/ min per injector on a 4 cylinder engine ( i took a really excessive exemple I know) , would’that be ok if my lambda is correct or Ill I inject too much water? If so when to know the right amount except’using aem recommandation?

best regards Guillaume

As far as I remember the recommendation from AEM is to set your mixture 1 AFR leaner than your best power AFR and then start adding WMI until you'll reach that AFR again but with WMI this time. That should bring you very close to optimal proportion. If you want to experiment and play with different proportions then I would suggest you going to a dyno or any other means of recording the effects of changing the AFR by using different amounts of WMI. It is very difficult to predict what exactly is "too much" or "not enough" for your particular combination...

I remember Andre in the webinar said that he's not seen any lambda difference with the 250cc nozzle in the GT86 he was using for demonstration (before and after WMI injection)

@georg1970 can you point to the source with 1 AFR leaner?


It was some aem instruction i Googled

It all depends on what your wanting from the water meth, are you wanting it to make power or use it for It's knock safety parameters? This 1 AFR leaner stuff I'm not sold on and never seen it done like that especially if it's someone just repeating what they have read somewhere on google!

Water meth is very popular here in the UK, it's either added around areas of knock or tuned as a whole to make the power but you'll find if you add WM to an already tuned car you'll loose power and it will have to be retuned to suit, AEM have a calculator and I'm sure if you stick them an email or phone them, they will advise you on your injector size based of you requirements, that's what I've done in the past with Aquamist.

I'm sure you are getting information from original manuals in hard copies from manufacturers but to me it is absolutely fine to read their instructions from enternet. In that case it was manual from AEM, not from someone who read it somewhere - I'm old enough to know the difference and i would never advise something that is not comming from manufacturer regardless if you trust it or not.

Oh dear

What? Still not buying it?)) The old RTFM still holds true))

Look mate, I'm not clogging up the lads post anymore because of a immature but hurt grown man can't take a comment that opposes his. I've met many people like you in my career and have absolutely 0 time for you! This is also why I hate giving advice online (people can't seem to stand it when their opinion or "advice" is questioned) you continue to copy and paste and I'll continue to actually do it in practice failure and successes alike. I wont be replying to anymore of your comments so please don't waste anymore of your time on me.

Of course it is all about me being wrong))

PS I absolutely can take any opinion from anyone when it is done in respectful manner. Your post wasn't that. And if you cannot tell the difference between that it is not my fault. What goes around comes around.

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