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Lets Talk Water Meth Injection


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I want to see what mine will do or feel like. I was a little worried that having my pump and tank in the trunk was to far. So i installed a solenoid valve close to the jet by the intake. Feel ill only use it over 22 psi progressively. Ill be using a bit of NOS as well.

This was a nice read up.

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I found those nylon hoses don't like engine bay heat.

Worth the extra $$ to go braided stainless at initial purchase.

It seems a common theme, tuners are reluctant to make full use of W/M, rather prefer to do their usual tune then let you add W/M to eliminate knock.

I guess it's almost like starting again and would push the tuning price way up.

From what I've seen it's mainly enthusiasts making the most use of water injection.

Mr MJTru, I know zero about NOS but I'd be adding brew way, way earlier than 22psi.

My thinking is to eliminate knock before it gets a hold.

By the by, here's a great read about water injection in WW2 aero engines.

Hats off to this guy, no electronic knock ears in those days.

http://www.enginehistory.org/Frank%20WalkerWeb1.pdf

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The allies were using what they had handy to eliminate knock, but carrying all that water lowered the aircraft payload, and it only offered 10 minutes of 'wartime emergency power'.

The Germans were making synthetic fuels which resisted knock, similar to you just running e85, which is the better option.

Unless you could automate a low water/meth level boost drop into the map, and guarantee the system won't surge around corners when low, I doubt any tuner will rely on it for knock protection. (unless you signed a disclaimer or similar.)

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Sound like he is scared to tune to it.

If you just put it on you will drop a few hp since combustion is slowed. If your running it just in case you get a bad batch of fuel it might be tuned to the raggered edge.

To use it to clean your engine, upper engine cleaner is more convenient.

thats what I feel too, just suck i already fitted that expensive aquamist kit lol..

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You really need to push it to see real gains with wmi. If you only put a few degrees in it you might see a few hp. Its when you up the boost and lean on it is where it shines.

Down side is one blocked jet and your stressing everything. For this reason im now leaning towards larger single jet and as always good filters.

Also someone mentions a 22 psi trigger point which is fine, so long as you start leaning onion it after your switch point. Even with solenoids on the jet you always run the chance of a small air bubble from cruising vacuum, decel etc.

Also, meth is good but can corrorde jets etc like someone mentioned. Im trialing some light machine oil mixed with the meth, then mixing water and a few drops of dawn for mix ability to extend nozzle cleaning intervals. I also want to try r30 oil which is a good mineral oil used in rotas and 2smokes. i had to switch mine off and run a straght pump tune since the mrs is using it atm. I wss running 50!50 by weight. Another thing i want to try is less meth until i need to back something off in the tune.

As always lots of playing around.. best to learn to tune yourself before hand

Shameless plug i still have a brand new aquamist 1s system for sale. See sig

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Full boost at 18psi, but I start at 50% injector cycle and/or 10psi and its on 100% injection at 80/18 [from memory, but I can check tonight]. 22 is way too high for effective use as a starting point IMO, you want the cooling effects to begin way before [for knock] that then as your revs rise the extra power also comes on.

But I'm not racing, only open road.

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Intresting. I cant speak for no one else. But for me and our fuel type and tune leaving out the actual mechanics of the build motor. I start at 22 psi. My max boost is 30 psi on rb26. Its weird for me to hear all these opions of what or when to start using it. I hate the stuff realy. I rather drop the fuel (quality ) and just use NOS. but im new at using METH. ill see how it goes. Starting at 22 psi works for me.

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Full boost at 18psi, but I start at 50% injector cycle and/or 10psi and its on 100% injection at 80/18 [from memory, but I can check tonight]. 22 is way too high for effective use as a starting point IMO, you want the cooling effects to begin way before [for knock] that then as your revs rise the extra power also comes on.

But I'm not racing, only open road.

I ran 10 psi with no hot egt's at all much less knock. imo 22psi for me is were i start cooling things down and controlling things.

A tuner that have a limit of lets say 15psi would have a way more aggressive igniton setup that say a person thats running a higher booster setup. So maybe your getting higher egts at lower boost than i am. Im not sure unless i see an actual log. But as of now i can only guess

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I've used WMI for a long time.

You really want the water and meth coming on before the engine starts to ramp up to peak torque. I think 22psi is way too late for that. I would be starting it at 10psi.

(I ran 20psi of boost and had my variable controller starting at 5psi and finishing (full pressure) at 21psi)

Peak torque and building up to peak torque is when it's going to knock. It's also where the response is, and extra timing there will make it come onto boost sooner.

I'm considering a WMI kit and using my link G4+ with a 3d table to control it. Would be perfect.

Just another note - next time I make a kit I'm going to create some sort of purge switch in the cabin so that at least once or twice I will run the kit for a few seconds on idle or cruise to push out the air pockets.

Had the kit running full pressure on idle, didn't run bad or anything. Good to clean the engine too. Really good! Clean engines always run better :)

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  • 2 weeks later...
  • 1 year later...

TBH I got a dyno tune with basic WMI settings then I went away and played with it. I was looking at lowering knock and seat of pants increasing power [no wide band or anything flash]. I then settled on settings and went back and got the car tuned again. The shop I went to knew what it was and what it did but didn't really know the best settings or how to improve it on the dyno.......just too much going on for them I guess.

So atm its 8psi and 45% and full WMI by 14 and 75% and I've been running it for 6 years now.

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TBH I got a dyno tune with basic WMI settings then I went away and played with it. I was looking at lowering knock and seat of pants increasing power [no wide band or anything flash]. I then settled on settings and went back and got the car tuned again. The shop I went to knew what it was and what it did but didn't really know the best settings or how to improve it on the dyno.......just too much going on for them I guess.

So atm its 8psi and 45% and full WMI by 14 and 75% and I've been running it for 6 years now.

what size jet?

im using 550cc or thereabouits, 60% at 1psi and all in at 10psi. doesnt flood it at low boost even if i use water only

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Wow thats early - 1psi - using it when its not really needed IMO. I will have to look at my jet, the kit came with two but from memory I think I'm using the lower one which could have been 375???? But will confirm and get back to you on it.

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I think 1psi is too early, you will activate the kit too often and waste water for when you need it.

I would start the kit at 5-6psi. Beyond that is when the torque starts to come on hard.

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I do about 3000km a year so I'm happy to burn through it.

I find I virtually never hit positive boost unless I'm overtaking or just giving it a squirt so the time difference between starting early or late is minimal.

But when holding it 1psi I was initially suprised it didn't put the flame out

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The other downside is you could end up with unburnt WMI in the combustion chamber when you park it..............

If you set it higher - like 6psi - as you cruise home/up your street you will not use any WMI and your chamber will be dry when you park it. And I'd be totally surprised if you see any difference in performance at all from the higher setting.

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