# water meth injection on stg 2 vf blower



## pjung23551 (Jun 18, 2008)

Hey guys, a question for you. So this week, I sat in a buddies car who had a water/meth injection "snowdevil" or something for his vf stg 2, and the car absolutely scoots. I feel he's running at least 40-50 hp additional, and the car's pickup absolutely rocks. 
I had a few questions however. Will my ECU be able to adapt to a stop in flow with the water/meth setup if ever a sitaution occurs when the reservior tank goes dry? I understand they have a sensor and all when the water/meth is low, but still, I find this







. I'm not sure if I should be wary about a system that cant run on both standard pump gas vs gas+watermeth. 
What is the difference between water/meth and nitrous? Nitrous upon increased temperatures, (combustion) splits into nitrogen and oxygen. This increases charge density, = more air in = more power. But where does water/meth differ in all of this? So the water is used to rapidly absorb heat upon evaporation and methanol cools and increases octane? 
Finally, would running a water meth setup increase wear and tear on the sparkplugs, cat, and emissions systems in this car?
Are there systems that can resort back to a stock mapping if water/meth solution runs low?


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## [email protected] (Jan 13, 2005)

*Re: water meth injection on stg 2 vf blower (pjung23551)*


_Quote, originally posted by *pjung23551* »_Will my ECU be able to adapt to a stop in flow with the water/meth setup if ever a sitaution occurs when the reservior tank goes dry?



Your engine is equipped with a knock sensor that will pick up the noise that comes from uncontrolled combustion. This is the last line of defense, but it does work and reacts quickly enough to at least partially protect against a malfunctioning water/meth system or one that you've allowed to run dry. To guard more actively against such an occurence, however, you can invest in some extra bits.

_Quote »_I'm not sure if I should be wary about a system that cant run on both standard pump gas vs gas+watermeth.

I'd say that 99% of VW kids that I cater to install a base system and don't buy the safeguard extras. However, probably 60% of my Audi guys (read "adults with responsiblities") do elect for the extras. Water/meth's tuning reputation was mostly created amongh the VW ranks. This should clearly reveal that concern is out there but the danger just isn't that great. The likelihood of big trouble is minimal but still worth considering.

_Quote »_What is the difference between water/meth and nitrous?

There's almost nothing similar about them aside from spraying into the intake and the cooling benefits. However, water/meth is a perfect complement to the happy gas. It's the beast tamer that nitrous so badly needs much of the time.

_Quote »_Nitrous upon increased temperatures, (combustion) splits into nitrogen and oxygen. This increases charge density, = more air in = more power.

Right, N2O splits into nitrogen and oxygen when heated in the combustion chamber. The extra supplied oxygen combines with the extra fuel that's injected at the same time and thusly creates more cylinder pressure. The nitrogen acts as a buffer to keep the mix from detonating violently. (Furthermore, pure oxygen injection would not only burn any extra fuel but also the aluminum cylinder head and anything else in its presence.) As the frozen liquid evaporates into gas it reduces the intake air temperature which helps keep things happy and calm.

_Quote »_But where does water/meth differ in all of this? So the water is used to rapidly absorb heat upon evaporation and methanol cools and increases octane?

Water/methanol cools the intake air temperatures and also boosts octane in a big way. The *water* does the majority of both cooling and octane boost. The methanol cools much faster, however. This helps with distribution consistency between cylinders and widens the safe tuning envelope compared to spraying water alone.

_Quote »_Finally, would running a water meth setup increase wear and tear on the sparkplugs, cat, and emissions systems in this car?

No, it will reduce wear and tear on all those items. Long term reliability will increase -not the reverse.

_Quote »_Are there systems that can resort back to a stock mapping if water/meth solution runs low? 

These kits don't adjust your ECU mapping at all. You set up your main ECU to your liking and then the water/meth kit will make the tune safe. In this sense it is just like running race fuel. The safeguard system that I mentioned before will not change your ECU mapping, either. What it will do, however, is purge your boost immediately in case of a malfunction or a run dry situation. You might throw a code, but you won't throw a rod.


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