Water Injection [Archive]

chucktoo

02-05-2005, 09:33 PM

I my experiance the ERL Aqua-Mist 2D systems rocks. It will meter water mix in direct proportion to fuel. I am currently running 18% water mix to fuel by volume.

The 2D has high speed valves that are controlled by the signal that goes to the fuel injectors. I run dual 2D systems one off of cylinder 1 and the other off of cylinder 2- this is because the firing order is 1-3-2-4 . I have very uniform water delivery.

Here are two very good resources.

http://www.aquamist.co.uk/

http://www.aquamist.co.uk/phpBB2/

How much water you use depends on what boost pressure you turn the water injection on at and how hard you drive.

My water injection turns on at 12 psi of boost so in normal sane driving it is seldom used and water consumpton is minimal.

Since I live in NE and it gets cold my water mix is 1/3 methanol and 2/3 distilled water - which freezes at ~-20F.
There are a bunch of place that will deliver 5 gal pails of methanol to your door - not a problem to get it.

http://www.ashchem.com/adc/chemicals/faq_answer.asp?typeID=3&is_header=N

If you were extemely conservative you would plan on water injecton being on all the time for one tank of gas so it would be ~20% of the size of the gas tank - this is gross overkill. I have a 3.7 gal water tank and a 16.9 gal fuel tank or 21% and I don't even dent the water tank after an evening of dyno runs. Maybe is you were track racing and on boost all the time but I doubt you could use more that 10% water to fuel.

In a 2D system you size the water injection jets based on your fuel injector size . I have 4 PE-850 fuel injectors so that make max 3,400 cc/min so the WI for 20% would be 3400x.2 = 680 cc/min . I currently have 2 1.0 mm jets that flow 310cc/min at 140psi each for a total of 620cc/min so I am running 18% water to fuel . It runs great -you do have to tune for it - lean the mixture out and add advance and boost.

The guys at PDX are very good at WI tuning - Jeff's please add your tuning advice.

I am adding 4 more 0.3 mm jets directly into my manifold risers that have been tumbler deleted for another 4x170cc or 680cc/min making my total 990 cc/min or 29% W/F. This sounds like a lot but they ran 40% in WWII fighters. By reducing my water pressure I can change the ratio if it is too much. I am trying to replace a FMIC and race gas with a large TMIC and lots and lots of water. It will be an intersting experiment.

I think I am at the fringe of Water Injection - the only crazier ones are the guys that inject water before the compressor inlet to make the compressor look larger by making the air more dense. You know how much better you turbo runs on cold damp days ? This makes every day a cold damp day - not clear if it chews up compressor though.

One guy is actually adding nitromethane to his water but this is totally craziness in my book.

I hope the Jeff's comment on slight less extreme systems like a 1S and their results.

There is another long discussion on how you make the system fool proof so you don't blow up motors when the water fails.