Catatafish wrote:
Bump, any reason not to use water/meth on an otherwise stock subaru? Car is a legacy twin turbo b4 rsk
It's not going to do much good without a re-tune to take advantage of it, at the very least.
IIRC, per Aquamist best location is about 12"-18" before the throttle body. Liquid should have time to atomize and disperse well enough to not worry about manifold shape, in theory.
And while I don't look to NICO for anything technical anyway, don't expect to get good, reliable results from a fit-together mish-mash of junkyard parts. You need a good pump, you want a PWM (pulse-width modulated) valve -- basically an injector, you need a failsafe of some sort, and a way to tune the water/meth delivery.
Catatafish wrote:
Bump, any reason not to use water/meth on an otherwise stock subaru? Car is a legacy twin turbo b4 rsk
There is no reason to not do it. It can only help... unless you "do it wrong". It's very easy to do it "right". Just like any other modification, there's a methodology to implementing it.
jsquared wrote:It's not going to do much good without a re-tune to take advantage of it, at the very least.
Correct, and that "re-tune" can simply be turning up the boost by whatever means convenient.
jsquared wrote:Liquid should have time to atomize and disperse well enough to not worry about manifold shape, in theory.
That's exactly right. The farther away one puts the nozzle, the longer distance the mist must travel before it reaches the final destination. More distance = more time = more evaporation = more air cooling. The closer it's placed, the reverse happens and more of it enters the combustion chambers. There it flash evaporates and provides an anti-detonant effect.
jsquared wrote:And while I don't look to NICO for anything technical anyway, don't expect to get good, reliable results from a fit-together mish-mash of junkyard parts. You need a good pump...
-best advice in this thread so far!
jsquared wrote: you want a PWM (pulse-width modulated) valve
Nah, with today's PWM pumps, pressure can be modulated so as to match spray volume proportionately to engine load. With water injection, the PWM valve/injector-type setup is very beneficial. The margin of error with pure water is very narrow. Spray a drop too much and you misfire. Inject a drop too little and you're leaving power on the table or running on the ragged edge. Whereas with water/methanol injection, you've got lots more latitude. The share of methanol radically accelerates the water's evaporation rate for more total cooling than water can achieve by itself. (In a water/meth setup, the alcohol serves as an accelerant while the water does the heavy lifting with octane and cooling.) Keep in mind, too, that Catatafish's Subaru has a very short intake tract. Thus, fast air cooling is even more important than with conventional engines.
jsquared wrote: you *need* a failsafe of some sort
Nope, it's not strictly necessary (but is always a great enhancement). One can benefit handsomely without any tune change at all (because cooling and octane are stress relievers). Only if one aggressively cranks up the boost, advances timing, leans out the mixture, or runs lower octane (or does all at the same time which is wicked fun) does one walk with the Grim Reaper.
jsquared wrote: and a way to tune the water/meth delivery.
Now, you're back on the path of righteousness and truth. There are a few very good and some excellent options out there nowadays. 
OK, you can modify the "need" a failsafe to highly highly highly enthusiastically recommended 
I've been contemplating adding a meth injection system on my truck (no super or turbo charger) - from the aspect of using it when towing but not using it for daily use. The GM MAF system is more expense than a turbo or SC setup:
http://www.snowperformance.net/stage-2-gm-maf-boost-cooler.html
Need Nitro and Meth? http://www.snowperformance.net/nitro-booster.html
I wanted to run meth on my M90 gen5 boosted 3.8liter. However several people said that it would strip the Teflon coating off of the rotors making the super charger a big paperweight.
So, not even once, did I do it.
Nick_Comstock wrote:
I wanted to run meth on my M90 gen5 boosted 3.8liter. However several people said that it would strip the Teflon coating off of the rotors making the super charger a big paperweight.
It can happen. When it does, the water itself provides ample sealant between the lobes. So, full functionality is maintained and gains are significant. However, then your charger is effectively hooked on that meth stuff that Mr. Mackey warned us about. With that said, you can always inject after the throttle for zero problems. You'll get little intercooling effect, but the octane boost is still a great thing.
In the OP's case, i'm after it for the detonation-resistance properties. I have a massive intercooler on the car already.
The problem is that i'm too lazy to put a real standalone ECU on the car, so i'm running a stock ECU. The stock ECU has a chip in it to remove boost cut and use bigger injectors, and also has a rather large timing jump over stock at WOT. On top of that, i run an old HKS PFC FCON setup that also alters timing from there and lets me control even larger injectors.
Basically, i'm piggybacking enough crap, adding timing at every step along the way, to "control" 680cc injectors (stock was 330cc) while still using a stock ECU as the base.
Oh, and i have a big cam, a turbo capable of flowing about 3-4x the CFM the stock turbo was, at about 3-4x the stock turbo's oem pressure level.
Basically, it's all a recipe for epic disaster. I got a cheap meth kit, so maybe it'll let the car live for awhile longer without having to deal with actually tuning something, because that's annoying and takes effort. 
Swank Force One wrote:
The stock ECU has a chip in it to remove boost cut and use bigger injectors, and also has a rather large timing jump over stock at WOT. On top of that, i run an old HKS PFC FCON setup...(stock was 330cc) while still using a stock ECU as the base...
Yep... Somebody's obviously building a 323 GTX. :D I've had 3 of them and water/meth is the answer to everything (except the peanut brittle/porcelain alloy transmission)!
